HVAC Installation Procedures Manual

HVAC Installation Procedures Manual
HVAC
Installation Procedures
Main Menu
WELCOME
HVAC
Installation
Procedures
Using The
Electronic
Manual
This CD-ROM contains an expanded version of the HVAC Installation
Procedures Manual. The following information is included in addition to the
material provided in the paper edition:
• A printable quiz for each section of the book
• Printable exercises that test and reinforce knowledge of the procedures
contained in the book
• A list of tools referenced in the manual
Click on a folder at left to view that part of the
HVAC Installation Procedures CD-ROM.
Important Notes
Quizzes
and
Exercises
1. Take the time to review the section on Using the Electronic Manual. This
section contains an overview of the buttons, controls, and features of this
particular electronic document. If you don't become familiar with the
navigation tools, you will have difficulty in finding your way around.
2. When you click on a Help button/menu choice, you will see the Acrobat
Reader Help information, which has information on using all of the features
and navigation tools available in the Reader.
3. When you select an option other than HVAC Installation Procedures at
the Main Menu, you open a Microsoft Windows folder. To return to the Main
Menu and select another folder, you must close the open folder using the
Close command in the File menu.
Microsoft is a registered trademark, and Windows and Windows 95 are trademarks of Microsoft Corporation. Adobe and Acrobat are
trademarks of Adobe Systems Incorporated. All other brand or product names are trademarks of their respective holders.
HVAC Installation
Procedures Contents
SECTION
1
SECTION
2
SECTION
3
SECTION
4
SECTION
5
SECTION
6
SECTION
7
SECTION
8
SECTION
9
SECTION
10
The Organized Installation
Safety
Installing Fasteners and Anchors
Rigging, Hoisting, and Moving
Piping Systems
Forced-Air Duct Systems
Field Wiring
Gas Furnace Installation
Split System Installation
Packaged Unit Installation
Appendix
Glossary
Index
Tools List
THE ORGANIZED INSTALLATION 1
▼ THE ORGANIZED INSTALLATIONN
SECTION 1
INTRODUCTION
This section provides the basic information needed to plan and prepare for the installation of
residential and light commercial air conditioning and heating systems. Planning the installation
and an overview of the tasks and sequence for a typical installation are covered first, followed by
a brief description of the tools used to perform common installation tasks. Also given in this
section are guidelines for acquiring and maintaining good customer relations before, during, and
after the installation.
INSTALLATION MENU
Planning the Installation
Typical Installation Tasks and Sequence
Installation and Start-Up Checklist
Installation Tools and Equipment
Hand Tool Set
Measuring and Layout Tools
Portable Electric and Cordless Tools
Ladders
Customer Relations for Installers
THE ORGANIZED INSTALLATION 1
Table of Contents
Map
References
Section Topics
PLANNING THE
INSTALLATION
Reliable system installations do not happen by
accident; they require careful planning
(Figure 1-1). Local ordinances governing equipment placement, electrical hookup, materials,
and the protection of the environment must be
obeyed. This is necessary to avoid any inconvenience, increased cost, and bad reputation
resulting from a failed inspection. Construction
permits must be secured in some localities. The
specific site for indoor and outdoor equipment,
as well as any ductwork and piping, must be
identified and prepared to receive the equipment.
The proper type of equipment for the job must
be selected and ordered. Ducting, piping, and
electrical materials must be selected and purchased by a qualified engineer or salesperson
based on a survey of the job. For new construction, this survey may be done by consulting the
builder and looking at the blueprints and specifications for the job.
For a replacement job, the survey is completed by visiting the job site and consulting with
the customer to determine their needs. Heating and cooling load estimates for the building
are made and the existing air distribution system, utilities, and electrical service are
evaluated to determine their adequacy to support the new equipment.
▼ Figure 1-1.
Planning
•
•
•
•
•
•
•
EQUIPMENT
MATERIALS
PERMITS AND CODES
SELECT EQUIPMENT LOCATION(S)
PREPARE EQUIPMENT SITE(S)
SCHEDULE JOB/COORDINATE WITH OTHER TRADES
INSTALL/START UP/CHECK OUT
TYPICAL INSTALLATION
TASKS AND SEQUENCE
The installation of any system or component
should always be performed as recommended
by the manufacturer’s specific installation instructions. This is because the actual tasks and
their sequence can vary widely based on the
size and type of system being installed. A typical approach is to start by preparing the
location and setting the equipment in place
(Figure 1-2). Electrical wiring is run to the
equipment location or to a disconnect which
feeds the equipment. Local codes may require
that this be done by a licensed electrician.
Ductwork and combustion vents are connected
to the equipment as needed. This is followed
by the installation and connection of the refrigerant, gas, and condensate piping to the
equipment, as required. The final electrical
hookup is made to the thermostat and to the
unit’s control circuits.
▼ Figure 1-2.
Installation Sequence
•
•
•
•
•
EQUIPMENT PLACEMENT
RUN WIRING (ROUGH IN)
RUN DUCTING WITH FINAL CONNECTION
RUN PIPING WITH FINAL CONNECTION
ELECTRICAL HOOKUP
THE ORGANIZED INSTALLATION 1
Table of Contents
Map
References
Section Topics
Following completion of the initial installation
tasks, the system must be readied for service
(Figure 1-3). This often requires that the refrigerant and gas lines be leak-tested and, if
necessary, repaired. If installing a field-piped
cooling system, the system must be evacuated
and the refrigerant charge checked. During this
step, it is essential to follow all installation instructions and guidelines provided by the
manufacturer. Next, the equipment start-up procedure is performed to check the operation of
the equipment, make adjustments, and check
out the operation of all safety controls.
The final step is a thorough cleanup of the
equipment and the work area. You should also
give the customer the owner’s manual(s) along
with simple, courteous instructions on how to
operate and maintain the system.
INSTALLATION AND STARTUP CHECKLISTS
Most manufacturers provide installation and
start-up checklists (Figure 1-4) in the literature
supplied with their equipment. At appropriate
points throughout the installation, these checklists should be used to confirm the completion
of various installation tasks. During system
checkout, the lists are used to record the unit’s
performance characteristics.
INSTALLATION TOOLS AND
EQUIPMENT
▼ Figure 1-3.
Commissioning
BEEP
BEEP
LEAK
DETECTOR
SOLUTION
1. LEAK TEST AND REPAIR IF NEEDED
2. EVACUATE AND DEHYDRATE
3. CHARGE SYSTEM (REFRIGERANT AND ANY EXTRA OIL)
4. INSULATE REFRIGERANT LINES
5. FINAL INSPECTION
6. START UP AND CHECK OUT
7. CLEAN UP
8. CUSTOMER INFORMATION/INSTRUCTION
▼ Figure 1-4.
Confirm Correct Installation Using Installation and
Start-Up Checklists
K
EC
CH IST
L
A quality installation depends on using the right
tools and equipment for the job. General-purpose tools and equipment are described here.
Specialized tools and equipment are described,
where relevant, later in this book.
Hand Tool Set
You should have a tool box equipped with a
variety of quality hand tools (Figure 1-5). Specialized tools needed to service refrigeration
systems such as service valve adapters, etc.
should also be included in this tool set.
Measuring and Layout Tools
Measuring and layout tools used to determine
length, height, diameter, levelness, or plumb
must be easy to use, accurate, and durable.
Common measuring tools include:
• Measuring tapes and folding rules
• Squares
• Levels
• Plumb bobs and chalk lines
▼ Figure 1-5.
Typical Hand Tool Set
THE ORGANIZED INSTALLATION 1
References
Section Topics
5
6
QUICK NOTE
4
Squares – Squares are used for measuring,
marking a line for cutting, checking
squareness, and checking the flatness of materials. Two kinds of squares are commonly
used: a combination square and a framing or
carpenter’s square.
The combination square (Figure 1-7) consists of a blade and a sliding adjustable head.
The blade and head incorporate a 90° square
and a 45° miter square that allow the tool to
be used to check and/or mark out either 90°
or 45° angles. Most combination squares have
a built-in spirit level and a hardened scriber
that can be used for marking metal.
Carpenter’s squares (Figure 1-8) are used
mainly as a straightedge and to mark out rightangle lines. They are also used to check the
inside and outside squareness and flatness
of materials. Both the body and tongue are
stamped with graduations that are divided into
inches, allowing the tool to be used as a ruler.
Framing squares usually have tables and formulas marked on them to make calculations
for area and volume.
▼ Figure 1-6.
Folding Rule and Measuring Tape
3
Measuring Tapes and Folding Rules – Measuring tapes and folding rules (Figure 1-6) are
used for making most measurements. They
are normally marked with both English and
metric scales.
Folding rules come in 6- to 10-foot lengths,
with hinges for folding. Some are equipped
with a graduated sliding brass extension that
is useful for making depth and inside measurements. Because of its stiffness, a folding rule
is useful for making overhead and vertical
measurements.
Self-rewinding measuring tapes are made
of steel or fiberglass and usually come in 10to 30-foot lengths. A hook on the end of the
rule grabs onto the work piece, making it easier
to use when making long measurements. A
lock holds the tape in the open position and a
rewind mechanism retracts the tape when not
in use. Longer tapes are available for measuring longer lengths.
2
Map
1
Table of Contents
• Folding rules require little maintenance, except for periodic lubrication
of the joints.
• Avoid dropping a folding rule as the
fall may loosen the joints enough to
cause inaccuracies.
• To work properly, steel tapes must
be kept clean, dry, and free of kinks.
• Keep water and mud out of the steel
tape case as they can cause rust
and other damage to the rewind
mechanism.
▼ Figure 1-7.
Combination Square
BLADE
HEAD
▼ Figure 1-8.
Carpenter's Square
TONGUE
BODY
THE ORGANIZED INSTALLATION 1
Table of Contents
Map
References
Section Topics
Levels – Levels are used to determine the horizontal (level) or vertical (plumb) alignment of
structural members, piping, or mounted components. Levels are made in simple and
electronic models and come in various lengths.
A general-purpose spirit level (Figure 1-9) is
normally adequate for use in HVAC installation
work.
Common spirit levels have three vials. The
two end vials are used to measure vertical
plumb while the center vial is used to measure
horizontal level. The item being checked is level
or plumb when the air bubble within the appropriate vial is centered between the lines etched
on the vial.
When not in use, levels should be stored in
a manner that ensures they will not be twisted,
bent out of shape, or have their vials broken.
Plumb Bobs and Chalk Lines – Plumb bobs
(Figure 1-10) are balanced weights used to find
plumb over long vertical distances. When suspended from a height by a string attached to its
exact top center, and allowed to hang freely,
the force of gravity causes the plumb bob string
to settle in the plumb position.
A chalk line (Figure 1-11) is used to mark a
layout line between two points on long flat surfaces. It typically consists of a case filled with
chalk and a length of line on a retractable reel.
Each time the chalk line is pulled out of the box,
it is automatically chalked. To use a chalk line,
the line is pulled from the case, stretched taut
between the two reference points to be connected, then snapped. This causes the chalk
on the line to mark the surface underneath the
string. The chalk line must always be kept in a
dry place, or moisture may cause it to become
clogged.
▼ Figure 1-9.
Spirit Level Used to Check Plumb and Level
PLUMB VIAL
LEVEL VIAL
▼ Figure 1-10.
Finding True Vertical Plumb with a Plumb Bob
STRING
PLUMB BOB
▼ Figure 1-11.
Mechanical Chalk Line
LINE
HOOK
Portable Electric and
Cordless Tools
A variety of electric and/or cordless hand drills,
saws, etc. are used regularly on installations.
Electric tools normally operate on 110-120 volts
AC, and are plugged into an outlet near the work
location.
Cordless drills (Figure 1-12) and other
cordless tools are useful for working where electrical outlets are not available. Cordless tools
have a detachable and rechargeable battery
pack that runs the motor. Generally, the higher
the voltage rating of the battery pack, the higher
the torque or capacity of the tool. Most quality
tools have chargers that can quickly recharge
the battery pack. However, an extra battery
pack should be purchased so that the job is
never halted while waiting for a battery to recharge.
CASE
HANDLE
▼ Figure 1-12.
Cordless Driver-Drill and Charger
Po
50 wer-D
00
rill
er
00
Ch
ar
r
ge
50
THE ORGANIZED INSTALLATION 1
Table of Contents
Map
References
Section Topics
Electric and Cordless Drills – The specific
drill used depends on the diameter, depth of
the hole, and type of material to be drilled
(Figure 1-13). Drills are rated according to the
maximum horsepower (hp) developed by the
motor. Generally, the higher the hp, the more
power or torque is available to the drill.
Drills are also rated by the largest drill bit
(Figure 1-14) shank that the chuck will hold.
Chuck size is a good indication of the largest
size hole the drill can easily bore through hard
metal. Drills can be fitted with 1/4-inch, 3/8-inch,
or 1/2-inch chucks.
Drills with variable-speed and rotation-reversing features are desirable for installation work.
Reversing the rotation of the drill makes it easier
to release stuck and jammed bits and to remove screws, etc. Variable speed allows holes
to be drilled at different speeds. Generally, the
harder the material being drilled, the slower the
drilling speed. Drilling iron or steel is best done
at speeds in the range of 300 to 500 rotations
per minute (rpm), while drilling in softer materials such as wood is better done at higher
speeds up to about 1,200 rpm. The use of very
slow speeds also makes it easier to start holes,
run in screws, and perform other similar operations.
A hammer drill (Figure 1-15), so named because of its hammering action, is commonly
used to drill holes into masonry. It rotates and
hammers at the same time and drills much
faster than regular drills. Hammer drills have a
depth gauge that can be set to control the depth
of the hole being drilled.
Circular, Reciprocating, and Jig Saws – Installing HVAC equipment requires that holes be
cut for pipes, ductwork, vents, etc. Wood and
other materials must also be cut to build support structures for equipment and/or to mount
electrical and other panels. These cutting jobs
are normally done using circular, reciprocating,
and/or jig saws.
QUICK NOTE
Before drilling, make sure work is
firmly supported and clamped. Make a
starter hole with an appropriate punch
to prevent the bit from wandering.
▼ Figure 1-13.
Electric Drill Used to Drill Hole in Metal I-Beam
▼ Figure 1-14.
Types of Drill Bits
TWIST
DRILLS
COUNTERSINK
HOLE SAW
WOOD PLUG CUTTER
BIT EXTENSION
POWER
WOOD
BIT
BRAD-PT.
WOOD
BIT
WOOD
SCREW
PILOT BIT
MASONRY
BIT
▼ Figure 1-15.
Hammer Drill Used to Drill Holes in Masonry
THE ORGANIZED INSTALLATION 1
Table of Contents
Map
References
Section Topics
QUICK NOTE
• A circular saw with a large diameter blade is of little value if the saw motor lacks the horsepower
to drive it.
• If adequately powered, a saw with no-load blade speeds ranging between 4,000 and 5,800 rpm
makes a faster, smoother cut than one that runs at a lower speed.
• Too much cutting blade depth increases the chance of saw kickback and can cause the cut to be
rough. For standard steel blades, allow one whole tooth to project below the material to be cut.
For carbide-tipped blades, allow 1/2 a tooth.
Circular saws (Figure 1-16) are used to make
straight cuts in various materials. The size of a
circular saw is determined by the diameter of
the largest blade that can be used with the saw,
which determines how thick a material can be
cut. Saws using blades of 7-1/4 and 8-1/4
inches are the most popular. Circular saws have
upper and lower guards that surround the blade.
The upper guard is fixed; the lower guard is
spring-loaded and retracts as the saw cuts into
the work piece. The saw baseplate rests on the
material being cut and can be adjusted to
change the depth of the cut or to make bevel
cuts ranging between 0° and 45°.
There are a wide variety of blades available,
each designed to make an optimum cut in a
different type and/or density of material. Generally, blades are standard steel or
carbide-tipped. Carbide-tipped blades stay
sharper longer, but they are more brittle and
can be damaged if improperly handled. The
number of teeth on a blade, the grind of each
tooth, and the space between the teeth (gullet
depth) determines the smoothness and speed
of the cut. To select the right blade, use a blade
recommended by the blade manufacturer for
the type of material being cut. Make sure that
the blade diameter, arbor hole size, and maximum rotation speed fit your saw.
Reciprocating saws (Figure 1-17) are heavyduty saws with a back-and-forth blade motion.
They can be used for cutting through floors and
partitions including nails, wire mesh backed
plaster, studs, and beams. Variable-speed models with speeds ranging from 0 to 2,400 strokes
per minute (spm) are best. Higher horsepower
and slower speeds are generally needed when
cutting through metals or when cutting along a
curved or angled line. The typical length of the
horizontal sawing stroke is 1-1/8 inch. A good
saw will have the capability of mounting the saw
blade so cuts can be made upward as well as
to the left and right.
A jig or saber saw (Figure 1-18) is a lighterduty saw than the reciprocating saw and is used
to make straight or curved cuts. With the proper
blade, it can cut wood, metal, plastic, and other
materials. Variable-speed models with speeds
ranging from 0 to 3,200 spm are best. The typical length of the vertical sawing stroke is one
inch. Other features of a good saw include adjustable orbital action to clear away chips, a
baseplate that can be tilted for bevel cuts, and
a scrolling capability that makes it easier to cut
along pattern lines.
▼ Figure 1-16.
Circular Saw
STEEL
MASONRY
CARBIDE-TIPPED
ABRASIVE
▼ Figure 1-17.
Reciprocating Saw Cutting through a Floor
▼ Figure 1-18.
Jig (Saber) Saw
THE ORGANIZED INSTALLATION 1
Table of Contents
Map
References
Section Topics
A wide variety of interchangeable blades are
made for use with reciprocating and jig/saber
saws. Each type of reciprocating or jig/saber
saw blade is designed to make an optimum cut
in a different kind of material. Always use the
blade recommended by the blade manufacturer
for the type of material being cut.
Portable Band Saw – The portable band saw
(Figure 1-19) is useful for cutting heavy metals. Typical cutting capacities are up to 3-1/2
inches for round materials and 3-1/2 x 4-1/2
inches for rectangular materials. The band saw
has a continuous one-piece blade that runs in
one direction around guides located at either
end of the saw. Two-speed and variable-speed
models are both common. Band saw blades
are made with standard pitch or variable pitch
teeth. Blade materials and the number and pitch
of the teeth are designed to make an optimum
cut in different kinds of materials. Always use
the blade recommended by the blade manufacturer for the type of material being cut.
Extension Cords – An extension cord is frequently used to connect power to power tools.
It should have a suitable wire size for the overall cord length and the proper amperage rating
for the tools with which it will be used
(Table 1-1). This is necessary to prevent excessive voltage drop, power loss, and possible
motor damage. When tools are used outdoors,
only extension cords labeled for outdoor use
should be used. For protection against potential shock from an electrically-shorted power
tool, a ground fault circuit interrupter (GFCI)protected extension cord should be used.
Ladders
Extension and step ladders (Figure 1-20) are
often needed to reach high places, such as rooftops. They can be made of fiberglass,
aluminum, or wood. Fiberglass and wooden
ladders are nonconductive, allowing them to be
used when working around electricity. Aluminum ladders are lightweight and easy to move,
but should not be used where contact with electricity is possible.
Ladders are rated by their total load capacity, which includes the combined weight of the
user, tools, and any materials bearing down on
the ladder rungs. Minimum load capacities used
for installation work are 225 pounds (medium
duty), 250 pounds (heavy duty), and 300
pounds (extra heavy duty).
▼ Figure 1-19.
Portable Band Saw
▼ Table 1-1.
Finding the Correct Extension Cord for the Job
Tool Ampere Rating
Cord
Length
(Feet)
3.5
to
5
5.1
to
7
7.1
to
12
12.1
to
16
Extension Cord Recommended
Wire Size (AWG)
25
18
18
16
14
50
18
16
14
12
75
16
14
12
10
100
14
12
10
–
▼ Figure 1-20.
Extension and Step Ladders
EXTENSION
LADDER
STEP LADDER
INSTRUMENTS AND DEVICES 1
Table of Contents
Map
References
Section Topics
Common extension ladders range in size
from 16 to 40 feet (Table 1-2). Extension ladders are equipped with a rope and pulley
system to help raise and lower the upper ladder section. Self-locking rung latches attached
to one of the sections supports and secures
the raised section in place.
Step ladders are self-supporting, non-adjustable ladders made in heights ranging from 4 to
20 feet. WHEN USING A STEP LADDER,
NEVER STAND ON THE TOP TWO STEPS.
Wooden ladders require proper maintenance. Moisture can be a problem, so they
should be stored in a dry place to prevent rot.
Never paint a wooden ladder. The paint can
hide cracks, splinters, and dry rot. Use of
clear varnish or a preservative oil finish will protect the wood without hiding these defects. For
additional information about ladders and
ladder safety, refer to Section 2.
▼ Table 1-2.
Finding the Correct Extension Ladder for the Job
➧ WARNING
➧ CAUTION
Ladder Size
(Feet)
Maximum
Extended
Length
(Feet)
Maximum
Working
Height
(Feet)
16
13
9
20
17
13
24
21
17
28
25
21
32
29
25
36
32
28
40
35
31
CUSTOMER RELATIONS FOR
INSTALLERS
Appearances Count – When people meet you
for the first time, they form their critical first impression of you based to a large extent on how
you look. Industry studies have consistently
identified the appearance of installers as a factor that many customers consider important
(Figure 1-21).
Ask yourself these questions:
• Do you get enough sleep and look alert?
• Do you practice good personal hygiene?
• Do you wear a neat, clean uniform and clean
shoes?
• Do you promptly identify yourself and show
an appropriate ID?
• Do you smile, display confidence, and polite
respect for the customer?
If your answer to each question is “Yes,” congratulations! You are well on your way to
consistently making the good first impression
your company needs.
If you answered “No” to any of the questions,
you have identified an area for improvement
that can change how people feel about you and
your company. Get to work on making that improvement. You will be glad you did.
Before you head out to a job, look in the mirror and ask: “Would someone’s spouse or
mother want me in the house?”
In addition, your vehicle is a traveling billboard for your company (Figure 1-22). How it
looks and how you drive it can greatly influence
the public’s impression of your company. Make
that positive impression on the road.
• Is your truck clean and in good repair?
• Are your driving habits courteous?
▼ Figure 1-21.
How You Look on the Job is Very Important
▼ Figure 1-22.
Your Vehicle is a Traveling Billboard for Your
Company
ABC CO.
HVAC INSTALLATION
INSTRUMENTS AND DEVICES 1
Table of Contents
Map
References
Section Topics
Treat Your Customers with Respect – In a
way, admitting you into their home is a trusting
gesture of faith by customers (Figure 1-23).
They have faith that you will do no harm, and
that you will treat the premises and occupants
with respect. Do you agree? Think about the
people you invite into your home.
Ask yourself these questions:
• Do you refrain from smoking?
• Do you remember to protect the work area?
• Do you carry rags and carefully clean up after yourself?
• Do you have drop cloths to protect floors and
carpets?
• Do you keep from tracking in dirt?
• Do you return the home to its original condition? (Replace covers, wipe off dirty
fingerprints, clean up drop cloths, etc.)
Good Work Habits Mark You as a Skilled
Professional – As the number of homes with
more than one income has increased, the need
for installers to arrive on time has become more
critical than ever, since in these cases someone may have to take time off from work to wait
for the installer. Be on time. Call if you are going to be late (Figure 1-24). Show the customer
that you have consideration for their time.
It is a good idea to read the product installation instructions before going on the job. Using
a wrong tool not only leaves behind poor results, it tells your customer that you are
unprofessional. Customers notice if you arrive
with a full set of tools, neatly packed. They notice your attitude, and whether it shows a good
work ethic. They can see if you neatly repack
your tools when you finish the installation, too.
It is part of how they judge you and your company. It is also a large contributor to whether
they call your company back for more work.
Review these questions. Any “No” answers
indicate areas that need work.
• Are you on time?
• Do you arrive fully informed and prepared to
do the job?
• Are your tools a full set, neatly packed?
• Do you tackle the installation promptly?
• Do you avoid general social conversation
while working?
▼ Figure 1-23.
Treat Your Customers with Respect...Begin with
Their Homes
▼ Figure 1-24.
Good Work Habits Mark You as a Skilled
Professional
11 12
1
7
5
2
10
3
9
4
8
6
QUICK NOTE
No company wants its employees using
alcohol, drugs, or profanity on the job,
and no customer wants such people in
their home. On the job, always show the
Customer Satisfaction Depends on what
You Say as Well as what You Do – Understanding your customer’s needs is the first step
in achieving customer satisfaction (Figure 1-25).
Imagine that you are the customer. What would
you like to know about a new installation? Your
answer is likely to include items your customer
would also want to know. Helpful Hint: Think
of good communication with your customer as
essential to understanding his/her needs.
When installers do not explain how things
work and fail to give the customer a good over-
customer the kind of positive, professional attitude and behavior you would
expect if YOU were the customer.
▼ Figure 1-25.
Customer Satisfaction Depends on what You Say
as Well as what You Do
THE ORGANIZED INSTALLATION 1
Table of Contents
Map
Section Topics
References
view of how to use and maintain the product,
they leave customers with unanswered questions. Customers appreciate when you explain
how to operate and care for the product/sys▼ Figure 1-26.
tem (Figure 1-26). Be brief, with no unnecessary
Customers Appreciate when You Explain how to
conversation.
Operate and Care for the Product/System
Sometimes, learning your customer’s needs
calls for using your powers of observation. For
example, on a furnace job, a veteran installer
noticed that his customer, a senior citizen, suffered from painful arthritis in her hands. He
realized that the simple task of changing the
filter would be difficult for her. So he suggested
an optional, inexpensive, external filter rack. He
explained how easily the filter slides in and out.
Without hesitation, she purchased the optional
rack. Weeks later, she was telling her friends
about her “helpful furnace man.”
Many customers incorrectly assume that a
brand-new, just-installed product can go for
years without maintenance attention. Suggestion: Explain that today’s high-tech systems,
like today’s cars, need
regular maintenance.
Many top installers show their customers simple, self-help maintenance techniques that prolong equipment life, such as how to change filters. In addition, they make sure the customer can
set the thermostat, as well as explaining items unique to the product. For example, with heat
pumps, the installer might explain how heat pumps work and tell why frost might form on the coil,
and why the outdoor section must be kept clear of snow.
Top installers always leave the product literature packet with the customer because they know
that with today’s high-tech products, these instructions contain information that a servicing technician might need someday. The owner’s manual also contains information that helps the owner
to better understand equipment operation and helps to prevent needless service calls. It is a good
idea to suggest to your customer that they keep the product literature, warranty, etc. in a safe
place.
Dealers who do large amounts of repeat business have trained their installers to make things
easy for the customer. They make it easy to contact the dealer. They check back to make sure the
installation is satisfactory.
Consider these loyalty-building questions:
• Do you leave a business card or put a sticker
▼ Figure 1-27.
with your company’s phone number on the
Always Leave a Business Card or Put a Sticker
equipment (Figure 1-27) or leave a card with
with Your Company’s Phone Number on the
the customer to keep near the phone?
Equipment
• Do you call the customer a day or two later
to ask if your product/system is working properly?
If you answered “Yes,” you are already makg Inc.
ing opportunities for repeat business based on
itionin
d
n
o
Air C
satisfied customers. If you answered “No,” perABC
SA
Air, U 8
n
a
le
4
C
haps you should consider trying one or all of
9
2
555
(522)
these proven business-building techniques.
Finally, remember that your customers appreciate a positive attitude. For example, it is
always best to be professional and avoid “bad
mouthing” older or competitive products. Likewise, if for example, you are late—but it is not
your fault—focus on the positive, getting the
job done, rather than blaming someone else.
Say something like: “I understand how you feel.
I’m sorry. Please know that I will do my best to
have your new furnace installed as quickly as I
can.”
SAFETY
2
▼ SAFETY
SECTION 2
INTRODUCTION
This section summarizes general safety information for persons involved with the installation,
operation, and maintenance of heating, ventilating, and air conditioning (HVAC) equipment. Working
on HVAC systems means that you will encounter many potentially dangerous situations
involving:
• Equipment containing liquids and gases under pressure
SAFETY
• Energized electrical equipment
• Contact with extremely hot and cold equipment surfaces
• Rotating machinery
• Contact with chemicals and hazardous materials
• Installation and repair work involving movement of heavy objects
IT’S EVERYONE’S
RESPONSIBILITY
SAFETY MENU
Personal Safety
Personal Safety Equipment
Loose-Fitting Clothing and Jewelry Hazards
Lifting
Electrical Equipment
Electric Shock
Electrical Burns
Lock Out / Tagout
Mechanical Equipment
Rotating and Moving Parts
Sharp Objects
Hot and Cold Surfaces and Work Areas
Refrigerant and Other Pressurized Gases
Exposure to Refrigerants
Refrigerant Containers
Other Pressurized Gas Hazards
Gas and Oil Heating Equipment
Gas Leaks
Oil Leaks
Standing Leak Test and Purging
Incomplete Combustion
Other Gas and Oil Heating Precautions
Installation Tool Use Precautions
Power Tools
Ladders and Scaffolding
Soldering and Brazing Equipment
Rigging Equipment
Extreme Hot and Cold Weather Precautions
Hot Weather Precautions
Cold Weather Precautions
General Safety Awareness
Hazard Communication Standard
Confined Spaces
Hazardous Waste Management
Summary of Dangers, Warnings, Cautions, and Safety Instructions
SAFETY
Table of Contents
Map
Section Topics
Only trained and qualified service personnel
should install or service HVAC equipment
(Figure 2-1). Untrained personnel may perform
basic maintenance tasks such as cleaning and
replacing filters with little supervision. However,
unfamiliar tasks must be performed by (or under the supervision of) an experienced
technician.
The final responsibility for on-the-job safety
rests with you. Job and construction sites can
be hazardous places to work, but an awareness of the information provided in this section
will help you to avoid injuring yourself or damaging equipment. The safety instructions given
in this section and the remainder of this book
are general in nature and are not to be used as
a substitute for the manufacturer’s instructions.
No attempt should be made by anyone to install, operate, adjust, repair, or dismantle any
equipment until the manufacturer’s specific instructions have been read and are thoroughly
understood (Figure 2-2).
2
References
▼ Figure 2-1.
Always Learn New Skills Under the Supervision
of a Qualified Technician
▼ Figure 2-2.
Read and Follow Specific Instructions in the
Manufacturer’s Literature
PERSONAL SAFETY
Personal Safety Equipment
Many on-the-job injuries occur because work- ▼ Figure 2-3.
HVAC Technician Wearing Safety Glasses and
ers do not use personal protective equipment
Gloves
(Figure 2-3). The exact type of personal safety
equipment depends on the potential hazards
involved and on the local and/or Occupational
Safety and Health Administration (OSHA) rules
that apply to the job site. The most common
items of personal safety equipment you will use
as an HVAC technician are:
• Hard hat – Protects head from hard blows
and falling objects.
• Safety glasses or goggles – Protect eyes from flying objects or chemical splashes.
• Gloves – Protect hands from cuts, scrapes, burns, and chemical or refrigerant spills.
• Safety shoes – Protect feet from falling objects and prevent sharp objects from puncturing the
foot.
• Ear plugs/muffs – Protect ears from exposure to high noise levels.
• Respirator – Protects against breathing hazards or suffocation that might occur in the presence
of certain refrigerants or other gases.
• Safety harness/lanyard – Prevents falls when working more than six feet above the ground or
near deep holes.
To ensure that safety and protective equipment provides the intended protection, it should:
• Be inspected regularly.
• Be cared for properly as directed by the manufacturer’s instructions.
• Be used properly, when needed, as directed by the manufacturer’s instructions.
• Never be altered or modified in any way.
SAFETY
Table of Contents
Map
References
Section Topics
Loose-Fitting Clothing and
Jewelry Hazards
Rings or other jewelry, neckties, cloth gloves,
or loose-fitting clothing must not be worn when
working around equipment with rotating or
moving components. Motors that drive fans,
compressors, and pumps are an example. If
jewelry or clothing becomes caught in a motor
drive pulley or coupling, severe injury could occur. Rings or watches must not be worn when
working around energized electrical equipment
(Figure 2-4). Contact between the jewelry and
an energized circuit may result in electric shock,
injury, or death.
2
▼ Figure 2-4.
Remove Watches and Other Jewelry Before
Installing or Servicing Equipment
Lifting
Lifting or moving heavy objects causes many
injuries. Lift with your legs rather than your back,
because your leg muscles are stronger. When
lifting heavy objects, wear a back support belt
or similar device for added protection from injury. Use the following procedure to lift heavy
objects (Figure 2-5).
• Move close to the object to be lifted.
• Squat down. Keep your back straight and
your chin tucked in. Position one foot behind
the other with the forward foot at the side of
the object.
• Grip the object from underneath using whole
hands (not just fingertips), wrap your arms
around it, or use lifting handles when provided.
• Draw the object close to your body.
• Lift the object by slowly straightening your
legs. Keep the weight centered over your legs
as much as possible. If possible, pick the
object up in the direction of travel to avoid
twisting your back or knees.
▼ Figure 2-5.
How to Lift Safely
ELECTRICAL EQUIPMENT
When working on electrical equipment, always
observe the precautions in the service literature, on tags, and on labels attached to or
shipped with the unit. Perform all work to meet
the local and national electrical codes. For additional guidance, refer to the current issue of
the National Electrical Code® (NEC®).
Electricity can be dangerous, but if you develop the proper safety attitude about working
with it, you should have no problems. Working
on HVAC equipment involves working near exposed electrical components and/or
conductors. This can expose you to the potential hazards of electric shocks and burns.
QUICK NOTE
If an object is too heavy to lift
comfortably, ask for assistance or use
a hoist or other lifting device.
Remember, it is a lot easier to ask for
help than it is to nurse an injured
back!
SAFETY
Table of Contents
Map
2
References
Section Topics
Electric Shock
Electric shock happens when electrical current
flows through your body. It can damage your
heart by causing it to beat erratically or it might
even cause it to stop, resulting in death. High
voltage levels, such as 120 volts AC or 240 volts
▼ Figure 2-6.
AC, are always dangerous. However, even low
Both High and Low Voltages can be Dangerous
voltages can be lethal (Figure 2-6).
Many technicians think of DC voltages as low
BE CAREFUL!
and relatively safe. In most cases, this is true.
• HIGH VOLTAGE IS ALWAYS DANGEROUS.
However, you can encounter high DC voltage
• EVEN 40 VOLTS CAN BE LETHAL IF SKIN
in HVAC equipment that can be quite dangerIS WET OR DAMAGED.
ous. Exercise caution in these situations.
Usually, the high resistance presented by the
human body will prevent harm from low voltage. However, when skin is moist, or damaged
as from a cut, the resistance of your body is
greatly reduced. Under such conditions, even
40 volts or less can present a hazard. To prevent shocks, bodily contact between live (hot)
circuits or a live circuit and ground must be
avoided.
Circuit breakers with built-in ground fault circuit interrupters (GFCI) may be used to protect
HVAC equipment. These circuit breakers pro- ▼ Figure 2-7.
Portable Ground Fault Circuit Interrupter (GFCI)
tect the equipment from current overload. They
Module
also help to protect individuals against shock.
The GFCI device in the circuit breaker can detect a small current leak to ground, causing the
circuit breaker to trip and open the circuit. Such
a leak may not be detected by a conventional
circuit breaker.
Portable, plug-in GFCI devices like the one
shown in Figure 2-7 are available that turn a standard utility outlet receptacle into a GFCI-protected
circuit. GFCI-protected extension cords are also
available. Use them for added protection against
potential shock from an electrically-shorted power
120V
60Hz
tool.
Electrical shock can result from using defective and/or improperly grounded power tools or
from connecting power tools to improperly
grounded utility circuits. Use only approved
tools, equipment, and safety devices. Before
use, always make sure that all tools, equipment,
and safety devices are working properly and
are in good condition.
When using tools or extension cords that have three-prong plugs, never remove or alter the
grounding prong on the three-prong plug in order to insert it into a two-prong electrical utility
outlet. If you must connect equipment to a two-prong outlet, always do so using an approved
adapter with a green grounding lug. Make sure you connect the adapter grounding lug to a known
ground such as a properly grounded outlet box. Since many outlet boxes are not properly grounded,
always use a multimeter to verify that a good ground connection exists.
TEST
FAULT
RESET
Electrical Burns
Electrical energy can pass for short distances through air. When it does, the arc and flash can
cause burns, fires, and even explosions. Burns resulting from electrical arcs, such as in a short
circuit to ground, can be extensive and deep. More serious burns can even result in amputation of
the affected limb.
SAFETY
Table of Contents
Map
References
Section Topics
Lock Out/Tagout
Whenever possible, shut off electrical power at
the disconnect or service entrance panel before working on HVAC equipment. As shown in
Figure 2-8, the disconnect or panel should be
locked in the off position with a padlock and
tagged (lock out/tagout) to make others aware
that service is in progress. Never assume that
the equipment is “dead.” Use a meter to
verify it.
If you must perform a test with power applied, do not wear rings, watches, or other metal
jewelry. Follow the safety guidelines listed below when you must work on equipment with the
power on:
• Have only one hand in the unit.
• Avoid working in wet or damp conditions.
• Avoid working in poor light or when tired.
• Unless required by the manufacturer’s service procedure, do not bypass safety devices
such as door interlock switches.
• Make sure all grounds are connected properly.
• Use tools with insulated handles.
MECHANICAL EQUIPMENT
Rotating and Moving Parts
Equipment should not be operated without the
coupling or belt guards installed, even if for only
a short interval such as when checking motor
rotation.
When servicing equipment, guards should
not be removed from the equipment until it is
deenergized, locked out, and tagged
(Figure 2-9). After removing electrical power
from a unit, never attempt to service it until all
rotating and moving parts have come to a complete stop (Figure 2-10). Never try to stop a
coasting motor or fan blade. If you grip the motor
shaft, belt drive, pulley, or blades, the momentum can dismember or cut your hand severely
or pull your hand into the rotating mechanism.
Loose hardware thrown from a rotating component can be deadly. All set screws and other
attaching hardware must be tightened to specifications before starting a motor or other moving
part. It is a good practice to tighten all coupling
bolts twice to be sure that none have been overlooked.
2
▼ Figure 2-8.
Lock Out/Tagout Equipment Disconnect Switch
DANGER
▼ Figure 2-9.
Deenergize, Lock Out, and Tag Equipment Before
Removing Guards to Service Rotating
Components
▼ Figure 2-10.
Never Attempt Service Until all Rotating and
Moving Parts have Stopped
GRILLE REMOVED
Sharp Objects
Contact with sharp metal edges and other objects can cause injury. Be careful to avoid such
contact when removing or replacing parts.
Hot and Cold Surfaces and Work
Areas
Contact with hot surfaces can burn your skin
and leave permanent scars. These surfaces include: furnace burners, heat exchangers, flues,
electric heating elements, compressors, motors, and refrigerant lines.
QUICK NOTE
Even equipment that appears familiar
may have special model differences
from year to year. NEVER ASSUME
ANYTHING! Always review and follow
the manufacturer’s instructions when
installing or servicing any equipment.
SAFETY
Table of Contents
Map
Section Topics
2
References
Take care when soldering or brazing. High heat is present in the torch flame and the area
surrounding the parts being soldered or brazed. When soldering or brazing, keep a fire extinguisher close by and know how to use it. Also, avoid wearing clothing made from manmade
materials such as polyester because these materials can turn into molten plastic should a flame
accidentally come in contact with the clothing.
Cold surfaces can be as harmful as hot ones. Contact with extremely cold metal surfaces can
result in frostbite or other injury. Frostbite can also result from prolonged exposure to cold when
working outdoors or inside a freezer or cold storage room.
REFRIGERANT AND OTHER PRESSURIZED GASES
Exposure to Refrigerants
Gloves and safety glasses must be worn when working with refrigerants. Avoid getting refrigerant
on the skin or into your eyes. When accidentally released to the atmosphere, refrigerant can
cause frostbite or burn the skin.
All refrigerants can cause suffocation if the concentration and time of exposure are great enough.
Always provide adequate ventilation when working with refrigerants. Refrigerant vapor is invisible, usually has little or no odor, and is heavier than air. Therefore, be especially careful of low
places where it might accumulate.
Equipment rooms or other areas with large machines holding large amounts of refrigerant must
have alarm systems which detect small amounts of leakage and sound an alarm. Refrigerants
increase dramatically in toxicity when exposed to an open flame or a hot surface. Self-contained
breathing apparatus must be available outside the equipment room or other area containing large
equipment in case leakage occurs and entry into the contaminated area becomes necessary.
Some equipment rooms have a mechanical ventilation system to clear contaminated air from the
room.
Refrigerant Containers
▼ Figure 2-11.
Refrigerant Containers
See Figure 2-11. Low-pressure refrigerants
CFC-11, CFC-113, and HCFC-123 come in
Color Codes
NOTE:
standard steel drums or cylinders. Their boilRETURNABLE CONTAINERS
HFC-134a
CFC-11
Light Blue
Orange
ARE REFILLABLE BUT THIS IS
ing point is close to, or slightly above, ambient
USUALLY DONE AT THE FACTORY.
HFC-407C
CFC-12
Rust
White
temperature. The pressure they exert on the
HFC-410A CFC-113
Pink
Dark Purple
container is much less than that of medium and
RETURNABLE
HCFC-22
CFC-500
high-pressure refrigerants such as CFC-12,
Green
Yellow
HCFC-123 CFC-502
HCFC-22, HFC-134a, HFC-407C, HFC-410A,
Grey
Purple
CFC-500, and CFC-502. These refrigerants are
RECOVERY CYLINDERS
ARE REFILLABLE
liquefied compressed gases. If improperly
handled, the pressurized containers that hold
these refrigerants can burst or leak, causing
DISPOSABLE
damage, injury, or even death.
REFILLABLE
Medium and high-pressure refrigerants come
in either returnable or disposable metal containers which vary in shape and size. They
range in capacity from about one pound of refrigerant to 1,000 pounds or more. Do not
➧ CAUTION
reuse disposable (nonreturnable) containers nor attempt to refill them. Disposable
containers are made from common steel, which
can rust. Rust weakens the container walls and
seams so that they can no longer hold pressure and contain gases. Disposable cylinders
should be stored in dry locations to prevent rusting, and transported carefully to prevent
abrasion of their painted surfaces. Keep disposable containers in their original cartons as
an added measure of protection.
Refillable refrigerant containers must not be filled with more than 80% liquid. Never exceed
their rated capacity in pounds as expressed by the net weight on the cylinder label. Be sure to
take into account the container weight (“tare lbs.”) when estimating the net weight of refrigerant in
a cylinder. Excess liquid in a cylinder causes hydrostatic pressure that can result in an explosion.
Hydrostatic pressure increases rapidly with even small changes in temperature.
SAFETY
Table of Contents
Map
References
Section Topics
NEVER HEAT A CYLINDER WITH AN OPEN
FLAME OR PLACE AN ELECTRIC RESISTANCE HEATER IN DIRECT CONTACT WITH
IT. If it is necessary to warm a cylinder, do it
gradually and evenly with warm water
(Figure 2-12). Do not exceed 125° F on any
part of the cylinder.
Always double check to be sure you are using the proper refrigerant. The containers are
color-coded and are also labeled to identify their
contents. Container labels also include product, safety, and warning information.
Technical bulletins and Material Safety Data
Sheets (MSDSs) available from the manufacturers provide information important to your
health and safety. They describe the flammability, toxicity, reactance, and health problems
that could be caused by a particular refrigerant
if spilled or incorrectly used.
In addition to the precautions described
above, follow these rules when handling and
using refrigerant containers (Figure 2-13):
• Do not drop, dent, or abuse refrigerant containers. Do not tamper with safety devices.
• Always use a proper valve wrench to open
and close the valve.
• Replace the valve cap and hood cap to protect the cylinder valve when not in use or
empty.
• Secure containers in place to prevent them
from becoming damaged from moving
around, especially in a van or truck. Strap or
chain cylinders in an upright position.
• Do not store containers where the temperature can exceed the cylinder relief valve
settings.
• Do not mix refrigerants.
➧ WARNING
▼ Figure 2-12.
Warming Cylinder with Warm Water
WARM WATER
DO NOT EXCEED 125 F ON ANY
PART OF THE CYLINDER
▼ Figure 2-13.
Refrigerant Container Safety
REPLACE
VALVE CAP OR
HOOD CAP
WHEN NOT IN USE
STRAP OR
CHAIN IN AN
UPRIGHT POSITION
• DO NOT DROP, DENT, OR
ABUSE CONTAINERS
• ALWAYS USE THE PROPER
VALVE WRENCH
• PROTECT AGAINST HIGH
TEMPERATURES
Other Pressurized Gas Hazards
Nitrogen, oxygen, acetylene, and LP gases are
commonly used when installing or servicing
HVAC equipment. These gases are compressed and shipped under medium to high
pressures in cylinders. Because their use is so
common, technicians often get careless about
handling them.
Nitrogen – Nitrogen is supplied in cylinders at
pressures of about 2,000 psi. These cylinders
must not be moved unless the protective caps
are in place. Dropping a cylinder without the
cap installed may result in breaking the valve
off the cylinder. This allows the pressure inside
to escape, causing the cylinder to propel like a
rocket (Figure 2-14). Store nitrogen cylinders
in an upright position and away from all flammable and combustible materials.
Because of the high pressure, a gaugeequipped pressure regulator must be used on
the nitrogen tank (Figure 2-15). In addition, a
relief valve must be installed in the pressure
feed line to limit the pressure to a safe level for
use in the equipment being serviced.
NEVER CONNECT BOTH A REFRIGERANT
CYLINDER AND A REGULATOR-EQUIPPED
NITROGEN CYLINDER TO THE EQUIPMENT
AT THE SAME TIME BECAUSE THE HIGHER
PRESSURE NITROGEN CAN CAUSE THE REFRIGERANT CYLINDER TO EXPLODE.
2
▼ Figure 2-14.
A Compressed Gas Cylinder Becomes a
Dangerous Projectile if the Valve is Broken Off
▼ Figure 2-15.
Gauge-Equipped Pressure Regulator Used with
Nitrogen
TESTING
PRESSURE
GAUGE
CYLINDER
PRESSURE
GAUGE
➧ WARNING
PRESSURE
RELIEF
VALVE
CYLINDER
SAFETY
VALVE
NITROGEN
CYLINDER
PRESSURE
REGULATOR
CONNECTED
TO GAUGE
MANIFOLD
SET
HAND
VALVE
SAFETY
Table of Contents
Map
References
Section Topics
Oxygen – Like nitrogen, oxygen is supplied in
cylinders at pressures of about 2,000 psi. When
handling oxygen cylinders, follow the same precautions as for handling nitrogen cylinders.
Oxygen can cause ignition even when no
flame or spark is present, especially when it
comes into contact with oil or grease
(Figure 2-16). OXYGEN MUST NEVER BE
USED TO PRESSURIZE A SYSTEM SINCE AN
EXPLOSION HAZARD EXISTS WHEN OIL
AND OXYGEN ARE MIXED. Never handle oxygen cylinders with oily hands or gloves. Keep
oil and grease away from the cylinders and cylinder attachments or valves. Store oxygen in
an upright position and away from all flammable
and combustible materials, including gases like
acetylene. There should be a minimum of 20
feet separating oxygen cylinders from fuel cylinders in storage, or they must be separated by
a 1/2-hour minimum fire-rated wall that is at least
five feet high. Never use an oxygen regulator
for any other gas and never use a regulator for
oxygen that has been used for other service.
Acetylene – Acetylene cylinders are pressurized at about 250 psi. Even with its much lower
pressure, acetylene should be handled with the
same precautions as nitrogen and oxygen because acetylene is flammable. A
pressure-reducing regulator must be used and
set at a pressure of not more than 15 psig.
ACETYLENE BECOMES UNSTABLE AND
VOLATILE ABOVE 15 PSIG. The valve wrench
should be left in position on open acetylene
valves. This enables quick closing in an emergency. It is a good practice to open the
acetylene valve as little as possible, but never
more than 1-1/4 turns. Also, be sure not to use
a torch tip that will exceed the flow capacity of
the cylinder type (MC or B) being used. Use of
too large a tip can result in excess flow from
the cylinder, causing the tank absorbent (acetone) to be drawn from the cylinder and flow
into the regulator, hose, and torch. This can occur when small multiple-flame (rosebud) tips are
used with an MC cylinder or large rosebud tips
are used with a B cylinder.
Liquid Petroleum (LP) – LP gases such as
propane and butane are usually pressurized at
less than 300 psi and should be handled with
the same precautions as nitrogen and oxygen.
LP gas is heavier than air and explosive. It is
normally used as a fuel gas in furnaces. As with
the other gases discussed, a pressure-reducing regulator must be used. Gloves and safety
glasses must be worn when working with LP
gas. When accidentally released to the atmosphere, LP gas can cause frostbite or burn the
skin. Do not use pure LP gas in a furnace set
up for natural gas because an unsafe condition will be created. If using LP gas for soldering,
be sure not to turn the cylinder upside down.
This allows liquid fuel to flow into the torch and
may cause an explosion.
Figure 2-17 summarizes the cylinder pressures of common gases.
2
➧ WARNING
▼ Figure 2-16.
Oxygen Mixed with Oil can Cause an Explosion
OXYGEN
➧ WARNING
▼ Figure 2-17.
Cylinder Pressures of Common Gases
CONTENTS
UNDER
PRESSURE
GAS
NITROGEN
OXYGEN
ACETYLENE
LIQUID PETROLEUM
PRESSURE
2,000 psi
2,000 psi
250 psi
<300 psi
SAFETY
Table of Contents
Map
Section Topics
2
References
GAS AND OIL HEATING EQUIPMENT
When working on heating equipment, always observe the precautions in the service literature, on
tags, and on labels attached to or shipped with the unit. Perform all work to meet the local and national
gas or oil codes. For additional guidance, refer to the current issues of the National Fuel Gas Code
(NFPA No. 54/ANSI Z223.1) and/or the National Fire Protection Association Code.
Gas Leaks
Heating equipment can be hazardous due to the combustible fuels involved. Natural gas can be
dangerous because it can displace oxygen in the air and, if it accumulates, can be explosive. LP
gases are heavier than air and can collect in low places to form pockets of highly explosive gas.
All fuel gases have odorants added to make leak detection easier. If a leak occurs that causes
gas to collect inside a building, the following immediate actions must be taken:
• Clear the area of all occupants. Do not reenter until it is known to be safe.
• Notify the local gas utility.
• Shut off the supply of gas.
• Use every reasonable means to eliminate
sources of ignition. Do not operate electric ▼ Figure 2-18.
Never Use an Open Flame to Check for Leaks
switches. If lights are already turned on, do
not turn them off. If turned off, leave them
off.
• Ventilate the area by opening windows and
doors.
• Never use matches, candles, a flame, or
other sources of ignition to check for gas
leaks. Use a soap and water solution
(Figure 2-18).
• Use only a battery-operated flashlight or approved safety lamp when searching for the
leak.
Oil Leaks
Fuel oil on the floor or an accumulation in the
furnace combustion chamber are usually signs
of a leak. Leaking fuel oil in the presence of air
and an ignition source can result in a fire. As a
precaution to prevent leaks, compression fittings should not be used to pipe an oil-burning
system. Absorb and clean any oil spilled on the
floor with rags, absorbant, a suction pump, shop
vacuum, etc. (Figure 2-19).
Care should be taken not to start a furnace if
any oil has accumulated in the combustion
chamber. If oil has accumulated, shut off the oil
valves and vent the chamber. Turn off the electrical power. Remove the oil with a suction
pump.
If the puddle of accumulated oil is ignited, it
will burn intensely. You may not be able to extinguish the fire; it will have to burn itself out. If
this happens:
• Notify the fire department.
• Shut off the burner motor but allow the furnace fan to run to help dissipate the heat.
• Shut off the air shutter to reduce the air to
the burner.
• Let the fire burn itself out with reduced air.
▼ Figure 2-19.
Always Clean Up Oil Leaks Immediately
ABSORBANT
SAFETY
Table of Contents
Map
2
References
Section Topics
Standing Leak Test and Purging
OXYGEN MUST NEVER BE USED TO LEAK
TEST OR PURGE A GAS OR OIL FURNACE
PIPING SYSTEM SINCE AN EXPLOSION
HAZARD EXISTS WHEN OIL AND OXYGEN
ARE MIXED.
After the leak test of a gas furnace is completed, the gas trapped in the system should
be purged in a well-ventilated area to rid the
system of air or other gases. When doing so,
be careful not to purge the gas where it will collect in the furnace combustion chamber. After
purging, but before operating the unit, it is a
good practice to wait at least 5 minutes to allow any accumulated gas to dissipate. When
lighting the furnace pilot, never stand in front of
or look into the combustion chamber.
➧ WARNING
Incomplete Combustion
Only experienced technicians should make furnace combustion adjustments and then only as
directed by the manufacturer’s instructions.
Fuel and combustion air must be mixed safely.
Incorrect gas or oil pressure, wrong orifice type
or size, or improper burner position or adjustment can result in incomplete combustion. This
causes the furnace to produce aldehydes, soot,
and carbon monoxide (CO) gas (Figure 2-20).
Carbon monoxide gas is deadly. Prolonged
breathing of carbon monoxide can result in sickness or death. An inadequate supply of primary
or secondary air to the burners caused by some
restriction to airflow can cause flame rollout,
possibly starting a fire.
▼ Figure 2-20.
Incomplete Combustion
INCOMPLETE COMBUSTION CAN PRODUCE
Other Gas and Oil Heating
Precautions
In addition to the safety precautions discussed
above, observe the following guidelines when
CARBON
servicing gas and oil heating equipment:
SOOT
MONOXIDE ALDEHYDES
• Gas, oil, and electricity should be turned on
only when it is necessary to check the operation of a component or the furnace. At all
other times during equipment maintenance,
they should be turned off.
• Gas and oil furnaces should not be installed where flammable vapors or combustible materials
exist.
• Never operate a furnace with a corroded, pitted, or cracked heat exchanger. Leaking combustion gases may cause sickness or death.
• Do not jumper limit switches or other safety devices. These devices protect the furnace, building, and occupants from fire or damage caused by malfunctions that result in overheating.
• Gas and oil furnaces must be properly vented to avoid leaking carbon monoxide in the heated
area should the furnace combustion be incomplete. Also, any vent gases that leak into the
heated area will reduce the oxygen level.
• Be extremely cautious when working around energized pilot lights, electronic spark igniters,
and oil furnace ignition circuits. The control transformer secondary voltage and electrodes of
some ignition devices operate in the range of about 10,000 to 20,000 volts.
SAFETY
Table of Contents
Map
Section Topics
2
References
INSTALLATION TOOL USE PRECAUTIONS
Installation work requires that you take precautions to work safely with power tools and other
installation equipment while performing the various tasks.
Power Tools
The general safety procedures used when working with power tools are basically the same regardless of the tool being used. Safety begins by dressing properly and wearing safety glasses
and face and/or dust masks, if appropriate. Loose clothing and jewelry must be removed because
they can become caught in the moving parts of tools or equipment. Safety-type non-skid footwear
must be worn. Protective hair coverings must be worn to prevent long hair from becoming caught
in moving parts.
Before using a tool, inspect and check that ▼ Figure 2-21.
Inspect Tools Before Using
the guards are properly attached and make sure
that they operate properly and will work as intended (Figure 2-21). Check for alignment and/
or binding of moving parts, and any other condition that may affect operation. Always repair
or replace any damaged guard or other damaged part before using a tool.
Use the right tool (Figure 2-22). Do not use a
light-duty tool to do the job of a heavy-duty tool,
or use one for a purpose for which it was not
intended. The right tool will do a better job and
be safer to use.
NEVER OPERATE PORTABLE ELECTRIC
➧ WARNING
TOOLS IN EXPLOSIVE ATMOSPHERES
• ALL PROTECTIVE GUARDS ATTACHED AND WORKING
SINCE THE MOTORS IN THESE TOOLS
• CORRECT ALIGNMENT AND NO BINDING OF MOVING
NORMALLY GENERATE SPARKS WHICH
PARTS
CAN IGNITE ANY FUMES. Keep work areas
clean because clutter invites injury. Customers
▼ Figure 2-22.
and visitors should be prohibited from the imUse of the Right Tool is Safer
mediate work area to prevent accidents. Also,
dangerous practical jokes and horseplay must
be avoided because they can result in accidents
(Figure 2-23).
In addition to the precautions previously described, also follow these rules:
• Always operate the tool as directed in the
manufacturer’s instructions.
• Never carry a tool by its cord or yank the cord
NO
to disconnect it from a receptacle. Keep the
cord away from heat, oil, and sharp edges.
• Stay alert. Watch what you are doing and
use common sense. Do not operate a tool
when you are tired.
• Use clamps or a vise to hold the work. It is
YES
safer and it frees both hands to operate the
tool (Figure 2-24).
• Make sure to remove adjusting keys and
▼ Figure 2-23.
wrenches before turning the tool on.
Horseplay can be Dangerous
• Disconnect tools when not in use, before servicing, and when changing blades, bits, and
cutters.
• Prevent unintentional starting. Do not carry
tools plugged into electrical outlets with your
finger on the switch. Be sure the switch is
set to the OFF position before plugging a tool
into an outlet.
• Avoid overreaching by keeping proper footing and balance at all times while using the
tool.
• When using an extension cord outdoors, always use one approved for outdoor use.
SAFETY
Table of Contents
Map
2
References
Section Topics
Air-powered tools are sometimes used instead of electrical-powered tools for drilling and cutting jobs. When using air-powered tools, follow the same general safety practices as would be
used with the similar electrical tool. Before disconnecting the air supply hose from a tool, make
sure to first shut off the air supply and use the tool trigger to bleed off and vent the air in the hose.
Powder-actuated tools that use a gunpowder cartridge are sometimes used to drive fasteners
into steel or concrete. Because of the potential danger that the misuse of these tools may cause,
only trained and certified employees are permitted to operate these tools. Refer to Section 3 for
detailed information about powder-actuated tools, including any safety-related factors.
Ladders and Scaffolding
Before use, ladders should always be inspected
to make sure the rails, rungs, safety latches,
and feet are not missing, broken, damaged, or
loose. It is important that both straight and extension ladders be raised and placed at the
proper angle before climbing them
(Figure 2-25).
Once upright, raise the extended section to
the desired height, making sure that the safety
latches are engaged. Position the bottom of the
ladder so that the horizontal distance between
the ladder’s feet and the wall is about 1/4 the
ladder’s vertical height or working length, which
is the length of the ladder between the foot and
the top support (Figure 2-26). Both of the
ladder’s feet should be an equal distance from
the wall, so the ladder does not rock. If you are
going to step off the ladder onto a platform or
roof, the top of the ladder should extend at least
3 feet beyond the support point.
Once the ladder is in position, fasten and/or
block it securely at the top and bottom. Step
ladders should always be opened and set level
on all four feet, with the spreaders locked in
place (Figure 2-27). Never use a step ladder
like a straight ladder or stand on the top two
steps. For balance, lean your body into the ladder. When you can no longer reach your work
comfortably, get down and move the ladder.
Falls account for most of the accidents that
occur when working on ladders. To prevent falls
and other accidents, follow these precautions:
• Never use a damaged ladder or one with broken or missing rungs or steps. Any such
ladder should be removed from service.
• Barricade or put guards around a ladder that
is erected in doorways, passageways, or any
location where it can be jarred or knocked
over by others.
• When climbing up a ladder, keep both hands
on the rails and your body’s weight centered
between the rails.
• Face the ladder at all times when working
from it. If it is necessary to work backwards,
use a harness or safety belt with a lanyard.
• Do not carry tools or materials in your hands
while climbing a ladder. Haul them up or have
someone hand them to you.
• Never try to move a ladder while standing
on it.
• Do not use metal ladders near electric lines
or services.
• Never use a ladder as a scaffold by placing
it horizontally and standing on it. Ladders are
made for vertical use only.
▼ Figure 2-24.
Clamp Work and Use a Two-Hand Grip
QUICK NOTE
Only trained and certified persons
may operate explosive powderactivated tools. Certification is
established by the possession of an
accredited operator’s card.
▼ Figure 2-25.
Raising the Extension Ladder
▼ Figure 2-26.
Proper Positioning of an Extension Ladder
3 FEET
MINIMUM
FASTEN
SECURELY
VERTICAL
HEIGHT
1/4 VERTICAL HEIGHT
FASTEN SECURELY
SAFETY
Table of Contents
Map
References
Section Topics
Metal scaffolds may sometimes be used instead of ladders. When erected level and plumb
on a firm base, scaffolds provide a safe, secure elevated work platform. A green, red, or
yellow tag should be attached to any scaffold
that is assembled and erected to alert users of
its current mechanical and/or safety condition
(Figure 2-28). Do not rely solely on the tag. Inspect all parts of a scaffold before each use.
Handrails, toeboards, and decking must all be
in place, all wheels must be locked on movable models, and all locking pins must be
installed. Other precautions that must be taken
when working on scaffolds are:
• Never exceed the weight limit of the scaffold. This stated weight limit includes the total
weight of people, tools, equipment, and materials.
• Do not climb on or work from any scaffold
railing or brace members. Use a ladder to
get on the scaffold.
• Keep a minimum of 15 feet separation between the scaffold and any energized
electrical lines or equipment.
• Remove or secure all tools and materials on
a scaffold’s deck before moving the scaffold.
Do not ride on the scaffold when it is being
moved. Watch overhead clearances when
moving.
• If people can pass under the scaffold, screen
the space between the toeboard and top rail
to prevent tools and materials from falling off
the work platform.
• Do not use scaffold railings or braces for rigging.
2
QUICK NOTE
To ensure extension ladder strength
and your safety, keep a minimum
overlap between extended sections of
3 feet for 16- to 36-foot ladders; 4 feet
for 36- to 48-foot ladders; and 5 feet
for 48- to 60-foot ladders.
▼ Figure 2-27.
Position Step Ladder so Feet are Level on Floor
and Braces are Locked
PUSH SPREADERS
DOWN TO LOCK
▼ Figure 2-28.
Check Tags on Assembled Scaffolds
YELLOW
GREEN
RED
THIS SCAFFOLD DOES
LD
FFO
DO
SCA
THIS NOT U
NOT MEET
THIS S BEEN
SCA SE
FFO
HA CTED
LD
E
KEE
FEDERAL/STATE OSHA
ERR MEET
PO
THIS
SPECIFICATIONS
FF
SC
TO L/STATE S
EMPLOYEES WORKINGERECTE AFFOLD
ERA
ARD FROM THIS SCAFFOLD ONLYD OR TA IS BEIN
FED STAND FOR
G
AUTH KEN
MUST WEAR AND USE
EM
A
ORIZ DOWN
E
USIN PLOY
ED
OSH IS SAF ORK APPROVED
EE
PERS
G RE
S
AND RAFT W
FALL PROTECTION EQUI ONAL PRQUIRED
PMEN
C
OTEC
TER
ON
ALL
TIVE
THIS T MAY
T AL
O
DO N
DATE:
:
DATE
TION
/EREC
ENTER
CARP
SCAF WOR
FOLD K
DATE
:
CARP
MAN
FORE
ENTE
CARPENTER/ERECTION
CRAFT FOREMAN
R/E
CRAFT
RE
CTION
CRAF
T FO
REMA
N
TAGS SHOW MECHANICAL
AND SAFETY CONDITION
QUICK NOTE
SCAFFOLD TAGS
• Green Tag – Meets OSHA standards and is safe to use.
• Yellow Tag – Scaffold does not meet all OSHA standards. It can be used; however, it is mandatory
that the person using it wear and properly use a safety harness and lanyard fall protection gear.
• Red Tag – Keep off, the scaffold is damaged and unsafe, or in the process of either being erected
or taken down.
SAFETY
Table of Contents
Map
Section Topics
2
References
Soldering and Brazing Equipment
Soldering and brazing tasks normally involve the use of torches and accessories. The general
safety precautions described earlier in this section about the use and handling of pressurized
gases apply. The precautions given in Figure 2-38 at the end of this section also apply. Procedures for soldering and brazing, including safety factors, are provided in Section 5. The material
in both this section and Section 5 should be reviewed and understood before you attempt any
soldering and/or brazing tasks. Other precautions to take when using soldering and brazing equipment are:
• To extinguish any fires, always keep a fire
extinguisher within 25 feet of the work area.
• Use flame retardant shields to help protect
adjacent areas from flame and spark dam▼Figure 2-29.
age (Figure 2-29).
Use a Fire Retardant Shield to Protect the
• Wear protective gloves and use proper tools
Surrounding Area and Components from Flame
to handle hot work. When brazing, wear
and Spark Damage
goggles having an ANSI Z87.1 standard
shade No. 4 or 5 lens.
• Do not point the torch flame towards your
face or body or at other persons.
• Avoid getting flux on the skin or in the eyes.
Avoid inhaling soldering or brazing fumes.
Rigging Equipment
Rigging involves the movement of equipment
and materials using ropes, slings, cables, rollers, hoists, and cranes. It is necessary that you
be aware of rigging techniques and safety factors in order to prevent injury or damage to the
equipment. For safe rigging, the tools and
equipment used must be in good condition and
of the required strength to handle the load
(Figure 2-30).
Always refer to the manufacturer’s literature
to find the maximum weight of the equipment.
Always follow all warnings and cautions about
rigging and mounting of the equipment given
in the installation instructions and/or on instruction labels on the equipment.
General safety precautions for the use and
handling of rigging equipment and loads are
shown in Figure 2-40 at the back of this section. The material in both this section and
Section 4 should be reviewed and understood
before attempting any rigging tasks.
QUICK NOTE
• On sunny days, it may be difficult to
see the torch’s flame.
• On windy days, the torch’s heat may
be carried towards you or to areas
not intended to be heated.
▼ Figure 2-30.
Rigging Tools and Equipment Must be in Good
Condition and of the Strength Required to
Handle the Load
SAFETY
Table of Contents
Map
2
References
Section Topics
EXTREME HOT AND COLD
WEATHER PRECAUTIONS
Performing service or installation work outdoors
in extreme heat or cold requires that appropriate precautions be taken to prevent bodily injury
or illness.
QUICK NOTE
SYMPTOMS OF HEAT STROKE
• Sudden onset
Hot Weather Precautions
Heat stroke can result from heavy exertion in
high temperature and/or high humidity conditions. When working in these conditions, dress
in loose, cool cotton clothing and take periodic
breaks to avoid overexerting yourself.
Heat stroke can be life-threatening because
the body’s heat-regulating mechanism stops
working. This can cause convulsions, unconsciousness, and even death if the body is not
cooled quickly. If heat stroke occurs, do not
delay getting immediate medical attention
for the affected person. To help reduce the
body temperature, move the person to a cool
place and remove as much clothing as possible.
Douse the person with water or wrap him or
her in a wet sheet.
Heat exhaustion and heat cramps happen
when body fluids are lost through heavy sweating, but the sweat cannot evaporate fast enough
to cool the body. To help reduce body temperature, the affected person should be moved to a
cool place and clothing removed. Cramped
muscles can also be gently stretched and massaged. Give sips of salt water and get
immediate medical attention.
• Dry, hot, and flushed skin
• Dilated pupils
• Loss of consciousness
• Fast pulse
• Deep breathing at first, later shallow
or almost absent
• Muscle twitching
• Body temperature 105° F or higher
➧ CAUTION
SYMPTOMS OF HEAT EXHAUSTION/
HEAT CRAMPS
• Weak pulse
• Rapid and usually shallow breathing
• General weakness
• Pale, clammy skin
• Heavy sweating
• Dizziness, disorientation
• Slightly above normal body
temperature
• Painful muscle cramps
Cold Weather Precautions
Working in extremely cold weather requires that
you dress adequately to protect against the
cold. Dress in layers to allow you to adjust to
changing temperature conditions. Cotton or
lightweight wool should be worn next to the skin
with wool layers over the undergarments. Outer
garments should be waterproof and wind resistant. A hat with ear protection prevents heat
loss from the head. Waterproof boots should
be worn in wet or snowy weather.
The effects of hypothermia (low body temperature) are gradual, and often go unnoticed
until it is too late. It is recommended that a
buddy system be used when working in extreme
cold. If working alone, let someone know where
you will be and what time you expect to return.
Get immediate medical attention for hypothermia. Move the person indoors and remove
any wet clothing. If the person is conscious, give
hot liquids and/or a hot bath to speed up the
warming process.
The ears, nose, hands, and feet can be affected by frostbite. If affected by frostbite,
cover the frostbitten area to protect it and
get immediate medical attention.
QUICK NOTE
SYMPTOMS AND PROGRESSION OF
HYPOTHERMIA
• Shivering
• Slurred speech
• Mental confusion
• Drowsiness and weakness
• Glassy stare
• Respiration and pulse rate become
slower and slower
• Extremities freeze
• Death
➧ CAUTION
SYMPTOMS AND PROGRESSION OF
FROSTBITE
• Exposed skin reddens
• Skin takes on a gray or blotchy
➧ CAUTION
appearance, especially at the ear
lobes, cheeks, and tip of the nose
• Exposed skin surface becomes
numb
• All sensation is lost and the skin
becomes white
SAFETY
Table of Contents
Map
2
References
Section Topics
GENERAL SAFETY
AWARENESS
Hazard Communication Standard
The work place contains many hazards that
need to be recognized and respected
(Figure 2-31). The OSHA Hazard Communication Standard (HazCom), commonly called the
“Right To Know” requirement, affects every
worker. It addresses the worker’s right to know
the specifics about any major environmental,
chemical, biological, physical, or radiation hazards that may exist at the job site. It requires
that a Material Safety Data Sheet (MSDS) accompany every shipment of a hazardous
chemical or substance and be available to you
on the job site. It is your responsibility to:
• Read the Material Safety Data Sheets that
pertain to your work and work location to
identify any physical and health hazards.
• Know and practice the actions necessary to
protect yourself and others from any hazards.
Know the actions to take in an emergency.
• Spot and report potential hazards on the job.
▼ Figure 2-31.
Safety Depends on Your Awareness
Know:
• MSDS's
• Safety Practices
• Emergency Procedures
MSDS
• How to Spot and
Report Hazards
Confined Spaces
Installation and service work is not always done outside or in open areas. Much of it takes place
in confined spaces. A confined space is any area that cannot be easily ventilated, such as a
basement equipment room. Confined spaces can contain hazardous gases and/or fluids when
the equipment is operating. Work you are doing, such as soldering and brazing, may introduce
hazardous fumes into the space. To ensure safety, special precautions are needed before entering, and while working in, a confined space:
• Have one person inside and one outside the ▼ Figure 2-32.
Use Respiratory Equipment when Required
confined space. Voice or visual contact
should be maintained to identify the need for
aid in case of an emergency.
• Keep rescue equipment ready for an emergency.
• Use respiratory protection equipment when
required (Figure 2-32). If in doubt, have air
sample readings taken to check for low levels of oxygen and/or explosive gases.
• Use only approved electrical tools, extension
cords, etc.
Hazardous Waste Management
Waste such as used oil or refrigerant, chlorinated solvents, chemical treatment solutions, acids,
etc. may contain toxic components that require special handling and proper disposal at an EPAapproved waste management facility. When working with hazardous waste:
• Be knowledgeable about the use of chemicals from the Material Safety Data Sheets and follow
the manufacturer’s instructions.
• Wear the proper protective equipment, such as safety goggles, rubber gloves, and aprons
when handling or containing hazardous waste.
• Use only EPA/DOT-approved containers for storage, transport, and disposal of hazardous
wastes. Make sure the content of the container is identified by the proper EPA/DOT label
containing all the required information.
SAFETY
Table of Contents
Map
2
References
Section Topics
SUMMARY OF DANGERS,
WARNINGS, CAUTIONS, AND
SAFETY INSTRUCTIONS
The terms DANGER, WARNING, and CAUTION have specific meanings that have been
designated by the American National Standards
Institute (ANSI) to clearly identify the degree of
hazard. The definitions and color coding shown
in Figure 2-33 are typical of those used in the
HVAC industry to prioritize safety hazards.
Figures 2-34 through 2-41 shown in the remainder of this section are typical examples of
safety precautions and information you will see
both in equipment manufacturer’s Installation,
Start-Up, and Service literature and on equipment warning labels.
To avoid hazards and servicing mistakes, it
is a good practice to always review a procedure before doing it. This review makes you
aware of, and able to handle, all of the important safety conditions before you start.
▼ Figure 2-33.
Typical Terms Used to Prioritize Safety Hazards
!
DANGER
RED WITH
WHITE LETTERS
There is an immediate hazard which WILL result in severe
personal injury or death.
!
WARNING
ORANGE WITH
BLACK LETTERS
Hazards or unsafe conditions which COULD result in
severe personal injury or death.
!
CAUTION
Potential hazards or unsafe practices which COULD result
in minor personal injury or product or property damage.
YELLOW WITH
BLACK LETTERS
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-34.
Electrical Equipment Precautions
!
DANGER
DO NOT attempt to check voltage supplies until you know the proper procedures
and have the proper equipment. SEVERE PERSONAL INJURY CAN RESULT.
Consult your power company for specific instructions and obtain their services
when necessary.
DO NOT attempt to take measurements on high-voltage systems (600 volts or
over) with hand-held instruments. Always use current and potential transformers
to take high-voltage measurements.
DO NOT take measurements or make continuity checks on a compressor until you
are sure that ALL POWER IS TURNED OFF TO THE UNIT OR SYSTEM,
INCLUDING THE CRANKCASE HEATERS. When taking voltage, current, or
continuity measurements on a hermetic or semi-hermetic compressor in a pressurized
system, always take measurements at terminal boards and test points away from
the compressor, rather than at the compressor. If the compressor terminals are
damaged and the system is pressurized, disturbing them to take measurements
could cause them to blow out, causing injury. Once a system has been evacuated and
is no longer under pressure, measurements can be taken at the compressor. Check
the lockout and tagout of both electrical components and the compression system.
!
WARNING
DO NOT work on high-voltage equipment unless you are an experienced HVAC
technician qualified to maintain electrical equipment or a qualified electrician.
GROUND all electrical equipment.
USE a ground fault circuit interrupter with power hand tools.
DO NOT work on electrical components, including control panels, switches, starters,
or heaters until you are sure that ALL POWER IS OFF and no residual voltage can
leak from capacitors or solid-state components.
LOCKOUT AND TAGOUT electrical circuits before working on them. IF WORK
IS INTERRUPTED, confirm that the circuits are deenergized before resuming work.
DO NOT remove terminal box covers while machine or compressor is running.
DO NOT tighten any connection on a terminal board until the main disconnect
switch is in the OFF position and locked out.
DO NOT attempt to stop a machine by opening an isolating knife switch. High
intensity arcing can occur and cause serious injury.
NEVER USE an ohmmeter in any energized circuit. Destruction of the meter could
result in personal injury.
NEVER apply voltage to or operate a compressor when there is a vacuum in the
system. This can cause the compressor terminals to fail due to internal arcing which,
in turn, can result in severe personal injury.
NEVER energize a compressor until the discharge service valve is open to the
system. Failure to do so can result in excessive pressure buildup.
DO NOT exceed the manufacturer’s torque specifications when making electrical
connections. Terminal bolts could snap and propel from the terminal block.
!
CAUTION
BE AWARE that certain automatic start arrangements can engage the starter.
Open the disconnect and lock it out ahead of the starter in addition to shutting off
the machine or pump.
DO NOT bypass, block interlocks, or remove a lockout/tagout that is in place
unless it is yours.
MINOR SHOCKS can surprise you. While the shock itself would probably not
be injurious, a resulting fall could be.
DO NOT check a circuit until you are sure that the power is off in any adjacent
circuit.
2
References
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-35.
Gas and Oil Heating Equipment Precautions
!
WARNING
Improper installation, adjustment, alteration, service, maintenance, or use of
equipment can cause carbon monoxide poisoning, explosion, fire, electrical shock,
or other conditions which may cause personal injury or property damage. Consult
a qualified installer, service agency, local gas supplier, or your distributor or branch
for information or assistance. The qualified installer or agency must use only
factory-authorized and listed kits or accessories when modifying products. Failure
to follow this warning could result in electric shock, fire, personal injury, or death.
When a furnace is installed in a residential garage, it must be installed so that
burners and ignition sources are located a minimum of 18 in. above the floor. The
furnace must be located or protected to avoid physical damage by vehicles. When
a furnace is installed in a public garage, airplane hangar, or other building having
a hazardous atmosphere, the unit must be installed in accordance with the
requirements of the National Fire Protection Association Inc.
NEVER USE OXYGEN OR COMPRESSED AIR to leak test or purge gas or oil
furnace piping systems since an EXPLOSION HAZARD exists when oil and
oxygen are mixed. Follow the manufacturer’s recommendations for leak testing
or purging.
NEVER use matches, candles, flame, or other sources of ignition for the purpose
of leak detection. Use a battery-operated flashlight or approved safety lamp when
searching for the source of the leak. For gas leaks, use a soap-and-water solution
to check for leakage. Failure to follow this warning could result in fire, explosion,
personal injury, or death.
NEVER purge a gas line into a combustion chamber. Failure to follow this warning
could result in fire, explosion, personal injury, or death.
Use the proper length of pipe to avoid stress on the gas control manifold. Failure
to follow this warning could result in a gas leak resulting in fire, explosion, personal
injury, or death.
2
References
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-36.
Leak Testing and Pressure Testing Precautions
!
DANGER
NEVER USE OXYGEN to leak test, purge lines, or pressure test a machine.
Nitrogen is recommended for these purposes. Always use a gauge-equipped
regulator on the nitrogen cylinder and verify that the gauge has been recently
checked and calibrated.
The full pressure of a nitrogen cylinder can cause a refrigerant cylinder
to rupture violently. Therefore, when using nitrogen and a refrigerant
trace for leak testing, always put the refrigerant in first. Then valve off
and remove the refrigerant cylinder before connecting and adding the
regulated nitrogen.
NEVER EXCEED the specified field leak test pressures. Verify the allowable field
test pressure by checking the instruction literature.
Do not allow the full cylinder pressure to enter a pressurizing line.
Valve off and disconnect the nitrogen cylinder when the recommended
test pressure is attained. Do not rely on the shutoff valve or pressure
regulator.
Do not pressure test any vessel at its design pressure (found on the
equipment nameplate). Testing at these pressures must be done in a
special enclosure or by using a hydraulic fluid under the direction of
the manufacturer.
Do not confuse water (brine) side test pressures with refrigerant side
test pressures.
HEAVY CONCENTRATIONS of nitrogen within a confined space or area can
displace enough oxygen in the work area air to cause suffocation.
DO NOT enter any vessel or confined space immediately after the use of significant
amounts of nitrogen without the protection of SCBA or first testing the oxygen
level. Utilization of respiratory protection should not be needed if adequate
ventilation of the space is allowed to occur prior to entry and the oxygen level has
been tested and is above 19.5 percent.
2
References
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-37.
Mechanical Equipment Precautions
!
DANGER
DO NOT remove coupling (or belt) guards to work on a machine until all rotating
parts have come to a complete halt.
MACHINES MUST BE locked out and tagged out regardless of the type of energy
powering the equipment.
NEVER ENTER an enclosed fan cabinet or reach into a unit while the fan is running.
NEVER use a torch to remove a compressor or component from the refrigerant
circuit. The oil could ignite and cause a fire. Use a pipe cutter and follow correct
procedures when cutting refrigerant lines.
!
WARNING
NEVER OPERATE an open-drive machine, pumpout unit, or other equipment
without coupling (or belt) guards in place. This warning applies even to short runs
such as a motor rotation check. Serious injury can result from contact with moving
parts.
NEVER loosen any head or cover bolts when the compressor is open to the system
or when it is under pressure. Make sure the internal pressure is at 0 to 2 psig before
any bolts are loosened to prevent propulsion of compressor parts.
DO NOT attempt to remove fittings and covers or break lines while the machine
is under pressure or while it is running.
USE CARE when working near or in line with a compressed spring. Sudden release
of the spring can cause it and objects in its path to act as projectiles.
DO NOT syphon refrigerants or other chemicals by mouth. Check the manufacturer’s
instructions for correct syphoning procedures.
!
CAUTION
DOUBLE CHECK that coupling nut wrenches, dial indicators, or other items have
been removed before rotating any shaft. Remember to wear safety glasses.
PERIODICALLY INSPECT couplings for proper lubrication and alignment to
minimize the possibility of failure and resultant flying particles.
TIGHTEN all coupling bolts twice to be sure that none have been overlooked.
CHECK coupling locknuts for tightness and for insertion of setscrews.
DO NOT weld or flamecut any vessel or line until all refrigerant has been removed.
DO NOT loosen a packing gland nut before making sure that it has a positive thread
engagement.
PERIODICALLY INSPECT all valves, fittings, and piping for corrosion, rust,
leaks, or damage.
VALVE OFF AND TAG steam, water, and refrigerant lines before opening them.
DO NOT step on refrigerant lines. Broken lines can whip about and cause severe
personal injury.
USE only repair or replacement parts that meet the code requirements of the original
equipment.
2
References
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-38.
Oxyacetylene Welding and Cutting Precautions
!
DANGER
DO NOT use oxygen as a substitute for compressed air, or for any purpose other
than welding or flamecutting.
!
WARNING
DO NOT store oxygen cylinders near combustible material, especially oil and
grease, nor handle oxygen cylinders or apparatus with oily hands or gloves.
Oxygen supports and accelerates combustion and will cause oil, grease, and plastic
materials to burn with great intensity.
DO NOT weld or flamecut near combustible materials, nor in an atmosphere
containing refrigerant, nor until pressure vessels and piping have been completely
evacuated.
DO NOT weld or flamecut in a confined area unless the area is adequately ventilated.
Where it is impossible to provide adequate ventilation, wear SCBA and have
another person on standby immediately outside the confined area.
DO NOT carry a plastic liquid-fuel cigarette lighter or other flammable materials
while welding, soldering, or brazing. Welding sparks, molten metal, and heat from
a torch can ignite the contents of the lighter and cause it to explode.
!
CAUTION
DO NOT store oxygen and fuel gas cylinders near any heat source nor adjacent
to each other.
STORE oxygen and fuel gas cylinders in an upright position and strap securely
in place.
WEAR flame-retardant protective clothing and equipment when welding and
flamecutting, and when in the vicinity of such operations.
DO NOT block passageways, ladders, and stairways with welding equipment.
Use effective safeguards when working on platforms, scaffolds, or runways
including safety belts and safety lines when necessary.
SAFETY INSTRUCTIONS
Observe the color coding of pipelines, cylinder, and hoses. Double check the code by
reading all labels.
Do not use defective hoses.
Do not tape more than 4 inches out of every 12 inches when taping parallel sections
of fuel and oxygen hose.
Do not use connectors other than those made especially for acetylene welding and
cutting equipment. Make sure all connections are tight.
Do not fail to crack the cylinder valve before attaching the regulator.
Release the regulator adjusting screw before opening a cylinder valve.
Stand to one side when opening a regulating valve.
Before each use, inspect torches for leaking shutoff valves and tip connection.
Do not use a defective torch.
Ignite torches by friction lighters only.
Customer requirements and construction work sites may or could specifically require
utilization of safety equipment such as hard hats, gloves, goggles, safety glasses, safety
shoes, respirators, etc. Be prepared by having these items safely stored in a clean and
secure compartment of the service vehicle, readily available for use when necessary.
2
References
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-39.
Personal Protection Precautions
!
WARNING
WEAR a hard hat wherever there is potential danger from falling or flying objects.
DO NOT touch electrical equipment if your hands are wet or if you are standing
on a wet surface.
DO NOT look at arcs or other welding processes, regardless of distance, without
appropriate eye protection.
DO NOT carry or use a plastic liquid-fuel cigarette lighter or other flammable
materials when in the vicinity of welding operations. Sparks from a welding torch
can ignite the lighter and cause it to explode.
Safety shoes, hard hats, and safety glasses are required at construction job sites.
!
CAUTION
DO NOT WEAR:
• Rings or other jewelry, long ties, gloves, or loose clothing when working
around moving machinery.
• Rings or watches when working around electrical equipment.
WEAR:
• Safety glasses with side shields and safety shoes before entering construction
sites or manufacturing areas.
• Goggles and gloves when handling chemicals; welding helmets when
welding, cutting, brazing, or grinding; and when in the vicinity of these
operations.
• Gloves before touching any part of a machine that is operating or one that has
recently been shut down. Assume that the metal is hot!
• Gloves when handling machinery components after a major failure; e.g., after
a motor burnout: not only the refrigerant but also the oil will be acidic.
• Gloves and coveralls when working with or around sheet metal.
• Hearing protection in areas where sound levels exceed 90 dBA.
• Safety shoes, or specially treated shoes when necessary to protect against
corrosive chemicals.
• Flame-retardant protective clothing suitable for the type of welding being
done.
2
References
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-40.
Rigging Precautions
!
DANGER
DO NOT use cranes under power lines.
Obtain assistance from a utility company as necessary.
Damaged or defective equipment or equipment that does not have load capacity
information shall be taken out of service.
Alloy 80 chain is the only type recommended for maintenance and servicing
operations.
!
WARNING
CHECK the manufacturer’s drawings and service instructions for assembly or
component weights to be sure they can be handled safely by the rigging equipment.
CHECK the centers of gravity and note any specific rigging instructions.
DO NOT use other than OSHA-approved rigging equipment and methods.
INSPECT all rigging equipment prior to use to be sure it is in good condition and
has load limit ratings on it.
DO NOT use eyebolt holes to rig an entire assembly, nor use eyebolts to rig a
compressor.
DO NOT move a loaded crane, hoist, or chain fall until you are sure there is no
obstruction or personnel in its path and have determined that the unit will remain
stable and upright.
Safety shoes are recommended when working with rigging, gantries, and hoists.
!
CAUTION
USE MECHANICAL EQUIPMENT (chain fall, hoist, etc.) to lift or move the
inspection covers or other heavy components. Even if the components are light,
use such equipment when there is a risk of slipping, losing your balance, or injuring
your back.
DO NOT climb over a machine or fan cabinet; use platforms, catwalks, or staging.
LOOK for objects on the floor or slippery areas that could cause falls.
SAFETY INSTRUCTIONS
FOLLOW safe practices when using OSHA-approved ladders.
Use lifting lugs, where provided, in accordance with each rigging instruction.
Be aware of the location of your fellow workers at all times.
2
References
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-41.
Refrigerant Precautions
!
WARNING
NEVER APPLY an open flame or live steam to a refrigerant cylinder. When it is
necessary to heat the refrigerant, use warm (110° F/43° C) water.
DO NOT STORE refrigerant cylinders where the surrounding temperature can
exceed the relief valve setting. When this is not possible, use a water shower or
similar type cooling.
SLOWLY OPEN charging and regulating valves to prevent overpressurizing.
ALWAYS USE the proper valve wrench to open and close valves. Loosen the packing
nut before turning on the valve; retighten the nut after closing the valve.
NEVER FORCE connections.
DO NOT REUSE disposable (nonreturnable) cylinders nor attempt to refill them.
IT IS DANGEROUS; it is also illegal. When a cylinder is emptied, bleed off the
remaining gas pressure, loosen the collar, and unscrew and discard the valve stem.
DO NOT INCINERATE.
ALWAYS leave room for expansion when filling a refrigerant cylinder. Hydrostatic
pressure increases rapidly with even a small change in temperature.
DO NOT tamper with safety devices.
Use appropriate equipment to move refrigerant cylinders, such as hand trucks,
dollies, etc.
!
CAUTION
ALWAYS REPLACE the valve and hood caps when a cylinder is not in use or is
empty.
DO NOT alter cylinders.
DO NOT dent, drop, or abuse refrigerant cylinders.
SECURE all refrigerant cylinders, whether full or empty, in an upright position
with a strap or chain.
AVOID pressure surges when transferring refrigerant. Use a pressure regulating
valve to make gradual adjustments. The pressure relief valve device on a cylinder
cannot protect against an instantaneous pressure surge.
NEVER charge a refrigerant cylinder beyond the weight marked on the cylinder.
DO NOT depend on the color of a cylinder for identification of the refrigerant;
read the label.
INSPECT hoses, manifolds, and fittings regularly and keep them in good condition.
DO NOT USE damaged or defective equipment.
2
References
SAFETY
Table of Contents
Map
Section Topics
▼ Figure 2-41.
Refrigerant Precautions (Cont.)
!
WARNING
DO NOT enter and perform work inside any vessel without proper respiratory
protection and a second person on standby outside the vessel (the buddy system).
DO NOT enter any equipment room or space containing air conditioning or
refrigeration machinery after a known refrigerant spill until you are using a selfcontained breathing apparatus (SCBA) and are using the buddy system.
AVOID spilling liquid refrigerant on the skin or getting it into your eyes. USE
SAFETY GOGGLES. Wash any spills from the skin with soap and water. If any
refrigerant enters the eyes, IMMEDIATELY FLUSH EYES with water and consult
a physician.
!
CAUTION
DO NOT weld or flamecut in an atmosphere containing refrigerant vapor until the
area has been well ventilated.
DO NOT weld or flamecut any vessel or refrigerant line until the refrigerant has
been removed.
AVOID breathing refrigerant fumes.
DO NOT smoke in an atmosphere containing refrigerant vapor.
Refrigerants are heavier than air and water and will settle in all low places.
RESPIRATORY PROTECTION such as SCBA may be necessary for entry into
and work within areas where a spill has occurred.
2
References
INSTALLING FASTENERS AND ANCHORS 3
▼ INSTALLING FASTENERS AND ANCHORSS
SECTION 3
INTRODUCTION
A variety of mechanical fasteners such as nails, screws, and anchors are used when installing
HVAC equipment. Use of the wrong fasteners or improper installation of fasteners can cause
injury to people, damage to the equipment, or both. For these reasons, the HVAC installation
technician must know the capabilities of fasteners, be able to select the correct kind for the job,
and install them properly.
FASTENERS AND ANCHORS MENU
Nails
Screws
Hammer-Driven Pins and Studs
Powder-Actuated Drivers and Fasteners
Toggle Bolts
Masonry and Hollow-Wall Anchors
Self-Drilling, Snap-Off Anchors
Epoxy Anchoring Systems
Guidelines for Drilling Anchor Holes in Masonry
Machine Bolts, Screws, and Related Hardware
Machine Bolts, Screws, and Studs
Thread Designations
Fastener Grade Designations
Flat and Lock Washers
Nuts
Set Screws
Installing Threaded Fasteners
Torque Wrenches
Tightening Sequence and Torquing Guidelines
Keys
Blind (Pop) Rivet Installation
INSTALLING FASTENERS AND ANCHORS 3
Table of Contents
Map
References
Section Topics
NAILS
A wide variety of nails (Figure 3-1) are made
for fastening wood and other materials. Some
nails are made specifically to be driven manually with a hammer. Other specialized nails are
made to be driven by pneumatic or cordless
nailer tools.
Nail manufacturers label their boxes of nails
to identify their intended use. Refer to these
labels to pick the right nail for the job. The length
of a nail is stated by its penny size (d), where
8d identifies an 8 penny nail, 10d identifies a
10 penny nail, and so on. The larger the number, the larger the nail. Nailing rules of thumb
are:
• Select a nail three times longer than the material being fastened.
• Drive nails at an angle to increase holding
power.
• In hardwood or near the edges or ends of a
board, drill a pilot hole to prevent splitting or
the nail from bending.
• When fastening to metal, use nails made of
the same metal to prevent galvanic corrosion.
▼ Figure 3-1.
Nails
FRAMING (COMMON)
FLOORING
FINISHING
ROOFING
DRYWALL
MASONRY
QUICK NOTE
Pennyweight (d) is used to designate
the length of a nail from tip to head.
Nails are designated 2d (1 inch)
SCREWS
Screws (Figure 3-2) are made for fastening
materials where greater holding power is
needed than can be provided by nails, or where
nails are not appropriate. They are also used
to fasten materials that may need to be removed. Screws have heads with different
shapes and slots made to fit various kinds of
manual and power tool screw drives
(Figure 3-3). The size (diameter) of a screw’s
body or shank is given in gauge numbers ranging from No. 2 to No. 24, and in fractions of an
inch for screws with diameters larger than 1/4
inch. The higher the gauge number, the larger
the diameter of the shank. Screw lengths range
from 1/4 to 6 inches. Some guidelines for installing screws are:
• Always use a driver tip with the proper size
and shape to fit the screw.
• When possible, use screws long enough to
allow 2/3 of the screw length to enter the
piece that is being gripped.
through 16d (3-1/2 inches). Nails
above 16d are called spikes. Spike
sizes range from 20d (4 inches) to
60d (6 inches). The shank thickness
or gauge of a nail increases with the
length of the nail.
▼ Figure 3-2.
Wood, Drywall, and Masonry Screws
DRYWALL
FLAT SLOT
ROUND SLOT
FLAT PHILLIPS
FLAT PHILLIPS
HEX SLOT
WOOD
MASONRY
▼ Figure 3-3.
Screwheads and Screw Drives
OVAL
ROUND
FLAT
HEX WASHER
PAN
HEX
STAR
ONE-WAY
HEX
SLOTTED
PHILLIPS
ROBERTSON
(CROSS RECESS)
INSTALLING FASTENERS AND ANCHORS 3
Table of Contents
Map
References
Section Topics
Lag screws (Figure 3-4) or lag bolts are
heavy-duty wood screws that provide greater
holding power. They typically are used to fasten heavy equipment to wood, but can also be
used to fasten equipment to concrete if a lag
shield is used. A lag shield or expansion shield
is a lead insert that is placed in a pre-drilled
hole in the concrete. When a lag screw is
screwed into the lag shield, the shield expands
in the hole, firmly securing the lag screw.
Sheet metal screws (Figure 3-5) are threadforming or thread-cutting screws used to fasten
light-gauge sheet metal. Sheet metal screw
threads are deeper than those of wood screws
and extend the full length of the screw, which
allows the two pieces of metal being fastened
to be drawn tightly together directly under the
screw head. Because their deeper threads hold
better, sheet metal screws are also recommended for use with softer materials like
particleboard. Self-drilling sheet metal screws
are also available that drill, tap, and fasten in
one operation. Sheet metal screws are made
in similar diameters and lengths as wood
screws.
QUICK NOTE
• When drilling a clearance hole,
use a drill that has the same
diameter as the screw.
• When drilling a pilot hole, use a
drill that is smaller in diameter
than the screw.
▼ Figure 3-4.
Lag Screw and Lag Shield
LAG SCREW
LAG SHIELD
▼ Figure 3-5.
Sheet Metal Thread-Forming and Thread-Cutting
Screws
HAMMER-DRIVEN PINS AND
STUDS
Hammer-driven pins and threaded studs can
be used to fasten wood or steel to masonry without the need to pre-drill holes. The fastener is
inserted into a hammer-driven tool
(Figure 3-6). Then the tool’s drive rod is struck
using an engineer’s hammer, causing the fastener to be driven into the masonry.
QUICK NOTE
Make sure to use the proper size bit
when drilling pilot holes for use with
sheet metal screws. The correct drill
size is usually marked on the box
containing the screws.
▼ Figure 3-6.
Hammer-Driven Tool
HAMMERDRIVEN TOOL
FASTENERS
ENGINEER’S
HAMMER
INSTALLING FASTENERS AND ANCHORS 3
Table of Contents
Map
References
Section Topics
POWDER-ACTUATED
DRIVERS AND FASTENERS
Powder-actuated drivers (Figure 3-7) can be
used to drive specially designed fasteners into
masonry and steel. These drivers are fired like
a gun and use the force of a cartridge (typically
22, 25, or 27 caliber) to drive the fastener into
the material. The gunpowder charges are made
in different power or load levels to achieve the
proper penetration.
POWDER-ACTUATED
FASTENING
TOOLS ARE TO BE USED ONLY BY
TRAINED AND QUALIFIED OPERATORS
AND IN ACCORDANCE WITH THE
OPERATOR’S MANUAL. Certified operators
must take precautions to protect both themselves and others when using powder-actuated
tools:
• Operate the tool as directed by the
manufacturer’s instructions and use it only
for the fastening jobs for which it was designed.
• To prevent injury or death, make sure that
the drive pin cannot penetrate completely
through and exit the material into which it is
being driven.
• To prevent a ricochet hazard, make sure the
recommended shield is in place on the nose
of the tool.
▼ Figure 3-7.
Powder-Actuated Driver
TOGGLE BOLTS
▼ Figure 3-8.
Toggle Bolts
Toggle bolts (Figure 3-8) are used to fasten
lighter equipment into hollow surfaces such as
walls and ceilings. One type consists of a slotted round-head bolt and spring-loaded wings.
When inserted through the item to be fastened,
then through a hole in the wall or ceiling, the
wings spring apart and provide a firm hold on
the inside of the wall or ceiling as the bolt is
tightened. Note that the hole drilled in the wall
or ceiling should be just large enough for the
compressed wing-head to pass through. Once
the toggle bolt is installed, be careful not to completely unscrew the bolt because the wings will
fall off, making the fastener useless. Another
popular type of toggle bolt used for heavy-duty
fastening in drywall is self drilling with a rotating clamp that flips out of the body and engages
the wall as the bolt is screwed in.
➧ WARNING
STUD
EYE COUPLING
DRIVE PINS
PRE-MOUNTED
CONDUIT CLAMP
SELF-DRILLING DRYWALL TOGGLE BOLT
1
2
3
▼ Figure 3-9.
Common Masonry and Hollow-Wall Anchors
MASONRY AND HOLLOWWALL ANCHORS
Anchors are devices used to give fasteners a
firm grip in a variety of materials where the fasteners by themselves would otherwise have a
tendency to pull out. Anchors can be divided
into two broad categories: those used in solid
masonry and those used in hollow walls and
ceilings made from masonry and other materials. Figure 3-9 shows some common types of
masonry and hollow-wall anchors. Installation
instructions for anchors are normally given on
the anchor box.
WEDGE SLEEVE
STUD
DOUBLE
NAIL MACHINE
EXPANSION ANCHOR SCREW
MASONRY ANCHORS
PLASTIC
TOGGLE
HOLLOW-WALL
AUGER
HOLLOW-WALL ANCHORS
INSTALLING FASTENERS AND ANCHORS 3
Table of Contents
Map
References
Section Topics
SELF-DRILLING, SNAP-OFF
ANCHORS
Some expandable anchors made for use in
masonry are self drilling. Figure 3-10 is typical
of those in common use. This fastener has a
cutting sleeve that is first used as a drill bit and
later becomes the expandable fastener itself.
A rotary hammer is used to drill the hole in the
concrete using the anchor sleeve as the drill
bit. This is followed by inserting the anchor’s
expander plug into the cutting end of the sleeve.
The anchor sleeve and expander plug are
driven back into the hole with the rotary hammer until the sleeve shear point is flush with
the surface of the concrete. As the fastener is
hammered down, it hits the bottom, where the
tapered expander causes the fastener to expand and lock into the hole. The anchor is then
snapped off at the shear point. The component
to be fastened can then be secured to the anchor using the proper size threaded bolt.
▼ Figure 3-10.
Self-Drilling, Snap-Off Anchor
ROTARY
HAMMER
CHUCK
SHEAR POINT
CUTTING SLEEVE
TAPERED EXPANDER
EPOXY ANCHORING
SYSTEMS
Epoxy resin compounds can also be used to
anchor various fasteners (Figure 3-11). Epoxy
is installed in a drilled and cleaned hole of the
proper diameter and depth. One type of epoxy
system uses a tool similar to a caulking gun to
fill the drilled hole about 1/2 full. The selected
fastener is pushed into the hole with a slow
twisting motion to make sure that the epoxy fills
all voids and crevices, then is set to the required
plumb (or level) position. After the epoxy is hardened, the fastener nut can be tightened to
secure the component or fixture in place.
▼ Figure 3-11.
Fastener Anchored in Epoxy
ANCHOR
BOLT
CONCRETE
FOUNDATION
SURFACE
FLAT WASHER
CORE
FILLED
HOLE
EPOXY
GUIDELINES FOR DRILLING
ANCHOR HOLES IN
MASONRY
When installing anchors and/or anchor bolts in
concrete, make sure the area where the equipment is to be located is smooth so that it will
have a solid and level footing.
Before starting, carefully inspect the rotary
hammer or hammer drill and the drill bits
(Figure 3-12) to make sure they are the correct
type and in good condition. Also, set the drill or
hammer tool depth gauge to the correct depth.
DRILLING IN CONCRETE GENERATES
NOISE, DUST, AND POSSIBLE FLYING OBJECTS. ALWAYS WEAR THE PROPER
PROTECTIVE EQUIPMENT. The key to using
masonry drill bits is not to force them into the
material. Use a little pressure and let the drill
do the work. For large holes, start with a smaller
bit, then change to a larger bit.
▼ Figure 3-12.
Masonry and Percussion Drill Bits
CUTTING EDGE
PERCUSSION BIT
➧ WARNING
CUTTING EDGE
MASONRY BIT
INSTALLING FASTENERS AND ANCHORS 3
Table of Contents
Map
Section Topics
MACHINE BOLTS, SCREWS,
AND RELATED HARDWARE
References
▼ Figure 3-13.
Machine Bolts, Screws, Cap Screws, and
Stud Bolts
Various threaded machine bolts, screws, and
studs (Figure 3-13) are used to assemble and
hold together HVAC equipment.
Machine Bolts, Screws, and Studs
Machine bolts are used for general assembly
of parts that do not require close tolerances.
When selecting a machine bolt, pick one that
is long enough so that at least two or three of
the bolt’s threads protrude through the outside
of the nut when assembled. Normally, a machine bolt is used with two or more washers
and a nut. It is tightened and released by turning the nut. Cap screws, stud bolts, and
machine screws are used for specialized fastening needs.
Thread Designations
Machine bolt, screw, and stud threads are made
to different standards that determine their thread
series and classes. The most common is the
unified or American National Standard. There
are three series of threads defined by this standard based on the number of threads per inch
for a certain diameter fastener (Figure 3-14).
Metric screw threads based on the American
National Standard are also in common use.
▼ Figure 3-14.
Machine Bolt and Screw Unified National Series
Thread Designations
3/4 - 10 - UNC - 2A - LH
NOMINAL SIZE (DIAMETER)
NO. OF THREADS PER INCH
THREAD SERIES SYMBOL*
THREAD CLASS SYMBOL**
LEFT-HAND THREAD (NO DESIGNATION IF R.H. THREAD)
* UNC = UNIFIED NATIONAL COARSE THREAD
UNF = UNIFIED NATIONAL FINE THREAD
UNEF = UNIFIED NATIONAL EXTRA FINE THREAD
** 1A, 2A, 3A = CLASS OF FIT FOR EXTERNAL THREADS
(BOLTS, SCREWS)
1B, 2B, 3B, = CLASS OF FIT FOR INTERNAL THREADS
(NUT)
INSTALLING FASTENERS AND ANCHORS 3
Table of Contents
Map
References
Section Topics
Fastener Grade Designations
The strength and quality of bolts can be determined by grade markings placed on the head
of the bolt. These markings are standardized
by the Society of Automotive Engineers (SAE)
and the American Society for Testing of Materials (ASTM). Good practice is to always use
bolts that have grade markings, since bolts that
do not may be inferior. Figure 3-15 shows the
grade markings for commonly specified steel
bolts.
▼ Figure 3-15.
Markings for Common Grades of Steel Bolts
GRADE
SAE 1 OR 2 SAE 5
SAE 7
SAE 8
GRADE MARK
INCREASED STRENGTH
Flat and Lock Washers
Flat washers (Figure 3-16) provide an enlarged
surface used to distribute pressure under the
bolt head and the nut. Lock washers are used
to keep bolts or nuts from working loose. They
are placed between the flat washers and the
bolts or nuts. Some common types of lock
washers include:
• Split ring – Common type used with bolts and
cap screws.
• External – Provides the greatest resistance.
• Internal – Used on small screws.
• Internal-external – Used for oversized mounting holes.
• Countersunk – Used with flat or oval-head
screws.
▼ Figure 3-16.
Flat and Lock Washers
EXTERNAL
INTERNAL
COUNTERSUNK
INTERNAL-EXTERNAL
SPLIT RING
FLAT
Nuts
Nuts used with most threaded fasteners have
hex or square shapes and are normally used
with bolts having the same head shape.
Figure 3-17 shows different types of nuts. Some
special purpose nuts are:
• Acorn nut – Used when there are exposed,
sharp threads on the fastener or when appearance is important.
• Castellated, or castle, and slotted nuts – After the nut is tightened, a cotter pin is fitted in
one set of the nut slots and through a hole in
the bolt to keep the nut from loosening.
• Self-locking nut – Has a nylon insert or is
slightly deformed so it cannot work loose.
• Wing nut – Allows for frequent loosening and
tightening of a fastener.
▼ Figure 3-17.
Nuts
HEX
THICK NUT
HEX
SLOTTED NUT
MACHINE SCREW NUTS
HEX
CASTLE NUT
CAP
SELF-LOCKING WING NUT
(ACORN) NUT
Set Screws
Set screws (Figure 3-18) are commonly used
to fasten pulleys and fan blades on shafts and
to hold collars in place. Set screws are identified by their head and point styles.
▼ Figure 3-18.
Set Screws
HEX SOCKET SLOTTED
HEAD
HEAD
QUICK NOTE
FLUTED
HEAD
SQUARE
HEAD
Once a self-locking nut has been
used and removed, discard it and
replace it with a new one.
FLAT
OVAL
CONE
DOG
POINT
CUP
HALF
DOG
POINT
INSTALLING FASTENERS AND ANCHORS 3
Table of Contents
Map
References
Section Topics
INSTALLING THREADED
FASTENERS
To get the required clamping force and to avoid damage to parts, machine bolts, screws, and
other threaded fasteners must be tightened correctly. Select the proper type and grade of fastener, then tighten (torque) it to specifications using a torque wrench.
Torque Wrenches
The torque wrench (Figure 3-19) is a combination wrench and measuring tool which
measures the resistance to turning or twisting.
The torque wrench consists of a handle and an
attached indicator calibrated to measure torque
in either foot-pounds or inch-pounds. It is normally attached to the nut or bolt to be fastened
using the correct size socket.
▼ Figure 3-19.
Torque Wrenches
Tightening Sequence and
Torquing Guidelines
BEAM-TYPE
0
0
0
0
50
50
0
50
50
0
50
50
0
0
50
0
0
50
50
50
0
0
50
50
0
0
50
0
50
50
0
50
Before assembling equipment, be sure that all
the threaded fasteners are clean and undamaged in order to get accurate torque settings.
Use a torque wrench that will provide the
needed capacity and accuracy. This is generally one that will read near mid-scale when the
specified torque is applied. Using a wrench with
too large a torquing capacity normally makes it
difficult to get an accurate reading because the
scale divisions are too coarse. Using one with
too small a capacity will not allow for the extra
capacity needed in the event the bolt seizes or
encounters run-down resistance.
When installing fasteners in or on equipment, always refer to the equipment
manufacturer’s installation and service instructions for the recommended torque
values. When no specifications are given, the
guideline values shown in Figure 3-20 can be
used for the common graded steel bolts shown.
When installing bolts or screws on flanges
or flat surfaces, they must be tightened in the
proper sequence or pattern to prevent warping
or damage. When installing fasteners in
flanges and other surfaces in or on equipment, always refer to the equipment
manufacturer’s installation and service instructions for the recommended tightening
pattern.
MICROMETERTYPE
➧ CAUTION
➧ CAUTION
▼ Figure 3-20.
Torque Values for Common Graded Steel
Fasteners
GRADE
SAE 1 OR 2 SAE 5
SAE 7
SAE 8
GRADE MARK
BOLT
THREADS
DIAMETER PER INCH
1/4
5/16
3/8
7/16
1/2
9/16
5/8
3/4
7/8
1
20
18
16
14
13
12
11
10
9
8
* CLEAN, DRY THREADS
FOOT-POUNDS
TORQUE*
5
11
18
28
39
51
63
105
160
235
8
17
31
49
75
110
150
270
395
590
10
19
34
55
85
120
167
280
440
660
12
24
44
70
105
155
210
375
605
910
INSTALLING FASTENERS AND ANCHORS 3
Table of Contents
Map
References
Section Topics
QUICK NOTE
• To convert inch-pounds to foot-pounds, divide the inch-pounds by 12. For example, 72 inchpounds ÷ 12 = 6 foot-pounds.
• To convert foot-pounds to inch-pounds, multiply the foot-pounds by 12. For example, 6 footpounds x 12 = 72 inch-pounds.
• Tables of recommended torque values for use with most types and sizes of fasteners can be
found in any one of several mechanical trade handbooks and/or manuals normally available at
your parts distributor or local bookstore.
• Whenever possible, apply the force to the torque wrench by pulling rather than pushing. This
reduces the chance of injury to the fingers or knuckles should some part fail unexpectedly.
• Check the calibration of a torque wrench regularly to maintain its accuracy.
KEYS
Keys (Figure 3-21) are metal parts used to prevent a gear or pulley from rotating on a shaft.
Half of the key fits into a keyseat on the shaft,
while the other half fits into a keyway in the hub
of a gear or pulley.
▼ Figure 3-21.
Common Shaft Keys
KEYWAY
SQUARE
BLIND (POP) RIVET
INSTALLATION
Blind (pop) rivets are used to permanently join
sheet metal and/or other materials
(Figure 3-22). Blind rivets are installed from one
side using a special riveting tool. The rivets are
made of steel, aluminum, and copper and come
in various lengths, diameters, and head styles.
When using blind rivets, select those made of
the same material as the metal being joined to
prevent galvanic corrosion.
The general procedure for installing a blind
rivet is outlined below.
1. Place the rivet’s shaft or mandrel fully into
the riveting tool’s nosepiece.
2. Insert the rivet body into the correctly sized
drilled hole until its flange is flush against the
surface of the metal.
3. Squeeze the rivet tool’s handles until the rivet
mandrel breaks off at the flange.
4. Remove the broken mandrel from the rivet
tool.
GIB HEAD
KEYSEAT
PRATT &
WHITNEY
WOODRUFF
▼ Figure 3-22.
Blind (Pop) Riveting Tool and Rivets
MANDREL
RIGGING, HOISTING, AND MOVING 4
▼RIGGING, HOISTING, AND MOVING
SECTION 4
INTRODUCTION
Installation jobs require the movement of heavy equipment, materials, and tools from one place
to another. This task, called rigging, involves the use of special moving devices such as hand
trucks, dollies, hoists, cranes, and related accessories. Rigging is a skilled profession and should
always be performed by qualified riggers. However, the HVAC technician often is called on to
assist riggers in their job. The focus of this section is on the basic knowledge and skills needed by
the HVAC technician to assist the rigger. It is important that the technician recognize common
items of rigging equipment, use correct rigging methods, and follow correct procedures to prevent personal injury.
RIGGING MENU
Equipment / Material Moving Devices
Hand Trucks, Dollies, and Pry Bars
Ratchet Pullers
Rigging Equipment and Attachment Hardware
Wire and Fiber Ropes
Lifting Slings
General Rigging Procedures
Size, Weight, and Center of Gravity Loads
Inspecting Rigging Equipment
Rigging and Moving Loads
RIGGING, HOISTING, AND MOVING 4
Table of Contents
Map
References
Section Topics
EQUIPMENT/MATERIAL
MOVING DEVICES
▼ Figure 4-1.
Hand Tools and Equipment
Many special tools are made to help move
heavy objects. They save time and manpower,
and help prevent lifting injuries. Hand trucks
(Figure 4-1), portable dollies, pry bars, etc. are
commonly used to manually move and position heavy equipment and materials on the job
site.
BELT
Hand Trucks, Dollies, and Pry Bars
Hand trucks are used to move loads up to several hundred pounds. Good hand trucks are
equipped with skid bars or glide plates to make
their use on stairs and curbs easier. They also
may have a load remover that allows foot pressure to remove the hand truck from under the
load. Hand trucks built for moving appliances
are equipped with rachet take-up belts that secure the appliance, preventing it from slipping
or shifting. Some have continuous belted stair
crawlers to make climbing and descending
stairs easier.
Dollies can be used to move bulky loads over
floors and other flat, solid surfaces. When
equipment has a flat bottom, several short
lengths of pipe may also be used to move the
equipment across a flat, solid surface (Figure
4-2). Enough pipe sections should be available
so that one is always free to be placed in front
of the load as it is moved along.
Pry bars provide the leverage needed for
moving heavy equipment on or off dollies.
HAND TRUCK
APPLIANCE TRUCK
DOLLY
PRY BARS
▼ Figure 4-2.
Pipe Sections Used to Move a Heavy Load
Ratchet Pullers
Ratchet pullers (Figure 4-3), often called comealongs, are typically used to position equipment.
They are available in a wide range of load capacities. Some have a chain for pulling; others
use wire ropes (cables). Some cable models
have two lines and load hooks that can be used
for double-line rigging. RATCHET PULLERS
MUST NEVER BE USED TO LIFT OR SUPPORT ANY LOADS SUSPENDED OVER
PEOPLE.
➧ WARNING
▼ Figure 4-3.
Ratchet Cable Puller
SUSPENSION HOOK
RATCHET
SAFETY LATCH
QUICK NOTE
LOAD HOOK
Plywood or similar paneling can be used to help move heavy equipment across rough or soft surfaces,
such as a carpeted floor. Use two pieces, one under the load and one placed in front of the load as it is
moved along.
RIGGING, HOISTING, AND MOVING 4
Table of Contents
Map
References
Section Topics
RIGGING EQUIPMENT AND ATTACHMENT
HARDWARE
Rigging equipment and attachment hardware are used to lift HVAC equipment. The truck-mounted
crane is commonly used. Wire and fiber ropes, slings, and other rigging hardware are used attach
the load to the crane.
Wire and Fiber Ropes
Wire rope or cable is strong and durable. It consists of wires, strands, and a central core
(Figure 4-4). Wire ropes are commonly made
from galvanized steel.
Wire ropes use shackles, hooks, and other
fasteners that allow for quick attachment to the
load and crane. Figure 4-5 shows some common fittings and fasteners. The thimbles shown
are grooved metal rings that fit around or inside a wire rope loop to protect it from wear
and over-bending.
U-bolt clips (Figure 4-6) are commonly used
for fastening the end of a wire rope when forming a loop eye. A thimble should be used in the
loop eye to prevent kinking. The diameter of
the wire rope determines how many clips must
be used and the spacing between them.
(See Table 4-1.)
Fiber ropes are used for lifting lighter loads
and as safety tag lines. For a given size, synthetic ropes are normally stronger and lighter
in weight than ropes made of natural fibers.
Only manila ropes made of No. 1 manila are
acceptable for use in rigging. These are normally identified by rope manufacturers with
some kind of marking, such as colored inlaid
fibers. Manila ropes not marked as No. 1
grade should not be used, because they are
made from an inferior fiber.
Ropes are generally rated by tensile or breaking strength and/or safe working load. Safe
working load is the maximum load a rope can
safely carry. Do not confuse the terms tensile
strength and safe working load, because the
safe working load is only a small percentage of
the tensile strength. For example, a 3/8-inch
diameter nylon rope may have a tensile strength
of 3,700 pounds and a safe working load of only
308 pounds. Always be sure to refer to the
manufacturer’s data when selecting ropes for
a lifting job.
When a crane starts to pick up a load, the
attached ropes are subjected to sudden and
extreme stress or shock loads called dynamic
loading. The more rapid the acceleration when
lifting the load, the greater the dynamic load. If
the dynamic loading is large for a particular lifting job, make sure to select a rope that has an
adequate safe working load capacity to compensate for the dynamic loading. When lifting
a load that is close in weight to a rope’s safe
working load capacity, make sure to accelerate the load slowly when lifting it.
▼ Figure 4-4.
Wire Rope
CORE
WIRE
CENTER
STRAND
▼ Figure 4-5.
Common Wire Rope Fittings and Fasteners
SLIP-THRU
THIMBLE
CLOSED
➧ CAUTION SOCKET
WIRE ROPE
THIMBLE
SHACKLE
OPEN
SOCKET
▼ Figure 4-6.
Correct Use of U-Bolts when Forming a Loop in
Wire Rope
▼ Table 4-1.
Determining the Number of U-Bolt Clips Required
Wire Rope Number of
Size
U-Bolts
Spacing
3/8
2
4
7/16
2
4-1/2
1/2
3
5
5/8
3
5-3/4
3/4
4
6-1/4
7/8
4
8
1
4
8-3/4
QUICK NOTE
The effects of dynamic loading are not included in a rope manufacturer’s stated value for safe
working load. Make sure to select a rope that has an adequate safe working load to compensate for
any dynamic loading.
RIGGING, HOISTING, AND MOVING 4
References
Section Topics
▼ Figure 4-7.
Eye-and-Eye Lifting Slings
STRAIGHT LIFT
100%
CHOKER HITCH
75%
60°
BASKET HITCH
200%
45°
BASKET HITCH
100%
30°
BASKET HITCH
140%
BASKET HITCH
175%
APPROXIMATE LOAD CAPACITIES SHOWN IN PERCENT
RELATES TO THE SLING'S "STRAIGHT LIFT" RATED
LOAD CAPACITY.
▼ Figure 4-8.
Bridle Slings
THREE-LEG
TWO-LEG
SPREADER
BARS
DOUBLE LOOP BRIDLE SLING
60°
90°
s
lb
7
45°
lbs
1,000 LBS
70
bs
7l
1,000 LBS
57
60°
7
Lifting slings are used to attach a load to a
crane’s hook. They can be made of wire rope,
chain, or synthetic materials, and in many
general and specialized forms. Eye-and-eye
wire rope and synthetic slings are versatile
slings that can be used in vertical, choker, and
basket hitch arrangements (Figure 4-7). When
used as a choker or basket hitch, care must be
taken to balance the load so that it rides safely.
Sling manufacturers mark their slings with a
tag that identifies the sling size, type, and safe
load capacity. For example, an eye-and-eye
sling rated at a capacity of 4,000 pounds will
lift 4,000 pounds when used as a vertical hitch.
When used as a choker or basket hitch, the
sling’s capacity is different. Figure 4-7 shows
the approximate load capacities in percent related to a sling’s “vertical hitch or straight lift”
rated load capacity. For example, a sling rated
at 4,000 pounds has a load capacity of about
3,000 pounds when used as a choker hitch.
When used as a basket hitch connected to a
single hook at a vertical angle of 30°, its load
capacity is about 7,000 pounds.
Bridle slings (Figure 4-8) are multi-legged
slings equipped with a loop or ring that attaches
to a crane hook. The ends of the legs can be
equipped with a variety of fasteners. Bridle
slings are made in three basic patterns: the twoleg, three-leg, and four-leg or double loop. The
tension, and therefore the load, on each leg of
a bridle sling increases as the angle between
the legs is increased. For example, the tension
and load are higher on the legs of a bridle sling
when the legs are positioned at an angle of 30°
relative to the horizontal (120° angle between
the legs) than when the legs are at an angle of
60° relative to the horizontal (60° angle between
the legs). This load capacity difference must
be taken into consideration when selecting a
bridle sling for a particular lifting job.
70
Lifting Slings
500 lbs
57
7l
bs
Map
500 lbs
Table of Contents
1,000 LBS
120°
1
lbs ,000
00
lbs
1,0 30°
1,000 LBS
WHEN THE ANGLE BETWEEN THE LEGS INCREASES, THE
TENSION ON EACH LEG INCREASES.
RIGGING, HOISTING, AND MOVING 4
Table of Contents
Map
Section Topics
References
GENERAL RIGGING
PROCEDURES
Size, Weight, and Center of Gravity of Loads
The correct size and weight of loads must be known in order to select the right type of rigging
equipment. For the size and weight of HVAC equipment, always refer to the equipment
manufacturer’s installation instructions. Make sure to include any additional weight added by
optional equipment. For example, a rooftop unit weighs a certain amount. When equipped with an
optional economizer, the weight increases.
Safety demands reasonable accuracy when
estimating the weight of an object. Professional
riggers are trained to perform this task and
should be the only persons on the jobsite
trusted to do it. If the weight of a load is unknown and no accurate estimate can be made,
contact the equipment supplier to find out the
weight. NEVER ATTEMPT TO LIFT A LOAD
➧ WARNING
WITHOUT KNOWING ITS WEIGHT.
The center of gravity of an object is the exact point at which the object is balanced in all
directions. If a load is unbalanced, it may twist,
turn, or fall, causing possible injury or damage
to the equipment.
To make a level lift, sling(s) of the proper
length to balance the load must be used and
the crane’s hook must be directly above the
load’s center of gravity (Figure 4-9). HVAC ▼ Figure 4-9.
equipment normally comes with lifting lugs, eye
Crane’s Hook Must be Centered Directly Over the
Load’s Center of Gravity
bolts, or holes in the base rails located in the
proper places to establish the center of gravity.
For HVAC and other equipment, always refer
CENTER OF
to labels attached to the equipment or the equipGRAVITY
ment manufacturer’s installation instructions for
data on the use of such lifting points. Skill in
estimating the center of gravity for odd-shaped
and/or unbalanced loads comes with experience. When no specific rigging data is given,
estimating the center of gravity for an unbalanced load should be performed by a
professional rigger.
RIGGING, HOISTING, AND MOVING 4
Table of Contents
Map
Section Topics
References
Inspecting Rigging Equipment
To ensure safe and proper operation, rigging equipment should always be inspected before use,
and at regular intervals during periods of prolonged use. EQUIPMENT THAT IS WORN OR
DAMAGED COULD RESULT IN DEATH OR INJURY AND/OR DAMAGE TO THE EQUIPMENT.
IF IN DOUBT ABOUT THE CONDITION OF A PIECE OF EQUIPMENT, DO NOT USE IT. Guidelines for inspecting rigging equipment are given in Table 4-2.
▼ Table 4-2.
Guidelines for Inspecting Rigging Equipment
Equipment
Wire rope and slings
Inspect for the Following Defects
Broken wires in rope lay or strands.
Abrasion that has caused a significant reduction (about 1/3) in the original
diameter of the rope.
Deterioration from corrosion.
Shape is distorted as a result of kinking or crushing.
Signs of heat damage.
Unraveling of a splice.
Inner core is showing or protruding.
Hooks, shackles, and
sockets
Bent, broken, twisted, or otherwise damaged or loose shackle pins.
Broken or missing cotter or clevis pin.
Damaged or missing hook safety latch.
Synthetic slings
Colored inner yarn visible.
Cuts, tears, or broken fibers.
Worn or damaged end fittings.
Signs of heat or chemical damage.
Equipment to be rigged
Damaged pad eyes.
Eyebolts not threaded all the way in.
Loose parts.
RIGGING, HOISTING, AND MOVING 4
Table of Contents
Map
References
Section Topics
Rigging and Moving Loads
Safely lifting loads requires making decisions
regarding the load to be moved and the lifting
and rigging equipment that will be used. These
decisions should be made by a professional rigger.
Some guidelines and precautions to be followed when assisting a rigger in preparation
for and during the lift are:
• Never attempt rigging or hoisting in bad
weather.
• Rigging should always be performed under
the supervision of a qualified rigger.
• All loose materials must be removed from
the load before it is moved.
• Whenever two or more rope loops need to
be placed over a hook, use a shackle (shown
earlier in Figure 4-5).
• Secure all unused sling legs (Figure 4-10).
• Pad the corners of a sharp load to prevent
cutting of the slings or rope. Do not bend wire
ropes near splices or attached fittings
(Figure 4-11).
• Use tag lines on all lifts to control the load
(Figure 4-12). Do not hold onto the load with
your hands. Keep hands, arms, feet, etc.
away from and out of pinch points. Do not
wrap tag lines around hands, waist, or any
other part of your body.
• Before making a lift, make sure the rope or
sling(s) have no kinks.
• While making a lift, have one authorized person use a radio or other device to give
directions and maintain contact with the
crane operator.
• When lifting loads with slings, lift slowly and
uniformly.
• Never walk under the load during the lift.
• Never unhook a load until it is safely landed
and properly secured.
QUICK NOTE
Inspect rigging equipment before using!
• Wire and fiber ropes and slings
• Hooks, shackles, and sockets
• Equipment or material to be rigged
▼ Figure 4-10.
Secure all Unused Sling Legs
UNUSED
SLING LEGS
▼ Figure 4-11.
Do Not Bend Wire Ropes Near Splices or Fittings
SPLICE
SPLICE
▼ Figure 4-12.
Use Tag Line to Control the Load
PIPING SYSTEMS 5
▼ PIPING SYSTEMSS
SECTION 5
INTRODUCTION
Installation jobs can require an HVAC technician to install refrigerant, gas, and condensate piping
systems. This commonly involves installing copper pipe/tubing to carry refrigerant, steel or wrought
iron pipe to carry natural gas in heating systems, and plastic pipe to vent combustion gases or
drain condensate water in both cooling and heating systems. This section focuses on the general
procedures for handling, cutting, and joining the various piping materials commonly used in HVAC
systems. Specific information about installing different types of piping systems is provided in
Sections 8 through 10.
PIPING MENU
Refrigerant Copper Piping / Tubing and Fittings
Soft ACR Copper Tubing
Line Sets
Hard ACR Copper Piping
Handling ACR Copper Tubing
Cutting and Deburring Copper Tubing
Bending Soft Copper Tubing
Flaring and Swaging Soft Copper Tubing
Soldering and Brazing Copper Tubing
Gas Piping and Fittings
Black Iron / Galvanized Steel Pipe and Fittings
Cutting and Reaming Steel Pipe
Threading Steel Pipe
Assembling Steel Pipe and Fittings
Plastic Piping and Fittings
Pipe Types and Sizes
Cutting and Joining
Pipe Hangers and Supports
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
REFRIGERANT COPPER PIPING/TUBING AND FITTINGS
Air conditioning and refrigeration (ACR) copper pipe and fittings are manufactured specifically for
use in refrigeration systems. ACR pipe is thoroughly cleaned, dried, capped, and sometimes
charged with nitrogen to help prevent contamination of the refrigeration system. Never use copper piping made for general plumbing use in a refrigeration system because it does not
conform to the higher cleanliness standards required in refrigeration systems. Another
important difference is that the size of ACR pipe is expressed by its outside diameter (O.D.), while
copper pipe used for general plumbing is expressed in terms of its inside diameter (I.D.).
ACR copper tubing is made in both soft and hard forms. Both are classified by their wall thickness. Type L (medium wall) is used under normal conditions; Type K (heavy wall) is used where
severe corrosion may occur. The O.D. of both types is the same. Refrigerant line sizing charts
normally given in manufacturer’s equipment installation literature are based on the use of Type L
piping. Both soft and hard copper pipe may be used in the same system.
Soft ACR Copper Tubing
Soft ACR copper tubing made in sizes from 1/8-inch to 7/8-inch O.D. and supplied in 50-foot rolls
is typically used in HVAC installation work. Because of its length, soft copper tubing needs fewer
connections, reducing the chance of leaks. It is easily bent or shaped, but must be held in place
by clamps or other hardware as it cannot support its own weight. Joints and connections can be
made by soldering, brazing, or using flare fittings.
Line Sets
Manufacturers of HVAC equipment make soft
ACR refrigerant line tubing kits, called line sets
(Figure 5-1). Line sets come in many lengths
and tube sizes and may have fittings on each
end that allow for quicker field installation. They
may be pre-charged with refrigerant and sealed
at both ends. The suction tubing is usually insulated. The installation of line sets is covered
in detail in Section 9.
▼ Figure 5-1.
Soft Copper Line Set
INSULATED SUCTION LINE
LIQUID LINE
Hard ACR Copper Piping
Hard copper ACR pipe comes in 20-foot lengths
and similar sizes to soft copper tubing. It is designed to be used with fittings such as elbows
and tees (Figure 5-2) to make necessary bends
or changes in direction. Joints and connections
are made by soldering or brazing.
PROTECTIVE
CAPS
▼ Figure 5-2.
Hard Copper Pipe and Fittings
Handling ACR Copper Tubing
ACR tubing and fittings must be kept clean and
dry to prevent system contamination. Piping
and fittings should remain capped and stored
in a clean place until just before installation.
When cutting lengths of pipe, cut only what is
needed, then immediately recap any unused
lengths. When unrolling soft copper tubing,
good practice is to place the roll upright on a
flat surface and unroll the tubing. Do not lay
the coil flat and uncoil the tubing from the side
of the roll. Also, do not bend or straighten the
tubing more than necessary, because this will
cause it to harden.
RIGID COPPER PIPE
UNION
90° ELBOW
(SHORT RADIUS)
TEE
90° ELBOW
(LONG RADIUS)
45° ELBOW
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
Cutting and Deburring Copper
Tubing
Both soft and hard copper tubing should be cut
using the proper size tubing cutter
(Figure 5-3). Do not confuse a tubing cutter with
a pipe cutter. Tubing cutters are designed for
clean, square cuts in soft, thin-wall materials
such as copper. To use the cutter, place it over
the tubing and tighten the adjusting knob until
the cutting wheel is aligned with and touches
the tubing at the point where it is to be cut.
Rotate the cutter around the tubing, keeping a
moderate pressure applied to the tubing by
tightening the adjusting knob slightly on each
rotation until the tubing is cut.
Deburr the tube by inserting the cutting tool
deburring blade into the cut end and gently
twisting it until the inside edge of the tube is
smooth or use a dedicated deburring tool. Keep
the end of the tubing pointed downward so that
the metal chips fall out of (not into) the tubing.
▼ Figure 5-3.
Using a Tubing Cutter
ADJUSTING
KNOB
DEBURRING
BLADE
ROTATE
CUTTER
TUBE REAMER/
BURR REMOVER
Bending Soft Copper Tubing
Soft copper tubing can be joined by soldering
or with mechanical fittings. Soldering of copper
tubing is described later in this section. Flare
connections and fittings are the most common
mechanical method used for joining soft copper tubing. A special flaring tool (Figure 5-5) is
used to expand the end of the tubing into the
shape of a 45° cone (flare) that mates with an
equipment connector or flare fitting.
SPRING-TYPE
BENDER
45
90
145
180
Flaring and Swaging Soft Copper
Tubing
▼ Figure 5-4.
Soft Copper Tubing Benders
0
Soft copper tubing 5/8-inch in diameter and less
is flexible enough to bend by hand. Use a
spring-type bender (Figure 5-4) of the proper
size slipped over the tubing to prevent kinking
or flattening. Kinks restrict the flow of refrigerant through the tube. A mechanical tube bender
is used for larger-diameter tubing and when an
accurate bend is required. It can be used to
get smooth bends at any angle up to 180°.
These benders normally have a clip to hold the
tubing while bending, and a calibrated degree
scale.
MECHANICAL BENDER
▼ Figure 5-5.
Flaring Tool and Flared Connection
YOKE AND CONE
FLARING BAR
FLARE NUT
FLARE ON TUBING
FLARE FITTING
QUICK NOTE
Always use a drop of oil on the flaring
tool cone and feed screw to prevent
binding during the flaring operation.
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
Flared connections must be made correctly or they will leak. For best results, always follow the
flaring tool manufacturer’s instructions. A general procedure is outlined below:
1. Use a tubing cutter to cut and deburr the tubing.
2. Slide a flare fitting nut over the tubing with its threads facing the end of the tubing being flared.
3. Place the tubing in the correct size die in the tool flaring bar. The tube must extend the correct
distance above the bar (typically 1/3 the total height of the flare). If it extends too far, the end of
the tube may split; if it is not far enough, the flare will be too small to seal tightly.
4. Place the tool yoke with attached tapered cone on the flaring bar with the cone positioned over
the end of the tubing.
5. Make sure the tubing is clamped in the flaring bar, then screw the cone down into the tubing
until the flare is completed.
6. Remove the tubing from the block and inspect the flare to make sure there are no defects.
Soft copper tubing of the same diameter can
also be joined by making a swaged connection. This type of joint is made using a swaging
tool (Figure 5-6) to expand the end of one pipe ▼ Figure 5-6.
Making a Swaged Joint
so that a same-diameter pipe can fit inside. Either a punch-type or lever (expander)-type tool
can be used to make swaged joints. Good practice is to make the depth of the swaged joint
equal to the outside diameter of the tubing.
Once the swaged joint is formed, the joint is
either soldered or brazed.
Soldering and Brazing Copper
Tubing
Soldering and brazing are two methods used
to join soft and hard copper tubing. As a rule,
soldered joints provide good sealing but are not
as strong as brazed joints. Soldered joints typically are used to join copper water and drain
pipes where temperatures do not exceed 250°
F. Brazed joints provide the mechanically stronger joint needed to handle the higher pressures
in refrigerant piping systems. Detailed procedures for performing soldering and brazing are
described later in this section. Figure 5-7 briefly
shows the steps in the process.
The soldering and brazing processes use
heat to melt solder or a brazing rod, respectively, to join the tubing. When heated, the alloy
melts and is distributed between the surfaces
being joined in a kind of soaking or spreading
action, called capillary action. The difference
between soldering and brazing is the temperature needed to melt the alloy (Figure 5-8).
Soldering is done at temperatures ranging between 400° F and 800 °F, with the heat
commonly supplied by a propane torch. Brazing is done at temperatures above 800° F,
usually with an oxyacetylene torch.
1/2-IN. TUBING
1/2
IN.
▼ Figure 5-7.
Steps of the Soldering or Brazing Process
1. CUT AND SIZE PARTS TO
BE JOINED
2. CLEAN PIPE END
3. FLUX
4. HEAT
5. APPLY FILLER METAL (ALLOY)
6. QUENCH & CLEAN JOINT WITH WET RAG
7. INSPECT JOINT
▼ Figure 5-8.
Temperature Ranges for Soldering and Brazing
BRAZING
800° F – 1500° F
400° F – 800° F
SOLDERING
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
ad-Free S
Paste Flux
er
old
Le
Soldering/Brazing Alloys and Fluxes – Al▼ Figure 5-9.
Soldering Alloys
loys used to make soldered joints are different
from those used to make brazed joints
(Figure 5-9). Alloys used for soldering in most
HVAC work contain tin and varying amounts of
either antimony or silver. For joining copper, an
alloy made up of 95% tin and 5% antimony
Lead-Free Solder
Paste Flux
should always be used. Since this solder melts
at about 465° F, an air-propane or air-acetyFLOWPOINT (°F)
TYPE
lene torch can be used. Lead-free silver-bearing
SILVER-BEARING
soft solders are also available. They can be
400 - 550
SOFT SOLDER
used to join the same or dissimilar metals.
95% TIN/5% ANTIMONY
Two types of brazing alloys are commonly
SOFT SOLDER
465
(FOR JOINING
used in HVAC work: a silver-bearing alloy and
COPPER-TO-COPPER
a copper-phosphorus alloy (Figure 5-10). SilONLY)
ver-bearing alloys, commonly called silver
solder, can contain from 30 to 60 percent silver. Silver solder alloys are suitable for joining
▼ Figure 5-10.
the same or dissimilar metals such as copper
Brazing Alloys
to copper, copper to steel, or copper to brass.
They require the use of the proper flux. CopBRAZING
RODS
per-phosphorus alloys, commonly called
FLUX
phosco, sil-fos, or phoson are used only to join
copper to copper. Copper-phosphorus alloys
are self-fluxing so they do not require the use
of flux. Both types of alloys require high temTYPE
FLOWPOINT (°F)
peratures to flow and typically require heating
SILVER-BEARING
1200 - 1300
with an oxyacetylene torch.
BRAZING ALLOYS
Flux is a chemical substance that dissolves
PHOSPHORUS-BEARING
and removes traces of oxides from the surfaces
BRAZING ALLOYS
1500
(FOR JOINING SIMILAR,
being joined, protects the surfaces from re-oxiNON-FERROUS METALS
dation during heating, and helps the melted
ONLY)
alloy to flow into the joint. Flux does not clean
the metal. It keeps the metal clean once it has
been cleaned by other means. Some fluxes
provide a relative temperature indication of the
metal being heated by changing color or texture with increases in temperature.
For best results when soldering or brazing, always use the flux recommended by the manufacturer of the solder or brazing alloy being used, or its equivalent. Do not interchange fluxes used
for soldering and brazing copper joints because they are different in composition.
Air-Acetylene and Oxyacetylene Torches – Soldering and brazing involves the use of torches
and pressurized gases. General safety precautions pertaining to torches and pressurized gases
are covered in Section 2. General procedures for setting up and operating air-acetylene and
oxyacetylene torches are given here. The procedures for using these torches to solder or braze
are given later in this section.
Acetylene Torch Set-Up – The air-acetylene
torch (Figure 5-11) normally consists of a B or
MC tank of acetylene gas, regulator, hose, torch
handle, and a variety of torch tips. The air-acetylene torch is set up and ignited for use as
follows:
1. Prior to connecting the regulator to the tank,
stand to one side and “crack” open the tank
valve slightly. Then close it. This will blow out
any dirt or debris that has entered the valve.
2. Assemble the hose and torch with the required tip to the regulator, then attach the
regulator to the tank. Make sure that all connections are tight.
3. Adjust the regulator valve to midrange. Stand
to one side of the regulator and slowly open
the tank valve about one-half turn.
▼ Figure 5-11.
Air-Acetylene Equipment
HOSE
REGULATOR
TORCH TIP
TANK
VALVE WRENCH
TORCH HANDLE
TANK OF
ACETYLENE
GAS
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
4. Open the torch handle valve slightly and ignite the gas with a friction (spark) lighter
(Figure 5-12). If using a torch that has a builtin ignitor in the tip, push the button to ignite
the gas. WHEN LIGHTING THE TORCH,
POINT THE TORCH TIP AWAY FROM
YOUR BODY AND ANY FLAMMABLE MATERIAL.
5. Adjust the torch valve to get a sharp inner
flame and a blue outer flame. The torch is
now ready to solder.
6. When the soldering is done, shut off the torch
by first closing the torch valve, then the tank
valve. Bleed off any acetylene in the hose by
opening the torch valve, bleeding the hose,
then closing the torch valve.
▼ Figure 5-12.
Use Friction Lighter to Ignite the Torch
➧ WARNING
FRICTION
LIGHTER
QUICK NOTE
Follow these safety precautions when working with air-acetylene or oxyacetylene equipment:
• Keep a fire extinguisher handy.
• Wear safety glasses and gloves.
• Keep cylinders away from heat, sparks, or open flame.
• Store and transport the cylinders in a cart or in a secured upright position.
• Do not handle acetylene and oxygen cylinders with oily hands or gloves. Do not use any oil or
grease on the tank or regulator threaded fittings. Oil or grease in contact with oxygen may
ignite or explode spontaneously.
• Always stand to one side when adjusting regulators. A defective regulator can blow out, causing
injury or death.
Oxyacetylene Torch Set-Up – The oxyacetylene
torch (Figure 5-13) consists of acetylene gas and
oxygen cylinders (tanks), related regulators,
hoses, torch, and a variety of torch tips. The oxyacetylene torch is set up for use as described
below.
1. Install the oxygen and acetylene regulators
on the related tanks:
a. Prior to connecting each of the regulators,
stand to one side and “crack” open, then
close the tank valve. This will blow out any
dirt or debris that may have entered the
valve.
b. Before attaching the regulators to the
tanks, back off (turn counterclockwise) the
regulator knobs until no resistance is felt
(Figure 5-14). Install the oxygen and
acetylene regulators on the tanks. Note
that the oxygen regulator and tank fittings
have right-hand threads and the acetylene
regulator and tank have left-hand threads.
This prevents you from putting the regulators on the wrong tanks.
2. Install and purge the hoses as follows:
a. Install flashback arresters on the oxygen
and acetylene regulators, then connect
the green hose to the oxygen regulator
and the red hose to the acetylene regulator. Install the torch on the ends of the
hoses and open both torch valves.
b. Purge (clean) the oxygen hose. Open the
oxygen tank valve slowly until a small
amount of pressure registers on the oxygen high pressure gauge, then open the
valve completely.
▼ Figure 5-13.
Oxyacetylene Equipment
OXYGEN CYLINDER
VALVE
ACETYLENE
CYLINDER
VALVE
(HIDDEN)
OXYGEN
REGULATOR
ACETYLENE
REGULATOR
GREEN
HOSE
FLASHBACK
ARRESTERS
TORCH OXYGEN
AND ACETYLENE
VALVES
RED
HOSE
TIP
HOSE CONNECTIONS
AT TORCH
▼ Figure 5-14.
Typical Regulator
REGULATOR
ADJUSTING
KNOB
80
120
2000
2500
1500
3000
150
1000
200
40
40
3500
4000
TURN KNOB CLOCKWISE TO INCREASE PRESSURE;
COUNTERCLOCKWISE TO REDUCE PRESSURE
PIPING SYSTEMS 5
References
Section Topics
➧ WARNING
▼ Figure 5-15.
Never Adjust Acetylene Regulator Above 15 psig
NEVER ADJUST REGULATOR ABOVE
15 PSIG BECAUSE ACETYLENE BECOMES
UNSTABLE AND VOLATILE AT THIS PRESSURE
1200
16
0
100
80
150
15
10
00
200
250
100
300
50
400
00
350
5
24
WORKING PRESSURE
GAUGE
2000
c. Turn the oxygen regulator knob clockwise
until a small amount of pressure shows
on the oxygen working pressure gauge.
Allow this pressure to build up and purge
the oxygen hose and torch. Then turn the
oxygen regulator knob counterclockwise
to decrease the pressure. Close the torch
oxygen valve.
d. Purge the acetylene hose in the same way
as was done for the oxygen hose. NEVER
OPEN THE ACETYLENE TANK VALVE
MORE THAN 1-1/2 TURNS. NEVER ADJUST THE ACETYLENE REGULATOR
ABOVE 15 POUNDS PRESSURE (FIGURE 5-15) BECAUSE ACETYLENE
BECOMES UNSTABLE AT EXCESSIVE
PRESSURES.
3. Check the equipment for leaks as follows:
a. Adjust the acetylene regulator knob for 10
psig on the working pressure gauge. Adjust the oxygen regulator knob for 40 psig
on the working pressure gauge.
b. Close the oxygen and acetylene tank
valves and check for leaks. If the gauges
remain at 10 and 40 psig, there are no
leaks. If one or both readings drop, look
for and repair the leak.
DO NOT USE AN OIL-BASED SOAP
OR OTHER SOLUTION FOR LEAK
TESTING. THE MIXTURE OF OIL AND
OXYGEN CAN CAUSE AN EXPLOSION.
c. Open both torch valves to release the
pressure in the hoses, then close the
valves on the torch.
d. Turn the oxygen and acetylene regulator
knobs counterclockwise to release the
pressure in the regulators. The torch is
now ready to be ignited.
400
Map
50
Table of Contents
2800
REGULATOR
ADJUSTING
KNOB
➧ WARNING
Oxyacetylene Torch Ignition and Adjustment – Ignite and adjust the torch flame as follows:
1. Make sure that the following torch conditions exist:
a. Oxygen and acetylene regulators backed out (counterclockwise).
b. Oxygen and acetylene tank valves closed.
c. Oxygen and acetylene torch valves closed.
2. Adjust the torch oxygen system.
a. Open the torch oxygen valve to purge the regulator and hose.
b. Open the oxygen tank valve slowly to prevent damaging the regulator.
c. Adjust the oxygen regulator clockwise for a pressure of 10 pounds on the gauge. This pressure is more than adequate for air conditioning brazing.
d. Shut off the torch oxygen valve.
3. Adjust the torch acetylene system.
a. Open the torch acetylene valve to purge
the regulator and hose.
b. Open the acetylene tank valve slowly.
Never open this valve more than 1-1/2
➧ CAUTION
turns. Be sure to leave the key on the
acetylene cylinder valve so that the valve
can be closed quickly in an emergency.
c. Adjust the acetylene regulator clockwise
for a pressure of 5 pounds on the gauge.
This pressure is adequate for air condi➧ WARNING
tioning brazing. NEVER ADJUST THE
ACETYLENE REGULATOR ABOVE 15
POUNDS PRESSURE.
d. Shut off the torch acetylene valve.
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
4. Light the oxyacetylene torch.
a. Open the torch acetylene valve only and
use a friction lighter to ignite the gas.
b. Adjust the torch acetylene valve to get a
standing flame about 3/4 inch from the
torch tip.
c. Open the torch oxygen valve and adjust
the flame to get a slight feather edge on
the inner cone, then reduce the oxygen
until the feather edge just disappears
(Figure 5-16). This produces a neutral
flame, which is the ideal flame for brazing. The torch is now ready for brazing.
5. Shut off the torch when finished brazing.
a. On the torch, shut off both the oxygen and
acetylene valves.
b. Completely shut off both the oxygen and
acetylene tank valves and back off both
regulators.
c. On the torch, open both valves to bleed
off the regulators and hoses to zero pressure, then close the valves again.
▼ Figure 5-16.
Reduce the Oxygen Until the Feather Edge Just
Disappears, Resulting in a Neutral Flame
FEATHER
INNER
CONE
NEUTRAL FLAME
INNER
CONE
▼ Figure 5-17.
Learn Soldering and Brazing Skills Under the
Supervision of an Experienced Technician
General Brazing/Soldering Techniques –
Soldering and brazing skills can be learned
through practice under the supervision of an
experienced technician (Figure 5-17). Practice
on scrap tubing. Do not practice on the
customer’s equipment. In this section, the
procedure for brazing is described first, followed
by a description of the differences in the procedure for soldering.
Brazing – To braze, follow the general procedure outlined below. Work in a well ventilated
area. Some fumes generated when brazing
can cause irritation.
1. Measure, cut, and deburr the tubing. When
measuring the tubing, make sure to take
into account the extra length needed to
insert the tubing into a fitting.
2. Use a solvent to thoroughly clean any oil or
grease from the surfaces to be joined. Clean
the metal to a bright finish using sandcloth,
being careful not to remove an excessive
amount of metal (Figure 5-18). Avoid touching the cleaned areas with your fingers
because you may contaminate the clean
metal.
3. Using a clean brush, apply a minimum
amount of the correct flux to the outside of
the tubing ends only (Figure 5-19), then assemble the tubing into the fittings. Be careful
not to get flux into the inside of the tubing. If
using a copper-phosphorus brazing alloy, the
use of flux is not required. Flux can irritate
the skin and eyes. Wash off any flux that
gets on your skin or in your eyes.
▼ Figure 5-18.
Clean the Outside of Tubing and the Inside of
Couplings or Fittings with Sandcloth
DO NOT TOUCH CLEAN JOINTS WITH FINGERS
▼ Figure 5-19.
Apply Flux Properly
FLUX
DO NOT APPLY FLUX WITH FINGERS
- USE CLEAN BRUSH OR SWAB
1/8 – 1/16 IN.
APPLY FLUX
SPARINGLY
TO TUBING
FLUX CARRIED INTO
FITTING BY TUBING
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
4. Support the assembled tubing and fittings to
be joined so they do not come apart when
heat is applied. If brazing near a service
valve or similar component, wrap it with
a wet rag to protect it from heat damage
(Figure 5-20).
5. Set up, ignite, and adjust the flame of the
oxyacetylene torch per the instructions given
earlier in this section.
6. Apply the torch flame to the joint. Do not allow the inner cone of the flame to touch the
metal. Heat the male tube near the joint first.
Make sure to keep the torch moving for uniform heating of the parts and to prevent
overheating any one area.
7. If brazing with a silver alloy and flux, watch
the flux. It will first bubble and turn white and
puffy, then melt into a clear liquid. This is an
indication that the metal is hot enough to melt
and flow the filler alloy.
If brazing using a fluxless copper-phosphorus alloy, the same basic process of heating
the metal is used. However, a slightly higher
temperature is normally required to flow the
alloy since it does not flow as easily as the
lower-temperature silver alloy.
8. When the flux becomes clear, shift the flame
to the fitting or female tubing and touch the
brazing rod to the joint to see if it flows
(Figure 5-21). If the metal is hot enough, the
alloy will flow. Do not heat the alloy rod directly. Move the rod around the
circumference of the joint while still applying
heat, allowing the alloy to be drawn into the
joint by capillary action.
9. After the joint is made, quench it with water
to cool the joint and to wash away any flux
residue. Removal of the flux residue is important because it is slightly corrosive and
can cause eventual failure or leakage at the
joint. Inspect the joint for visual signs of
defects.
▼ Figure 5-20.
Wrap Valves and Fixtures Near Joints with
Wet Rags
▼ Figure 5-21.
When Flux Becomes Clear, the Metal is Hot
Enough to Flow the Silver Alloy
WATCH THE FLUX:
• AT 212 ° F THE WATER BOILS OFF.
• AT 600 ° F THE FLUX BECOMES WHITE AND SLIGHTLY
PUFFY AND STARTS TO WORK.
• AT 800 ° F IT LAYS AGAINST THE SURFACE AND HAS A
MILKY APPEARANCE.
• AT 1100 ° F IT IS COMPLETELY CLEAR AND ACTIVE AND
HAS THE APPEARANCE OF WATER.
Soldering – As stated previously, the techniques for soldering and brazing are similar. The difference is the torch used and how the heat and solder are applied to the joint. Solder a joint as
follows:
1. Measure, cut, deburr, clean, and apply the proper flux to the tubing as previously described for
brazing.
2. Set up, ignite, and adjust the flame of the air-acetylene torch per the instructions given earlier
in this section.
3. Apply the flame to the joint. Hold the torch so that the inner cone of the flame just touches the
metal. Heat the male tube near the joint first, then move to the fitting or female tubing. Make
sure to keep the torch moving for uniform heating of the parts and to prevent overheating any
one area.
4. Remove the flame from the joint, then touch the solder to the joint. If the solder does not melt
on contact with the joint, remove it and continue to heat the joint, then try again. Do not melt
the solder with the flame.
5. When the joint temperature is hot enough to melt the solder, apply the heat to the base of the
fitting to help draw the solder into the joint. Continue to feed solder into the joint until a ring of
solder appears around the joint, then stop.
6. After the joint is made, quench it with water to help cool the joint and to wash away any flux
residue. Inspect the joint for visual signs of defects.
PIPING SYSTEMS 5
Table of Contents
QUICK NOTE
Map
References
Section Topics
BRAZING AND SOLDERING TIPS
• When joining larger tubing, a double-tip torch (Figure 5-22) can supply the needed heat.
• If the filler alloy fails to flow or balls up, it can indicate oxidation of the metal surfaces, or insufficient
heat on the parts to be joined.
• If work starts to oxidize during heating, it indicates the use of too little flux.
• If the alloy does not enter the joint but tends to flow over the outside of either part of the joint, it can
indicate that one part is overheated, one part is underheated, or both. If this happens, stop brazing,
disassemble the joints, and reclean and reflux the parts.
Purging while Brazing/Soldering – When
copper tubing is heated, it reacts with the oxygen in the air to form copper oxide within the
tubing. This copper oxide can contaminate the
system (Figure 5-23). To prevent this, all the
air must be removed or purged from the tubing
during the brazing process. Purging is best
done using nitrogen. NEVER USE OXYGEN,
REFRIGERANT, OR COMPRESSED AIR TO
PURGE TUBING. AN EXPLOSION CAN RESULT WHEN OIL AND OXYGEN ARE MIXED.
When nitrogen is connected to and fed
through the lines being brazed, no oxides will
form. The nitrogen tank must be equipped with
a proper flow regulator (Figure 5-24). In addition, a pressure relief valve must be installed in
the feed line to limit the pressure to a safe level
for use in the equipment. The nitrogen regulator should be adjusted to the lowest pressure
that allows just enough nitrogen to flow to keep
air out of the tubing being brazed. As a rule of
thumb, the flow is sufficient when it can be felt
with the palm of your hand.
▼ Figure 5-22.
Double-Tip Torch
➧ WARNING
▼ Figure 5-23.
When Copper is Heated for Brazing, it Reacts
with the Oxygen in the Air to Form Copper Oxide
Inside the Tubing
COPPER OXIDE
SCALE WITHOUT
NITROGEN
▼ Figure 5-24.
Gauge-Equipped Pressure Regulator Used
with Nitrogen
TESTING/FEED LINE
PRESSURE GAUGE
CYLINDER
PRESSURE
GAUGE
CYLINDER
SAFETY
VALVE
PRESSURE
RELIEF
VALVE
NITROGEN
CYLINDER
PRESSURE
REGULATOR
HAND
VALVE
CONNECTED
TO EQUIPMENT
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
GAS PIPING AND FITTINGS
▼ Figure 5-25.
Follow all Local Codes when Installing Gas Pipe—
if None Exist, Follow the National Fuel Gas Code
Schedule 40, steel and wrought iron pipe are
commonly used for gas pipe. Stainless steel,
copper, and aluminum tubing can also be used
with gases that are not corrosive to them. When
selecting and installing gas pipe, always follow
all local codes (Figure 5-25). If no local codes
exist, follow the current issue of the National
Fuel Gas Code. Some important precautions
on pipe use are:
• Cast iron pipe cannot be used.
• Copper tubing cannot be used if the gas contains sulphur. To find out, check with the local
gas utility.
• Aluminum tubing should not be used in wet locations, or in outdoor or underground locations.
Aluminum tubing must be coated to protect against external corrosion in places where it is in
contact with masonry, plaster, and insulation. When moisture is present in the gas, aluminum
tubing should be used with caution.
• Plastic piping can be used in outside underground installations only.
Joints made in iron pipe may be threaded or welded, but in residential and light commercial
work, they are normally threaded. Copper and steel tubing can be joined by brazing using an
alloy containing not more than 0.05 percent phosphorus and having a melting point greater than
1,000° F. Flare fittings and compression fittings may also be used if permitted by local code, but
are normally prohibited in concealed locations. The fittings must be made of compatible materials. For iron and steel, fittings may be made of steel, brass, bronze, or iron. For copper, they
should be made of copper or brass, and for aluminum, they should be aluminum alloy.
The remainder of this section will focus on the procedures for joining iron and steel pipe.
al
Nationl
Fue
Gas
Code
Black Iron/Galvanized Steel Pipe
and Fittings
Black iron and galvanized steel pipe are similar. The difference between the two is that
galvanized pipe is zinc coated to prevent rusting. Steel pipe comes in various lengths and
sizes. In HVAC gas piping, threaded pipe ends
and malleable iron fittings are normally used to
make connections (Figure 5-26).
For pipe sizes below 12 inches, sizes are
expressed by the nominal inside diameter (I.D.).
Pipes with the same nominal size can have
walls of different thicknesses. Wall thickness in
HVAC applications is usually expressed by the
term Schedule, such as Schedule 40 or Schedule 80, where the thickness and strength of the
wall increase as the schedule number goes up
(Figure 5-27). For HVAC gas piping, Schedule
40 or standard weight pipe of the required size
is normally used.
Pipe and fittings threaded for American National Standard tapered threads are always
used for HVAC work because they produce a
leak-tight and mechanically rigid piping system.
Threads are expressed in terms of the nominal
pipe size, number of threads per inch, and the
thread series symbol. For example, the thread
specification 3/4 - 14 NPT means:
▼ Figure 5-26.
Steel Pipe Fittings and Components
TEE
UNION
90° ELBOW
ORDINARY COUPLING
FITTINGS
CLOSE
SHORT
NIPPLES
BUSHING
CAP
PLUG
PIPE ENDS
▼ Figure 5-27.
Comparison of 1" Pipe Wall Sizes
WALL
THICKNESS .133"
I.D.
1.0499"
STANDARD
(SCHEDULE 40)
WALL
THICKNESS .179"
O.D.
1.315"
I.D.
.9577"
EXTRA STRONG
(SCHEDULE 80)
O.D.
1.3155"
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
3/4 = 3/4-inch nominal thread diameter
14 = 14 threads per inch
NPT = American (National) Standard Taper
Pipe Thread
Cutting and Reaming Steel Pipe
One common method for measuring pipe is
called the face-to-face method (Figure 5-28).
As shown, the distance between the face of one
fitting to the face of a second fitting is measured.
To determine the length of pipe, add the depth
of thread engagement needed for each of the
fittings.
When cutting and threading pipe, secure the
pipe in a vise (Figure 5-29). A pipe cutter (not a
tubing cutter) is used to cut the pipe. The cut is
made by revolving the cutter around the pipe
and tightening the cutting wheel about 1/4 revolution with each turn. Avoid overtightening the
cutting wheel because this can cause a larger
burr to form inside the pipe and excessive wear
of the cutting tool wheel.
After the pipe is cut, remove any burrs with a
tapered reamer. Failure to remove burrs can
restrict the flow in a system.
Threading Steel Pipe
Tapered threads can be cut with a hand
threader (Figure 5-30) or electric pipe threader.
The use of a hand threader is described here.
If using an electric threader, operate it as directed by the manufacturer’s instructions. Hand
threaders are made up of two parts: the die and
the stock. The stock serves as the tool handle
and holds the die. The die cuts the threads. A
different die must be used for each size pipe.
To thread pipe using a manual stock and die,
proceed as follows:
1. Install the correct die for the size of pipe.
Make sure the die cutters are free of nicks
and wear.
2. Slide the die over the end of the pipe, guide
end first.
3. Using the heel of your gloved hand, firmly
push the die against the pipe, then slowly
rotate the die clockwise until enough threads
are cut to keep the die firmly on the pipe. At
this point, apply some thread cutting oil.
4. The number of threads to cut depends on
the size of the pipe. (See Table 5-1.) Make
sure to oil the die often. Also, back off (turn
counterclockwise) about 1/4 turn after each
full turn forward to clear metal chips from the
die.
5. When done cutting the threads, rotate the
die counterclockwise to remove it, being
careful not to damage the threads of the die
or the pipe.
6. Wipe off excess oil and chips from the pipe
threads with a rag to prevent cuts. Inspect
the clean pipe for burrs, chips, and scale, and
ensure that there are no damaged threads
that might leak.
▼ Figure 5-28.
Face-to-Face Pipe Measurement
FACE – TO – FACE
4'-6"
EXAMPLE:
PIPE LENGTH = 4'-6" + 2 x 5/8"
PIPE LENGTH = 4'-7 1/4"
5/8"
THREAD ENGAGEMENT
▼ Figure 5-29.
Pipe Vise and Cutting Tools
PORTABLE
PIPE-VISE
STAND
REAMER
PIPE
CUTTER
▼ Figure 5-30.
Manual Pipe Threading Tool
RATCHET HEAD
LOCK KNOB
DIE HEADS
DIE
HEAD
CUTTERS
MANUAL
CUTTER
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
Assembling Steel Pipe and
Fittings
When assembling joints in threaded pipe, a joint
compound, such as pipe dope, must be used.
If LP gases are being used, the compound must
be resistant to LP gases. The compound should
be applied sparingly to all male threads of all
joints (Figure 5-31) to prevent excess compound from getting inside the pipe. To avoid
contamination, do not apply the compound
to the last two threads closest to the pipe
opening. Do not apply compound to female
fittings. Do not use teflon tape for joining
pipes because particles of the tape may
break loose as the joint is made, contaminating the system.
Assemble the pipe joints in two phases; hand
tighten first followed by wrench makeup. Tightening of the pipe should be done using two pipe
wrenches, as shown in Figure 5-31. Generally,
about three threads should remain showing after the pipe and fitting have been joined.
PLASTIC PIPING AND
FITTINGS
▼ Table 5-1.
Determining the Number of Threads to Cut
➧ CAUTION
Approximate
Length of
Threaded
Portion (In.)
Approximate
Number of
Threads to
Cut
1/2
3/4
10
3/4
3/4
10
1
7/8
10
1-1/4
1
11
1-1/2
1
11
2
1
11
2-1/2
1-1/2
12
▼ Figure 5-31.
Apply Thread Compound Sparingly and Use Two
Wrenches when Tightening Pipe Joints
KEEP
INSIDE
CLEAN
Pipe Types and Sizes
Plastic pipe is made in basically the same nominal sizes and schedules as metal pipe. The
sockets of plastic fittings used to join the pipe
are recessed to a depth of about 1/2 inch to 5/
8 inch with shoulders at the end of the recess.
When measuring pipe lengths, always make
sure to take into account the depth of any fitting recesses up to the shoulder. Plastic pipe
and fittings used in HVAC work are normally
assembled using a special solvent-type cement. Plastic pipe can also be joined to steel
or copper pipe using adapters made for this
purpose (Figure 5-32). Four types of plastic
pipe are commonly used in HVAC work:
• PVC (polyvinyl chloride) – Rigid pipe with
high strength used in HVAC applications to
carry condensate water and flue gas.
• CPVC (chlorinated polyvinyl chloride) – Rigid
pipe with high strength used to carry cold
and hot water.
• PB (polybutylene) – Flexible pipe with good
strength used to carry cold and hot water. It
is commonly used in geothermal heat pump
ground loops.
• ABS (acrylonitrile-butadiene styrene) – Rigid
pipe with high strength used to carry water,
waste, and sewage and also used in drain
and vent applications.
Pipe Size
(In.)
PIPE COMPOUND
LEAVE THE LAST
TWO THREADS BARE
PIPE
THREADED
COUPLING
▼ Figure 5-32.
Adapter Used to Join Plastic and Steel Pipe
STEEL
PIPE
COUPLING
ADAPTER
PLASTIC
PIPE
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
Cutting and Joining
To cut and join ABS, PVC, or CPVC pipe,
proceed as follows:
1. Use a plastic tubing cutter or a special cutter
called a plastic tubing shear to cut the pipe
(Figure 5-33). Once cut, deburr using a knife
or file. Do not use a cut-off saw to cut the
pipe. It will leave particles inside the pipe
which can cause clogs.
2. Check the dry fit and alignment of the pipe
and fitting. The pipe should easily go 1/3 of
the way in.
3. Using a pipe cleaning solvent recommended
for use with the cement, thoroughly clean the
pipe end and the inside of the fitting socket.
4. Apply a thin coat of cement to the entire inside surface of the fitting socket (Figure 5-34)
and to the end of the pipe equal to the depth
of the socket.
5. Immediately after applying the cement to the
parts, push the pipe completely into the fitting socket using a 1/4-turn twisting motion
until the pipe bottoms in the socket and completely spreads the cement.
▼ Figure 5-33.
Plastic Pipe Cutting Tools
➧ CAUTION
TUBING SHEAR
CUTTER
▼ Figure 5-34.
Cementing Plastic Pipe
BRUSH ON ADHESIVE
JOIN AND TWIST
1/4 TURN
ALIGNMENT
MARKS
QUICK NOTE
If the alignment of the plastic pipe and fitting being joined is critical, mark a line across both parts
while the assembled joint is being dry-fitted. This line can be used later to properly align the pipe and
fitting when they are permanently assembled with cement.
PIPING SYSTEMS 5
Table of Contents
Map
References
Section Topics
PIPE HANGERS AND
SUPPORTS
Piping and tubing can be supported using a variety of hangers or supports (Figure 5-35). Used
at the necessary intervals, they keep the piping in alignment and prevent sagging or
accidental movement. Hangers and supports
must be installed in a manner that does not interfere with the free expansion and contraction
of the piping between anchors. When installing
pipes, always refer to local gas codes and other
codes for specific requirements. Piping should
never be supported by other piping in the
building.
Table 5-2 gives some guidelines for typical
spacing of pipe hangers and supports used with
steel pipe and copper tubing. For rigid plastic
lines, support is generally provided about every three to five feet.
Hangers and wall brackets used to support
refrigerant piping normally have a vibration-absorbing material between the support and the
pipe. When piping must pass through a wall,
roof, or ceiling, it must run through an adequately sized sleeve. There should be enough
room within the sleeve for the pipe and for any
pipe insulation. Any remaining open space in
the sleeve should be stuffed with insulation.
Where the sleeve meets the surface, caulk
should be applied.
▼ Figure 5-35.
Common Hangers and Supports
CLEVIS HANGER
SINGLE HOOK
RING HANGER
LIGHT STRAP
▼ Table 5-2.
Typical Pipe/Copper Tubing Support/Hanger
Spacing
Spacing Between Hangers/Supports (Ft.)
Pipe Size
Standard Steel Pipe
Copper Tubing
Water
Gas
Water
Gas
1/2
7
6
5
4
3/4
7
8
5
6
1
7
8
6
8
1-1/2
9
10
8
—
2
10
10
8
—
2-1/2
11
10
9
—
C-CLAMP
RISER CLAMP AROUND PIPE
FORCED-AIR DUCT SYSTEMS 6
▼ FORCED-AIR DUCT SYSTEMSS
SECTION 6
INTRODUCTION
Residential or light commercial cooling/heating installations often require that the HVAC technician install new duct systems or change existing ones. Proper installation of the air distribution
system is critical to the correct performance of the related heating/cooling equipment. The focus
of this section is on the techniques used for installing duct systems and components. Also covered are conditions in a duct system that can cause problems. This section is not intended to
teach air system theory or duct design; it presumes that the proper type of equipment and ductwork
have been selected and purchased for the job by a qualified engineer or salesperson based on a
survey of the job.
FORCED-AIR DUCT SYSTEM MENU
The Basic Air Distribution System
Galvanized Steel Ductwork Systems
Trunk and Branch Ducts
Fittings and Transitions
Supply Outlets and Return Grilles
Volume Dampers
Installation Guidelines
Flexible Ductwork
Fiberglass Ductwork
System Fans
Changing Fan Speed
Balancing the Air System
Thermometer Balancing for Heating
Thermometer Balancing for Cooling
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
THE BASIC AIR
DISTRIBUTION SYSTEM
There is a great diversity in residential and light
commercial forced-air distribution systems and
equipment, but they all have the same basic
components (Figure 6-1). All systems, no matter how complex, can be divided into three
functional areas:
• Ductwork system – Includes the supply and
return trunk ducts and all the branch or runout
ducts.
• Air distribution system – Includes the conditioned space supply diffusers and return air
grilles.
• Fan system – Includes the blower and motor in the furnace or fan coil.
Depending on the climate and design of the
building, duct systems can be installed in basements, crawl spaces, open areas, closets,
attics, and imbedded in concrete floors (slabs).
Ducts can be made from various materials, but
galvanized sheet metal, fiberglass ductboard,
and metallic or nonmetallic flexible ductwork are
the most common.
Building codes pertaining to the installation
of air distribution systems vary widely. The National Fire Protection Agency (NFPA) Standard
90B, Council of America Building Officials
(CABO) One- and Two-Family Dwelling Code,
or a local code are commonly used for duct systems in single-family dwellings. NFPA Standard
90A is used in most localities for multi-family
homes. You must be aware of and follow all
relevant codes.
▼ Figure 6-1.
Basic Air Distribution System
CONDITIONED
SPACE
RETURN
GRILLE
SUPPLY
DIFFUSER
SUPPLY
AIR DUCT
RETURN
AIR DUCT
FAN
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
GALVANIZED STEEL DUCTWORK SYSTEMS
Trunk and Branch Ducts
Rectangular or round galvanized steel duct is commonly used in air distribution systems. Standard duct sizes are readily available. Figures 6-2 and 6-3 show the components that are commonly
used with rectangular and round duct systems. Standard lengths are available for both. The
thickness of metal duct is expressed as its gauge. Rectangular and round ducts of 24 to 30 gauge
are used for residential and light commercial installations. The larger size ducts have thicker,
more rigid walls to prevent them from making popping-like noises when the system blower starts
and stops. The sizes of the various ducts used in a system is determined by the maximum volume
of air in CFM that must flow through each section of duct. Tables for sizing duct based on airflow
in CFM are located on pages 156 and 157 of this book.
▼ Figure 6-2.
Typical Rectangular Duct System Components
▼ Figure 6-3.
Typical Round Duct System Components
MAIN DUCT
1
1
MAIN DUCT
2
PLENUM
PLENUM
6
4
2
7
5
AIR
HANDLER
CONNECTS PLENUM TO
MAIN DUCT
2. TAKEOFF
4. ROUND PIPE
BASIC AIR CARRIER FOR
MULTIPLE APPLICATIONS
5. 90 ELBOW
CONNECTS RECTANGULAR
DUCT TO PIPE OR FLEX DUCT
3. REGISTER/STACK BOOT
CONNECTS PIPE OR FLEX DUCT
TO REGISTER OR STACK
6
AIR
HANDLER
3
1. STARTING COLLAR
8
5
3
ADJUSTABLE. USED TO CHANGE
DIRECTION OF FLOW UP TO
90°
6. DAMPER
REGULATES AIRFLOW
THROUGH DUCTS
7. FLEX DUCT
INSULATED. READY TO INSTALL
4
1. STARTING COLLAR
CONNECTS PLENUM TO
MAIN DUCT
2. TAKEOFF
CONNECTS RECTANGULAR
DUCT TO PIPE OR FLEX DUCT
3. WYE BRANCH
CONNECTS MAIN DUCT TO
BRANCH
4. FLEX DUCT
INSULATED.
READY TO INSTALL
7
5. TEE JOINT
CONNECTS MAIN DUCT TO
BRANCH
6. ROUND PIPE
BASIC AIR CARRIER FOR
MULTIPLE APPLICATIONS
7. REGISTER/STACK BOOT
CONNECTS PIPE OR FLEX DUCT
TO REGISTER OR STACK
8. REDUCER/INCREASER
TO REDUCE OR INCREASE SIZE
BETWEEN DIFFERENT DIAMETER
PIPES
Fittings and Transitions
Fittings such as elbows, angles, takeoffs, and boots change the direction of airflow or change its
velocity. Transitions are typically used to change from one size or shape duct to another. Because
each fitting or transition installed in a duct run adds friction and reduces the quantity of air the duct
can carry, the use of unneeded fittings or fittings not suited for the job must be avoided. For the
same reason, the path for all duct runs should be as direct as possible.
The pressure drop for each type of fitting is known and is expressed as an equivalent length of
straight duct value. The assigned value is equal to the pressure drop of a specific number of feet
of straight duct length of the same size. Duct designers use these values when calculating the
external static pressure of a system. External static pressure is discussed later in this section.
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
Supply Outlets and Return Grilles
The locations and types of supply outlets and
return grilles used in a system is determined
by the climatic conditions for which the system
is designed. Air distribution systems designed
for cold climates will usually have supply and
return air openings located low in the rooms to
provide warmth at the walls and floors in the
winter. This allows the heated air to rise into
and heat the rooms (Figure 6-4). Air systems
designed for hot climates will usually have supply and return air openings located high in the
rooms to allow the heavier cool air to fall into
and cool the rooms. Systems designed for moderate climates may use either design, or a
compromise between the two.
Supply air outlets (diffusers) provide the
proper air motion in a room and blend the supply air with the room air so that the room is
comfortable without excessive noise or drafts.
The size of each diffuser is based on the volume of air in CFM that is supplied from the
outlet. Tables for sizing diffusers and grilles
based on airflow in CFM are located on page
156 of this book. Five types of supply diffusers
are commonly used (Figure 6-5). Baseboard,
floor, and low sidewall diffusers are used mainly
in heating systems; high sidewall and ceiling
diffusers are used mainly in cooling systems.
For proper operation, diffusers should be
mounted at the ends of branch ducts. They
should not be mounted directly on the main
ductwork. Proper operation is based on each
diffuser receiving a flow of non-turbulent air in
a straight line. If attached directly to a main duct,
the diffuser will shoot turbulent air out at an
angle, causing it to be noisy. Also, the volume
of air will be incorrect, making system balancing difficult. If it is necessary to install a diffuser
in an extremely short branch run, turning vanes
or a scoop should be installed in the run to
straighten out the air before it enters the diffuser. Most diffusers are equipped with built-in
dampers. These dampers should never be considered as a substitute for a branch volume
damper. Diffuser dampers are intended only to
apply or shut off airflow to a room.
Return grilles are similar to supply diffusers,
except they normally do not have deflection or
volume control devices. Return air grilles are
mounted in locations that are compatible with
the supply outlets and ductwork. In heating systems, return grilles are ideally installed where
the coolest air in the area will be returned. Similarly, in cooling systems, they are installed
where the warmest air will be returned. Never
install return air openings in bathrooms or
kitchens because they will spread odors
throughout the building by way of the
ductwork system (Figure 6-6).
▼ Figure 6-4.
Supply and Return Air Openings in Cold and
Warm Climate Air Systems
COLD
CLIMATE
LOW SUPPLY
AND RETURN
AIR OPENINGS
TO PROVIDE
WARMTH IN
WINTER
WARM
CLIMATE
HIGH SUPPLY
AND RETURN
AIR OPENINGS
TO PREVENT
HOT AIR
STRATIFICATION
IN SUMMER
▼ Figure 6-5.
Supply Diffusers
BASEBOARD
LOW
SIDEWALL
FLOOR
COLD CLIMATE DIFFUSERS
HIGH
CEILING
SIDEWALL
WARM CLIMATE DIFFUSERS
▼ Figure 6-6.
Avoid Odor Pollution
➧ CAUTION
DOOR
BATHROOM
SUPPLY
AVOID ODOR POLLUTION. DO NOT INSTALL RETURN
IN BATHROOM. EXHAUST ODORS. PROVIDE UNDERCUT
AT DOOR. SUPPLY AS USUAL.
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
Volume Dampers
Volume dampers are used to adjust the amount
of airflow through the branch runs of an air distribution system. Without dampers, air cannot
be properly distributed and balanced, causing
some rooms to receive too much air while others do not receive enough. Dampers should be
installed in an accessible place in each branch
supply duct as close to the main duct or supply
air plenum as possible (Figure 6-7). Otherwise,
significant turbulence and noise will be transmitted into a room via the room diffuser.
Simple butterfly dampers with manual adjustments are normally used in single-zone heating/
cooling systems. Dampers used in multiplezone systems are usually automatically
controlled by a damper motor.
▼ Figure 6-7.
Dampers
ZONE - SYSTEM
AUTOMATIC
DAMPER
MANUAL
DAMPER
DAMPER
ACTUATOR
RETURN
Installation Guidelines
Before installing ductwork, study the system layout diagram and the building’s construction to
determine the best approach. Make sure to use
all the ductwork parts exactly as specified by
the system designer. Do not substitute different duct sizes, fittings, etc. as their use could
alter the system design enough to prevent
proper system operation. The methods used
to install all metal duct systems are similar.
Guidelines for the installation of a simplified
extended plenum ductwork system
(Figure 6-8) are given here. They involve the
installation of the following components:
• Supply trunk starting collar on the plenum
• Supply and return main trunk ducts
• Branch supply ducts and room diffuser boots
• Branch return ducts and return grille boots
• Supply diffusers and return air grilles
Installing the Plenum and Supply Trunk
Starting Collar – When installing the plenum
and supply trunk starting collar, follow these
basic guidelines:
1. Temporarily place the prefabricated plenum
in position on the furnace or air handler.
2. From the system layout diagram, determine
where the supply trunk duct starting collar
should attach to the plenum.
3. Using a template (Figure 6-9), mark the location where the collar must be installed.
4. Cut the collar opening by first drilling or
punching a hole inside the marked area to
be cut, then use tin snips (Figure 6-10) to cut
the opening. Follow around the marked outline. Use dividers or a hole cutting tool for
making round takeoffs.
5. Place the collar in the opening of the plenum, then secure by bending the metal tabs
flat against the inside of the plenum. If installing more than one starting collar on a
plenum, they should all be mounted at the
same height on the plenum.
6. Correctly position the plenum on the furnace
or air handler and attach using sheet metal
screws.
HANDLE
MANUAL
BALANCING DAMPER
NEAR MAIN SUPPLY
EASILY ACCESSIBLE
SUPPLY
DIFFUSER
VOLUME
DAMPER
WIDE
OPEN
▼ Figure 6-8.
Simplified Extended Duct System
▼ Figure 6-9.
Using a Template to Outline Openings to be Cut in
a Plenum
TEMPLATE
PLENUM
STARTING COLLAR
ASSEMBLED TO
PLENUM
FURNACE
SHEET METAL
SCREWS
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
Installing the Main Supply and Return Air
Trunks – Start at the furnace or air handler.
Rectangular trunk ducts are usually run at right
angles to the building’s floor joists, allowing the
branch ducts to run between the joists. The sections can be supported by strap, trapeze, or
rod hangers. Be sure to leave a minimum
clearance of at least one inch between the
supply ductwork and the bottom of the
joists. This is necessary for fire prevention.
Joints in round duct trunk systems are normally
fastened together with sheet metal screws.
Rectangular ducts can be purchased with builtin snap joints (Figure 6-11) for quick assembly
or can be fastened together using S-type connectors and drive clips as described below.
1. Put an S-type connector over both long
(transverse) edges of the first duct section.
Make sure the connector ends are flush with
the sides of the duct.
2. Align the next section of duct with the preceding one so that its long edges are started
into the S-type connector slots. Firmly push
the duct so that it is completely seated in the
slots of the S-type connector.
3. Use drive clips to fasten the two short sides
of the joint. Bend the tab on one end of the
clip inward 90°. Put the clip upward over the
duct edges and tap it with a hammer to drive
it in place, then bend the top tab down over
the duct.
4. Duct fasteners make a nearly airtight connection. If further sealing is needed, tape the
joint with approved duct tape.
Air that flows into a trunk duct elbow, takeoff, etc. becomes quite turbulent downstream
from the device and requires a few feet of
straight, uninterrupted airflow for the turbulence
to diminish. When takeoffs and other parts are
installed too close together, air turbulence can
build up and cause the system to become noisy.
To reduce turbulence and prevent noise in the
extended plenum system, the first branch takeoff should be made at least 18 inches away
from the beginning of the trunk duct
(Figure 6-12). Also, the end of the trunk should
extend at least 12 inches beyond the takeoff
for the last branch.
▼ Figure 6-10.
Sheet Metal Cutting Snips and Shears
AVIATION SNIPS
(CUT STRAIGHT)
AVIATION SNIPS
(CUT LEFT)
ELECTRIC SHEAR
AND BLADES
AVIATION SNIPS
(CUT RIGHT)
STRAIGHT SNIPS
▼ Figure 6-11.
Rectangular Duct Installation
KEEP A MINIMUM DISTANCE OF AT LEAST ONE INCH
BETWEEN SUPPLY DUCTS AND JOISTS OR OTHER
COMBUSTIBLES
JOIST
DRIVE CLIP
IN PLACE
1"
TAB
BENT OVER
DRIVE CLIP
S-TYPE
CONNECTOR
SNAP END
SNAP JOINT
▼ Figure 6-12.
Guidelines for Installing an Extended Plenum
Duct System
TRUNK
12" MINIMUM
BALANCING DAMPER
TAPERED BRANCH
TAKEOFF
FLEX
CONNECTOR
24 FEET MAXIMUM
18"
MINIMUM
TAPERED MAIN
SUPPLY TAKEOFF
AIR
HANDLER
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
An extended plenum duct system works best
when the length of its supply and/or return trunk
ducts do not exceed 24 feet. When trunks
longer than 24 feet are needed, a reducing extended plenum duct system (Figure 6-13)
should be used. As shown, the length of the
first trunk section should not be longer than 15
to 20 feet. The size of the duct used in each
succeeding section becomes smaller because
it carries less air. The length should not exceed
24 feet. Generally, a reduction in trunk duct size
is made after every three branch duct connections. Single-taper transitions are used to
reduce from the larger to smaller duct size. To
allow the air turbulence resulting from the transition to diminish before the air enters the next
branch duct, the first branch duct takeoff downstream of the transition should be located at
least four feet away from the transition.
Installing the Branch Supply Ducts and
Return Ducts – When the main trunk ducts are
installed in the ceiling of a basement or crawl
space, round branch ducts are normally run to
the first floor supply air diffusers and return air
grilles via the space between the floor joists
(Figure 6-14). In multi-story buildings, the upper floor supply and return branches are
connected to the trunk ducts by combining
round ducts within the floor joists with stack
ducts installed in the interior walls.
The size of the round duct used in each
branch run is determined by the quantity of air
it must carry. Depending on the system application, and for ease of installation, many duct
designers will make compromises and choose
to use a standard size round duct to feed all
branches. Good practice requires that the smallest size round duct used for any branch duct to
major rooms (all but bathrooms, foyers, etc.)
be at least six inches. The duct used for partition wall stacks can be 2-1/4 or 3-1/4 inches
thick with widths from 10 to 14 inches.
Although not recommended, it is sometimes
necessary to run wall stacks up outside walls
or in walls next to unconditioned spaces
(Figure 6-15). To avoid unacceptable losses in
heating or cooling capacity, the thinner 2-1/4inch stack duct typically is used to allow at least
one inch of insulation to be installed between
the duct and the outside wall. The disadvantage of using this smaller size stack is that it
can only carry about 70% of the air that a 3-1/
4-inch duct can carry.
▼ Figure 6-13.
Guidelines for Installing a Reducing Extended
Plenum Duct System
24 FEET
MAXIMUM
BALANCING
DAMPER
15-20 FEET
MAXIMUM
12" MIN.
TAPERED
BRANCH
TAKEOFF
4 FEET MIN.
TAPERED MAIN
SUPPLY TAKEOFF
FLEX
CONNECTOR
AIR
HANDLER
4'
REDUCING
TRANSITION
▼ Figure 6-14.
Typical Branch Duct Routing
STUD STOP
GRILLE
RETURN
PARTITION
WALL RETURN
6" ROUND
SUPPLY
RUNOUT
SUPPLY
DIFFUSER
31⁄4 x 10"
WALL
STACK
(SUPPLY)
JOIST
STOPS
R
BALANCING
DAMPER
S
6" ROUND SUPPLY
BRANCH DUCT
PANNED JOIST
RETURN BRANCH
RETURN TRUNK DUCT
SUPPLY TRUNK DUCT
RETURN DROP DUCT
SUPPLY PLENUM
FURNACE
▼ Figure 6-15.
Installation of Outside Wall Stack Duct
1-INCH
FOAM BOARD INSULATION
FIBERGLASS
INSULATION
OUT
S
WAL IDE
L
21⁄4 x 12" STACK DUCT
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
When local codes permit, framing spaces are
often used as return ducts. As shown in
Figure 6-16, the wall space between the studs
can be used as a return stack duct for a highwall return air grille or for a return stack
connecting the first floor with an upper floor.
Wooden or sheet metal stops must be installed
to seal off the stud space from the rest of the
area. In a like manner, the bottom of a floor
joist space on any floor may be covered with
sheet metal and its ends sealed to use the
space as a return air duct. This is referred to as
a panned return duct.
Branch duct installation involves cutting
openings in the supply and return ducts to
mount takeoffs and other fittings. The holes for
these devices are marked and cut, and the
devices mounted on the trunk ducts using the
takeoff for a marking template.
When assembling branch runs, the last section of duct usually must to be cut to fit. If using
round duct crimped on one end, cut the excess
length from the plain end. Make sure to add
about two inches to the measured length to allow for insertion of the crimped end into the boot
or elbow. Then swing the boot or elbow up or
down to connect to the boot extension
(Figure 6-17). If it is not possible to swing a
boot or elbow to make the connection, cut the
round duct just long enough to fit with no overlap, and fasten the joint with a drawband. If
cutting rectangular duct, add enough to the
measured length at the transverse edges to slip
into the S-type connector and enough on the
sides to form drive tabs.
Running branch ducts to the various rooms
can involve considerable cutting of access holes
in the building’s structure. In new construction,
the process is easier because everything is
open and visible. In renovation and remodeling jobs, it is much more difficult and mistakes
can be costly.
Installing Supply Diffusers and Return
Grilles – Compromises are almost always
made by system designers to gain a uniform
appearance in a building when selecting diffusers and grilles. Diffusers and return grilles
should be installed as recommended by the
manufacturer.
A properly sized branch duct and diffuser reduces the velocity of the airflow in the branch.
This results in quiet diffuser operation. Installation of an undersized diffuser will cause it to be
noisy. For example, a diffuser rated at 110 CFM
should not be connected to a duct supplying
150 CFM. An oversized diffuser can be used,
but it is important to remember that the maximum amount of air it can supply is limited by
the capacity of the branch duct feeding it. For
example, a diffuser rated at 110 CFM can only
supply 100 CFM of air when the branch duct
feeding it has a maximum capacity of 100 CFM.
▼ Figure 6-16.
Stud and Joist Space Returns
STUD STOP
SHEET METAL
PANNING
RETURN MAIN
ALL
NW
IO
RTIT
PA
OPENING TO
RETURN TRUNK
OR STUD SPACE
JOIST
STOP
FLOOR
SHEET METAL PANNING
ON JOIST BOTTOM
JOIST STOP
▼ Figure 6-17.
Assembling the Last Section of a Branch Duct
MOUNT TOP OF BOOT EXTENSION
FLUSH WITH TOP OF FLOOR
DUCT SECTION
CUT TO FIT
BOOT
EXTENSION
PUSH OR SWING UP TO CONNECT
TO THE BOOT EXTENSION
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
QUICK NOTE
General guidelines to follow when cutting access holes:
• Never assume that one building is constructed the same as a similar one.
• Always plan and measure carefully before attempting to cut any hole. Make a template to ensure
that the opening will be of the correct size and shape.
• Make sure the hole will not weaken the structure. Provide temporary support for structural parts you
will cut.
• When a portion of a joist or stud must be removed, always install a header of equal size to reinforce
the area being cut.
• Use shallow blade settings or short blades to avoid cutting plumbing and/or electrical wires.
• Cut holes slightly larger than the duct or fitting to give enough room for adjusting and fastening.
• Be extra careful when cutting plaster to prevent leaving a ragged edge that the flange on a diffuser
or grille cannot cover. Do not force the saw.
Noise and Vibration Control – A ductwork system must be supported so that it does not sag
or move. Duct movement can occur when the
fan starts as a result of the rush of air through
the system. Metal ductwork also moves as a
result of expansion and contraction. Strap or
trapeze hangers (Figure 6-18) are commonly
used to support ductwork at the joints in the
duct, which are the weakest points. Your job as
an installer is to hang the duct according to the
designer’s plans. If needed, specific requirements for supporting duct can be found in the
HVAC Duct Construction Standards published
by SMACNA.
Metal duct with duct liner insulation on its interior, or fiberglass duct, can be used to absorb
noise within the ducts. Duct liner is normally
installed by the duct manufacturer or fabricator. It serves the purpose of providing both
thermal and sound insulation. To carry the same
volume of air, lined duct must be larger than
unlined duct to account for the thickness of the
liner. For example, when the thickness of the
duct liner is one inch, a lined duct of 12 x 8
inches delivers the same amount of air as an
unlined duct that is 10 x 6 inches.
Ductwork systems must not transmit machine
vibrations into the conditioned space. To help
prevent this, a flexible connector can be installed where the supply and return ductwork
connects to the air handler unit (Figure 6-19).
Flex connectors should be installed so that they
are not stretched so tight that they lose their
flexibility nor so loose that they sag and block
part of the airstream. Air handling equipment
that is suspended from floor joists, roof rafters,
etc. should use vibration-eliminating hangers.
Without them, the unit vibration can be carried
directly into the building and travel through the
structure.
▼ Figure 6-18.
Strap and Trapeze Hangers
HANGER
STRAPS
DUCT
STRAP HANGER
STRAP OR
ANGLE
ROD
DUCT
TRAPEZE HANGER
▼ Figure 6-19.
Ductwork Vibration Control
SUPPLY
MAIN
RETURN
MAIN
FLEX CONNECTOR
AIR
HANDLER
OR
FURNACE
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
Installation of Insulation and Vapor
▼ Figure 6-20.
Use of Duct Insulation and a Vapor Barrier in an
Barriers – Any duct system that runs through
Unconditioned Space
an unconditioned space should be insulated if
a temperature difference greater than 15° F can
exist between the conditioned air in the duct
EXTERIOR INSULATION
SLEEVE WITH VAPOR BARRIER
and the ambient air outside the duct. This con(JOINTS TAPED)
dition is common when ductwork passes
FLOOR OVER
VENTED CRAWLSPACE
through a ventilated crawlspace, attics, gaFLOOR JOIST
rages, or other unconditioned spaces (Figure
(INSULATED)
6-20). Insulation is necessary to prevent the
METAL
transfer of heat between the air in the duct and
BRANCH DUCT
the air in the unconditioned space. The duct in
SHEET METAL MAIN DUCT
systems with a cooling mode must also have a
WITH INSULATING DUCT
properly sealed vapor barrier to prevent the
LINER (JOINTS TAPED)
ductwork from sweating, causing corrosion of
the duct, insulation degradation, and/or water
damage to the structure.
Where fiberglass ductboard is used, the insulation and vapor barrier is the duct itself. Fiberglass duct is covered in more detail later in this section. Metal ductwork can be insulated either
externally, or on the inside with duct liner (Table 6-1). Use of lined duct with taped joints eliminates
the need for additional vapor sealing. For non-lined duct, the insulation/vapor barrier can be
applied externally, after the ductwork has been installed. The insulation includes a foil or vinylbacked vapor barrier and comes in several thicknesses. Branch ducts made of sheet metal are
insulated using the same materials. It is important to seal all vapor barrier joints and holes with
tape to prevent any moisture from condensing on the duct.
yyyyyyyyyyyyy
,,,,,,,,,,,,,
,,,,,,,,,,,,,
yyyyyyyyyyyyy
,,,,,,,,,,,,,
yyyyyyyyyyyyy
,,,,,,,,,,,,,
yyyyyyyyyyyyy
,,,,,,,,,,,,,
yyyyyyyyyyyyy
▼ Table 6-1.
Advantages and Disadvantages of Lined Versus Wrapped Metal Duct
Advantages
Lined
Wrapped
Disadvantages
Easier to install
Quieter
Insulation damage unlikely
Higher cost
Higher friction loss
Lower cost
Lower friction loss
More difficult to install
Insulation damage more likely
Noisier
ASHRAE standards specify the minimum acceptable value (R-value) of insulation that must
be used for insulating duct. Figure 6-21 shows
the formula used in the ASHRAE standard to
determine the needed R-value and an example
of its use. Normally, this value will be determined ahead of time for you. As a rule of thumb,
the equivalent R-value for one inch of insulation is about R-4. Even though return duct
systems have less difference in air temperature than supply ductwork, it is recommended
that they also be insulated.
▼ Figure 6-21.
Example of a Method Used to Determine the
Thickness of Duct Insulation
RO
OF
ATTIC: 120° F
TRU
SS
INSULATED FLEX DUCT
SUPPLY
55° F
LINED SHEET
METAL DUCT
RAFTERS AND INSULATION
75° F ROOM
TDDUCT = 120 - 55
= 65° F
R = TD/15
= 65/15
= 4.3
CEILING
1"= ABOUT
R4
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
FLEXIBLE DUCTWORK
Flexible duct is commonly used as branch duct
in unconditioned spaces such as attics
(Figure 6-22) and in spaces where obstructions
make the use of rigid duct difficult or impossible. Flexible duct is not recommended for use
in the return side of a system. Both metallic and
nonmetallic insulated and non-insulated forms
of flexible round duct are manufactured in standard duct sizes and lengths and can be easily
cut to the length needed.
Sections of flexible duct can be joined using
coupling sleeves. Flexible duct is fastened to
metal ducts or connectors using a drawband
(duct strap) and a tightening tool to fasten it
(Figure 6-23). When making connections, collars, sleeves, etc. should be inserted into the
flexible duct at least one inch before fastening.
For insulated duct, the insulation is fitted over
the connection and fastened with a duct strap
or tape.
Long runs of flexible duct are not recommended. Even when properly installed, most
flex duct causes at least two to four times as
much resistance to airflow as the same diameter sheet metal duct. Duct runs should be kept
as straight and short as possible (Figure 6-24).
Gradual bends should be used, because tight
turns will greatly reduce the airflow and may
even cause the duct to collapse. Flexible duct
should be supported with one-inch or wider
bands with a minimum of sag between the supports (Figure 6-25). Some flexible duct comes
with built-in eyelet holes for hanging the duct.
If a connection to a ceiling diffuser requires
a bend, it is better to use an insulated metal
elbow at the input to the diffuser than to bend
flexible duct to form the connection. When using flexible duct to make very short duct runs
between diffusers and takeoffs on a supply duct,
the vertical alignment of the flexible duct run is
critical and should be plumb. If not, diffuser
noise will increase and air will shoot out to one
side of the diffuser rather than being distributed
evenly.
▼ Figure 6-22.
Typical Use of Flexible Duct
ATTIC – EXTENDED PLENUM SYSTEM
FLEXIBLE DUCT
AIR HANDLER
SUSPENDED
FROM ROOF
▼ Figure 6-23.
Connecting Flexible Insulated Duct to a Metal
Collar
METAL
COLLAR
▼ Figure 6-24.
Make Straight Runs and Gradual Turns with
Flexible Duct
SUPPLY
AIR
NOT THIS
BALANCING
DAMPER
CEILING FRAMING
THIS
BALANCING
DAMPER
NOT THIS
(DIFFUSER
BELOW
CEILING)
METAL ELBOW
(INSULATE)
THIS
▼ Figure 6-25.
Supporting Flexible Duct
5' - 0" MAXIMUM
SAG 1/2" PER FOOT
OF SUPPORT SPACING
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
FIBERGLASS DUCTWORK
Fiberglass duct can be used almost anywhere that metal duct can. It has more friction loss than
metal duct, but has the advantage of being quieter and has a built-in vapor barrier. Fiberglass
duct is available in flat sheets (ductboard) for fabricating rectangular duct and duct fittings. Some
fittings such as elbows require the installation of metal accessories such as turning vanes to
achieve proper airflow.
Fiberglass duct systems must be properly supported or they will sag. Hangers should not cut
the outside cover of the ductboard. Follow the ductboard manufacturer’s recommendations for
supporting the ductwork. Guidelines are also given in SMACNA’s standards for Fibrous Glass
Duct Construction.
Aluminum-backed ductboard is made in different sizes; 1-inch thick, 4 x 10-foot boards are the
most common. Ductboard manufactured with male and female shiplap joints along the 10-foot
edge are normally used so that when formed into a rectangular duct section, the finished 4-foot
duct has male and female joints at its ends to connect to other straight sections or fittings.
Fabrication of ductboard into straight sections
▼ Figure 6-26.
and fittings is done with either special automatic
Ductboard Manual Fabrication Tools
grooving machines or manually with hand
grooving tools. Hand tools are color coded to
identify the kind of groove they cut
(Figure 6-26). Fabrication of straight duct sections and fittings can be done in several ways;
always follow the ductboard manufacturer’s instructions. Additional information can be found
in SMACNA’s standards for Fibrous Glass Duct
Construction.
ORANGE TOOL
Figure 6-27 shows the various cuts needed
TYPICAL TOOL
CUTS MODIFIED SHIPLAP FOR
to fabricate a rectangular duct section.
(ORANGE TOOL)
FORMING CORNERS
Figure 6-28 shows how a 90° elbow is fabricated using fiberglass ductboard. Connections
are made with a combination of outward-clinch
staples and special heat-activated tape.
GRAY TOOL
CUTS FEMALE SHIPLAP
PURPLE TOOL
CUTS MALE SHIPLAP
RED TOOL
CUTS "V" OR MITER FOR
FORMING CORNERS
BLUE TOOL
CUTS SHIPLAP FOR FORMING
CLOSING CORNER JOINTS.
ALSO CUTS INSULATION
TO BE STRIPPED FROM
STAPLING FLAP
QUICK NOTE
Be careful when carrying 4 x 10-foot
sheets
of ductboard. Support the board
overhead with hands spread lengthwise
(not across the width).
▼ Figure 6-27.
Fabricating a Straight Duct Section
▼ Figure 6-28.
Mitered 90° Elbow
BEVELED
CUTS (45°)
D
C
A
B
TURNING
VANE
FOLDED DUCT
CORNER FOLD
GROOVES
ORANGE TOOL
GRAY TOOL
"R"
A+13/4"
"L"
B+13/4"
C+13/4"
A, B, C, AND D ARE INSIDE DIMENSIONS
BROAD BLADE
KNIFE OR
BLUE TOOL
STAPLING FLAP
11/2"
"R"
D+13/8"
REINFORCEMENT
TAPE STRIPS
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
SYSTEM FANS
The system fan (blower) in the system’s furnace, fan coil unit, etc. must provide the
pressure needed to overcome the sum of the
friction losses for the ductwork and other components such as evaporators, electronic air
cleaners, etc. in the system that are not included
in the fan rating (Figure 6-29). The total pressure loss of the duct system components
external to the fan assembly is called the external static pressure and is normally expressed
in inches water gauge (in. w.g.) or inches water column (in. w.c.). Duct system designers use
the friction loss to select equipment that has a
fan capable of supplying the correct amount of
air through the designed duct system.
Two types of fans are commonly used: direct-drive and belt-drive (Figure 6-30). Most
residential equipment uses multi-speed directdrive fans. The fan speed can be selected to
provide the proper amount of air needed for
operating the system in the heating and cooling modes. Belt-drive fans are more likely to
be encountered in light commercial packaged
products. The fan speed can be changed by
adjusting the pulley diameter.
CHANGING FAN SPEED
▼ Figure 6-29.
Duct System Total Friction (External Static
Pressure Loss)
1
3
CONDITIONED
SPACE
2
TOTAL FRICTION LOSS = 1 + 2 + 3
1 = SUPPLY SYSTEM LOSS
2 = RETURN SYSTEM LOSS
3 = COMPONENTS NOT INCLUDED IN FAN RATING
▼ Figure 6-30.
Direct-Drive and Belt-Drive Fans
SPEED
SELECTION
TAPS
ADJUSTABLE
PULLEY
1
2
3
4
DIRECT-DRIVE BLOWER
BELT-DRIVE BLOWER
Fan speed may need to be changed or adjusted at the time of installation to provide the required
quantity of air.
If the system has a direct-drive motor, the speed can be adjusted by changing the speed taps
on the blower motor.
If the system fan is belt-driven, the speed can be increased by narrowing the width of the pulley
V-groove, or decreased by widening the width of the pulley V-groove. Typically, variable-pitch
pulleys allow the speed of the driven fan to be varied by as much as 30 percent.
The manufacturer’s installation literature should contain tables detailing the adjustable pulley
settings required to achieve a certain CFM against a given external static pressure. The pulley
settings and static pressure values should be predetermined by the system designer. Figure 6-31
shows fan performance tables typical of those included in manufacturer’s installation literature
and an example of their use.
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
References
Section Topics
▼ Figure 6-31.
Example of How Fan Data is Used to Determine Required Fan RPM and Related Motor Pulley Setting
EXAMPLE:
DESIGNER SAYS THE SYSTEM FAN MUST PROVIDE AN AIRFLOW OF 1900 CFM AT AN EXTERNAL STATIC PRESSURE OF 0.4 IN. W.G.
TABLE 1 SHOWS THAT THE FAN MUST ROTATE AT 928 RPM TO DELIVER 1900 CFM. TABLE 2 SHOWS THAT BY OPENING THE MOTOR
PULLEY 3 TURNS, THE FAN WILL ROTATE AT 930 RPM.
TABLE 1 – FAN PERFORMANCE, MODEL 005 VERTICAL DISCHARGE UNITS; ALTERNATE MOTOR (BELT)
AIRFLOW
(CFM)
1200
1300
1400
1500
1600
1700
1800
1900
2000
EXTERNAL STATIC PRESSURE (IN. WG)
0.1
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP
542
576
610
646
681
718
754
791
828
0.16
0.20
0.24
0.28
0.33
0.39
0.45
0.52
0.60
616
644
673
704
735
768
801
836
870
0.21
0.25
0.30
0.35
0.40
0.46
0.53
0.60
0.68
739
764
791
818
845
873
900
928
958
0.32
842 0.44
929
0.56 1008 0.67 1096 0.78
0.37
867 0.50
952
0.62 1029 0.75 1101 0.86
0.42
889 0.55
976
0.69 1052 0.83 1121 0.96
0.48 912 0.61 1001 0.76 1076 0.91
1145 1.06
0.54 938 0.68 1023 0.83 1100 1.00
1168 1.15
0.61 965 0.76 1045 0.91 1124 1.09
1192 1.25
0.69 992 0.84 1071 1.00
1147 1.18
1217 1.36
0.77 1019 0.93 1097 1.10
1169 1.27
1240 1.47
0.86 1046 1.03 1124 1.21
1194 1.38 1262 1.58
–
1184
1189
1208
1232
1255
1279
1303
1327
–
0.99
1.09
1.20
1.31
1.42
1.54
1.66
1.78
–
1299
1265
1271
1291
1314
1338
1361
1385
–
1.15
1.22
1.33
1.46
1.58
1.71
1.85
1.98
–
–
–
–
1364 1.38
1341 1.47
1350 1.60
1370 1.74
1393 1.89
1417 2.03
1440 2.18
Legend
Bhp – Brake Horsepower
NOTES:
1. Boldface indicates field-supplied drive required. (See Note 6)
2. Shading indicates field-supplied motor and drive required.
3. Maximum usable bhp is 1.3. Extensive motor and electrical testing on these units ensures that the full horsepower range of the motor can be
utilized with confidence. Using your fan motors up to the horsepower ratings shown will not result in nuisance tripping or premature motor
failure. Unit warranty will not be affected.
4. Values include losses for the filters, unit casing, and wet coils.
5. Use of a field-supplied motor may affect wire sizing. Contact your distributor to verify.
6. Alternate motor drive range: 800 to 1130 rpm. All other rpm’s require field-supplied drive.
TABLE 2 – FAN RPM AT MOTOR PULLEY SETTINGS
MODEL
MOTOR/DRIVE
005
ALT
STD
ALT
STD
ALT
006
007
0
1/2
1130
1190
1260
1260
1460
1095
1160
1230
1230
1420
1
1060
1130
1195
1195
1380
11/2
1030
1100
1160
1160
1340
MOTOR PULLEY TURNS OPEN
2
21/2
3
31/2
995
1065
1130
1130
1300
960
1035
1100
1100
1265
930
1005
1065
1065
1230
900
970
1030
1030
1190
41/2
4
860
940
995
995
1150
830
910
960
960
1110
5
800
875
930
930
1070
QUICK NOTE
Remember, for a direct-drive motor, speed is adjusted by changing the speed taps.
For a belt-drive motor, speed is adjusted by adjusting the width of the pulley V-groove, which changes
the pulley’s diameter.
BALANCING THE AIR SYSTEM
Air balancing is necessary to make sure that the right amount of air at the right temperature is
delivered to each room in the building. Air distribution systems can be balanced using several
methods; some are complex and others relatively simple. Methods used for balancing air systems are described in several publications listed in the catalog referenced in the front of this
manual. Information is also available in SMACNA’s HVAC Systems Testing, Adjusting, and Balancing manual. A method often used for balancing single-zone residential systems using
thermometers is given here. The procedure presumes that the heating and/or cooling equipment
has been checked out and adjusted per the installation checklist and is operational.
FORCED-AIR DUCT SYSTEMS 6
Table of Contents
Map
Section Topics
References
Thermometer Balancing for
Heating
1. Place a thermometer (Figure 6-32) at the ▼ Figure 6-32.
Typical Thermometers Used for Balancing
center of each room, about four feet above
Air Systems
the floor.
2. Fully open all the diffusers and return grilles.
Set the diffuser vanes for optimum distribution.
3. Set the volume dampers in the branch ducts
INDOOR
farthest from the fan to fully open and the
others to the mid-position.
TEMPERATURE
HUMIDITY
4. Adjust the room thermostat to call for heating (about 2° F above room temperature).
MIN
MAX
RESET
MIN
MAX
Balancing is best done when the temperature in the room is within 5° F of the normal
operating temperature.
5. Operate the system long enough for the room
temperatures to stabilize, then read and
record the temperature in each room.
6. Adjust the volume damper in the branch supplying the warmest room to reduce the airflow to
that room. Do not reduce the airflow too much because the airflow and temperature in the
remaining rooms will increase. Several adjustments to each damper are required.
7. Adjust the remaining dampers. Work from the warmer rooms to the cooler rooms.
8. Repeat the balancing process until the temperature in all rooms is as near to comfort conditions as possible.
9. After balancing is completed, recheck the temperature rise across the furnace heat exchanger
or fan coil electric heating element per the manufacturer’s instructions to make sure that it still
meets specifications. If a blower speed adjustment is needed due to excess temperature rise,
repeat the balancing procedure.
Thermometer Balancing for
Cooling
1. Place a thermometer (Figure 6-32) at the center of each room, about four feet above the floor.
2. Fully open all the diffusers and return grilles. Set the diffuser vanes for optimum distribution.
3. Set the volume dampers in all branch ducts to the mid-position.
4. Adjust the room thermostat to call for cooling and allow the system to operate until the room
temperatures stabilize.
5. Make sure that the system fan is delivering the volume of air specified by the equipment manufacturer. Typically this is between 400 CFM to 450 CFM per ton of cooling. The temperature
drop across the indoor coil should be between 15° F and 20° F.
6. Read and record the temperature in each room.
7. Slightly open the volume dampers in the branches to the rooms with temperatures higher than
the thermostat setting. Slightly close the dampers in the branches to the rooms with temperatures below the design or thermostat setting.
8. Repeat Step 7 as often as necessary to provide even temperatures (±2° F) among the rooms.
9. After balancing is completed, recheck that the fan is delivering the proper volume of airflow per
the manufacturer’s specifications. If a blower speed adjustment is needed, repeat the balancing procedure.
FIELD WIRING
7
▼ FIELD WIRINGG
SECTION 7
INTRODUCTION
Electrical wiring needed to supply power and control signals to HVAC equipment must be installed at the job site and must meet national and local codes. In all cases, the National Electrical
Code® (NEC®) is the primary code for installing wiring in the United States, but wiring must also
meet any other local building code and/or electrical code standards. This section is not intended
to teach circuit design; instead, it describes the various electrical components and wiring methods needed to field wire HVAC equipment. It presumes that the proper type of equipment has
been selected and purchased for the job by a qualified engineer or salesperson based on a
survey of the job. Even though the field wiring is normally installed by electricians, familiarity with
the electrical equipment and wiring methods is important because the HVAC technician normally
is responsible for evaluating the electrical installation to make sure that it complies with the HVAC
equipment manufacturer’s installation instructions.
FIELD WIRING MENU
Typical Building Electrical Service
HVAC Equipment Branch Circuit Components
Circuit Breakers and Fuses
Disconnect / Safety Switches
Wires, Cables, and Connectors
HVAC Thermostat Control Circuit Components
Thermostats
Thermostat Wire
HVAC Unit Electrical Installation Guidelines
Sequence and Use of Installation Instructions
Installing Cable Runs
Installing Conduit Runs
Installing Wires in Wall Partitions
FIELD WIRING
Table of Contents
Map
7
References
Section Topics
TYPICAL BUILDING
ELECTRICAL SERVICE
Power enters a building from the electric utility
power lines through an electrical service. The
most common service used for residential and
light commercial buildings in North America is
120/240-volt single-phase service. Some light
commercial buildings with higher power demands may have a three-phase service. The
focus of this section is on the methods used to
field wire equipment that requires a 120/240volt, single-phase service. When relevant,
methods used to field wire three-phase equipment are also described.
As shown in Figure 7-1, the 120/240-volt
single-phase service applied from the utility pole
transformer to the building has three wires. Two
wires are hot while the third wire is neutral (N).
The voltage across both hot wires is 240 volts;
the voltage across either hot wire and the neutral is 120 volts. The neutral wire is electrically
grounded at the pole power transformer and is
connected to the building ground (earth) either
through a grounding wire between the neutral
bus bar in the service entrance panel and the
building’s cold water piping or a copper rod
driven into the ground.
The entrance panels used in buildings all
operate basically the same. They provide for
the control and distribution of the 120/240-volt
service input power to the individual branch circuits. Most panels use circuit breakers for this
purpose with a main circuit breaker used to disconnect or turn off all power to the building
(Figure 7-2). Some panels may have a removable fuse block to disconnect all power. Some
buildings have a separate disconnect switch
placed ahead of the service entrance panel to
turn off power.
Figure 7-2 shows the components and wiring within a typical service panel. When the
main circuit breaker is set to ON, 120-volt power
is applied through the breaker to the two power
bus bars that run through the panel. Power is
then distributed from the two hot bus bars
through circuit breakers that feed the branch
circuits for the building’s HVAC equipment and
other loads.
The wiring and components used in a
building’s electrical service must have the electrical capacity (ampacity) to adequately carry
all the electrical loads in the building, including
the HVAC equipment. Normally, the adequacy
of the electrical service has been determined
ahead of time. If needed, Article 220 of the
NEC® provides guidelines for determining the
adequacy of a service.
▼ Figure 7-1.
Typical 120/240-Volt Service
SERVICE
HEAD
120/240VOLT POWER
SERVICE
HEAD
NEUTRAL
120V
HOT
UTILITY
STEP-DOWN
TRANSFORMER
240V
ELECTRIC
METER
SERVICE ENTRANCE
PANEL
MAIN DISCONNECT
GROUND CONDUCTOR TO EARTH
VIA WATER PIPES, GROUND ROD, ETC.
▼ Figure 7-2.
Typical Service Entrance Panel
240-VOLT
HOT WIRES
MAIN CIRCUIT
BREAKER
NEUTRAL
WIRE
NEUTRAL
BUS BAR
120-VOLT
SINGLE-POLE
CIRCUIT
BREAKER
HOT BUS BARS
240-VOLT
DOUBLE-POLE
CIRCUIT
BREAKER
BONDING GROUND
SCREW BUS BAR
GROUNDING
WIRE TO
COLD WATER
PIPE/GROUND
ROD
QUICK NOTE
Only qualified electricians may install service entrance equipment and connect the wiring for new
branch circuits in existing panels. However, as part of the installation checkout, the HVAC technician
must verify the correct wiring of branch circuits feeding the installed HVAC equipment. To accomplish
this, the technician must understand how service panels are installed and how they operate in
relation to the entire building electrical system.
FIELD WIRING
Table of Contents
Map
References
Section Topics
HVAC EQUIPMENT BRANCH
CIRCUIT COMPONENTS
Condensing units, furnaces, and packaged
units are completely wired internally at the factory. Wiring referred to as field wiring in
equipment installation instructions must be installed at the job site to connect the power
supply voltages and control voltages to the
equipment. This wiring must always be done in
compliance with national and local codes. It also
must be installed according to the
manufacturer’s installation instructions.
Electrical codes require that the input power
to HVAC equipment be supplied by a separate
branch circuit dedicated to the equipment. With
most equipment, the codes also require that a
safety/disconnect switch be installed on or
within sight of the equipment. This provides the
technician with a safe and convenient way of
turning off power for servicing or repair.
Figure 7-3 shows the components used to
field wire a typical residential split air conditioning system. The methods for field wiring the
power supply voltages are covered here while
thermostats and control wiring are covered later
in this section. The components commonly
used in HVAC equipment power supply wiring
are:
• Circuit breakers and fuses
• Safety/disconnect switches
• Wiring
▼ Figure 7-3.
Typical HVAC Equipment Field Wiring
CONDENSING
UNIT
150-AMP
SERVICE ENTRANCE
240-VOLT
CIRCUIT
DOUBLEPOLE
35-AMP
BREAKER
SAFETY
DISCONNECT
GROUND
ONE 120-VOLT
15-AMP CIRCUIT
BREAKER
CIRCUIT
BREAKER
PANEL
Circuit Breakers and Fuses
Circuit breakers are used in service entrance
panels and subpanels to manually turn on or
off power to a specified circuit. They also protect the circuit from current overloads or short
circuits. In the event of an overload or short
circuit, the breaker automatically “trips” and
opens the circuit. Once tripped, and after the
cause of the problem has been corrected, it can
be reset to restore power to the circuit. This is
normally done by first setting the breaker handle
to the full OFF position, then switching back to
the full ON position.
Breakers can be single-pole for 120-volt circuits or double-pole (two-pole) to protect
240-volt circuits (Figure 7-4). Three-pole breakers are used in three-phase systems. The term
pole refers to the number of conductors (wires)
that the device will control. For example, a
single-pole breaker will control one wire. The
voltage and current rating of a circuit breaker
must be matched to the electrical system in
which it is used. The method used to size circuit breakers and the general procedure for
installing them are covered later in this section.
HACR-type circuit breakers should be used
in circuits connected to compressor units.
HACR breakers have a built-in time delay that
allows a higher current than its rating to momentarily flow in the circuit. This compensates
for the large starting current drawn by a compressor motor.
7
SAFETY
FURNACE
DISCONNECT
▼ Figure 7-4.
Typical Circuit Breakers
ON
AMPERE
RATING
ON
ON
20
20
OFF
ON
20
20
OFF
OFF
OFF
1-POLE
3-POLE
ON
ON
20
OFF
20
OFF
PUS
H
TO
RES
ET
2-POLE
1-POLE GFCI
FIELD WIRING
Table of Contents
Map
References
Section Topics
Another type of special circuit breaker commonly used in entrance panels is the ground
fault circuit interrupter (GFCI). It provides the
normal overcurrent protection of a standard circuit breaker, but also protects people from
electrical shock. Electrical codes define the areas where GFCI breakers or other devices are
required.
Fuses are also used to protect a circuit from
a current overload and are found in service entrance panels or in fused safety/disconnect
switches. There are two main types of fuses:
cartridge and plug (Figure 7-5). Both types
come in different styles and sizes and in instantaneous blow or time delay types.
The ampere rating of each fuse must be
matched to the circuit it protects. Fuses contain an element that melts or “blows” when its
rated amperage is exceeded. Blown fuses must
always be replaced with ones of the same rating and type. Never replace a fuse with one
of a higher rating.
Cartridge fuses are plugged into fuse blocks
in service panels and disconnect/safety
switches. Cartridge fuses can be non-renewable or renewable. Non-renewable fuses are
disposable and must be replaced when blown.
Renewable fuses have elements (links) that can
be replaced.
To determine if a fuse is good or bad (blown),
use a multi-meter to perform a continuity check
or voltage check across the fuse.
Plug-type fuses are made with ratings up to
30 amperes. They are commonly used in fieldwired utility-box disconnects for fossil fuel
furnaces (Figure 7-6). Only S-type plug fuses
(fusestats) and adapter sockets are used. Plug
fuses can be checked visually by looking into
their “window” to see the condition of the fusible link. If the element is broken and/or the
window is black or discolored, the fuse has
blown and must be replaced.
7
▼ Figure 7-5.
Plug and Cartridge Fuses
FUSE ADAPTER
MAXIMUM RATING 30 AMPERES
TYPE-S PLUG FUSE
KNIFE-BLADE WITH
RENEWABLE FUSE
LINKS
➧ CAUTION
FERRULE-END
WITH NONRENEWABLE LINK
CARTRIDGE FUSES
QUICK NOTE
• Before installing a circuit breaker,
make sure it is physically compatible
with the panel in which it will be
installed.
• If there are no vacant slots available
in a panel, additional room can be
made by replacing existing standardsize breakers with slimline-style
▼ Figure 7-6.
Box Cover Unit for Plug Fuse Disconnect
PLUG FUSE
SINGLE-POLE
TOGGLE SWITCH
FIELD WIRING
Table of Contents
Map
References
Section Topics
Disconnect/Safety Switches
Per the electrical code, all fixed HVAC equipment must have a means of disconnecting the
power from the equipment. Disconnect/safety
switches (Figure 7-7) used for this purpose can
be mounted in a metal or plastic indoor or outdoor (weatherproof) enclosure. Disconnect
switches will have a current rating while
switches for use in motor circuits have both
current and horsepower ratings.
Disconnect switches are either non-fusible
or fusible. If the only purpose served by the
switch is to turn the power off and on to the
equipment, a non-fusible switch is used. If the
HVAC equipment manufacturer specifies it, a
fusible disconnect (safety) switch with the
proper size fuse is used.
Disconnects like those shown in Figure 7-7
are operated using an ON-OFF handle. As
shown, when the door is open, the switch
blades and/or fuses are fully visible and
accessible. After the disconnect has been
turned off, the cartridge fuses can be removed
or installed using an insulated fuse puller.
EVEN THOUGH THE DISCONNECT SWITCH
HANDLE IS IN THE OFF POSITION AND THE
FUSES HAVE BEEN REMOVED, THE LINESIDE WIRES AND SWITCH CONTACTS MAY
STILL BE HOT (ENERGIZED) IF THE INCOMING FEEDER POWER HAS NOT BEEN
TURNED OFF. The type of disconnect shown
in Figure 7-8 has a bracket that is used to padlock the switch in the OFF position while
servicing the equipment.
A disconnect commonly called a puller is often used to remove power from HVAC
equipment (Figure 7-9). In this type, the switch
contacts and/or fuses are enclosed in a removable block that fits into a socket within the
disconnect. Power is disconnected by pulling
out the block. Power is restored when the block
is inserted back into the socket.
The size and type of disconnect needed for
use with equipment normally is specified in the
HVAC equipment manufacturer’s installation
instructions. This is covered in more detail later
in this section.
7
▼ Figure 7-7.
Typical General-Purpose Disconnect Switches
ON
OPERATING
HANDLE
OFF
FEEDER WIRES
FROM SERVICE
PANEL
LINE SIDE
OF SWITCH*
CARTRIDGE
FUSE
LOAD SIDE
OF SWITCH
WIRES TO
EQUIPMENT
USE INSULATED
FUSE PULLER TO
REMOVE AND
INSTALL FUSES
* THIS SIDE REMAINS “HOT” WHEN DISCONNECT IS
TURNED OFF OR FUSES ARE PULLED.
➧ WARNING
▼ Figure 7-8.
Disconnect Switch Locked in the OFF Position
DANGER
▼ Figure 7-9.
Typical Air Conditioner Disconnect
COVER
PULL OUT
TO DISCONNECT
POWER AND/OR
ACCESS FUSES
FIELD WIRING
Table of Contents
Map
References
Section Topics
Wires, Cables, and Connectors
Using the correct size wire ensures that it has
the current capacity (ampacity) needed to safely
carry the equipment load. It also prevents excessive voltage drop from occurring in the circuit
that can result in poor operation or damage to
the equipment. To ensure proper operation of
their equipment, HVAC equipment manufacturers include recommendations in their product
literature about the minimum size wire and
maximum length of wire run to use with their
equipment.
The American Wire Gauge (AWG) is the standard used to express wire size or gauge. The
lower the AWG number, the bigger the wire diameter and ampacity. (See Table 7-1.) When
wiring equipment, always use the type of wire
recommended by the equipment manufacturer.
Nonmetallic Sheathed Cable – Nonmetallic
sheathed cable, commonly called Romex®
cable, is used for most of the wiring in residential and light commercial buildings. The outer
sheath of the cable is marked to show the wire
size, number of wires, cable type, and voltage
rating (Figure 7-10). NM-B or NMC-B cable is
used for indoor wiring only, with NM-B cable
being used only in dry areas and NMC-B cable
used in both damp and dry areas. UF-B cable
can be used anywhere that NM-B or NMC-B is
used. It also can be used in wet locations, including underground.
Cutting and Stripping Nonmetallic Cable –
Lineman’s pliers (Figure 7-11) are normally
used to cut nonmetallic cable to length. Then,
the outer sheath at the end is removed using a
knife or a special cable stripper commonly
called a ripper (Figure 7-11). For connections
in boxes, etc. enough sheath should be removed to allow the wires to extend about 8
inches from the front of the box with at least 1/
4 to 1/2 inch of the sheathing showing in the
box above the cable clamp. For connections in
service panels, disconnects, etc. the exposed
wires must be long enough to reach the farthest connection with enough slack to avoid
sharp bends and provide for a neat installation.
The individual wires within the cable can be
stripped using a variety of stripping tools. A
multi-purpose tool is shown in Figure 7-11.
7
▼ Table 7-1.
Maximum Allowable Ampacities of Common
Copper Conductors Used in Residential Wiring
(Maximum of Three Current-Carrying Wires in a
Conduit or Cable)
Type
Wire Size
TW, UF
THW, THWN
THHN
14
15*
15*
15*
12
20*
20*
20*
10
30
30*
30*
8
40
50
55
6
40
50
55
* Unless otherwise permitted by the code, the overcurrent protection for
wire sizes marked with an (*) shall not exceed the amperage shown.
The actual ampacities of the wires are greater. For detailed
information pertaining to all conductors used for general wiring, refer
to the applicable electrical code(s).
▼ Figure 7-10.
Nonmetallic Sheathed Cable
WIRE
SIZE
WHITE
NUMBER OF
CONDUCTORS
CABLE
TYPE
12-2 WITH GROUND TYPE NM-B 600V (UL)
GROUND
WIRE
BLACK
INCLUDES
GROUNDING
WIRE
PLASTIC
SHEATH
▼ Figure 7-11.
Cutting and Stripping Nonmetallic Cable
L R IP
PUL
LINEMAN'S PLIERS
RIPPER TOOL
CUTS SHEATH
WHEN PRESSED
INTO CABLE
REMOVING SHEATH
MULTI-PURPOSE
TOOL
ROTATE TO
CUT INSULATION
PUSH TO
REMOVE
INSULATION
STRIPPING WIRES
PER
FIELD WIRING
Table of Contents
Map
7
References
Section Topics
QUICK NOTE
The wire insulation in a cable or conduit is normally color coded to identify the wire’s intended use:
• Ungrounded “hot” conductors (recommended colors) – Black, red, blue, and yellow. Be aware
that the code permits hot conductors to be any color other than the colors required for use with
neutral or ground wires.
• Neutral (grounded conductors, AWG sizes No. 6 and above) – Required to be white or gray. Note
that white or gray wires can be used as a hot wire if permanently reidentified.
• Grounding conductors – Bare, green, or green with yellow stripe.
Fastening Nonmetallic Cable to Electrical
Boxes – Nonmetallic cable is usually fastened
to HVAC equipment or disconnects using cable
connectors (Figure 7-12). Cable connectors are
installed in a round knockout hole in the HVAC
equipment or disconnect. The knockout is removed by breaking and twisting it loose. After
the knockout is removed, the connector is inserted and the locknut is screwed on and
tightened. The cable is pulled through the connector into the box, then the screws on the
connector are tightened to secure the cable.
Connecting Nonmetallic Cable Grounding
Wires – When fastening nonmetallic cable to
metal boxes, all the cable ground wires must
be connected to each other. Grounding lugs are
provided in most HVAC equipment and disconnects (Figure 7-13).
Armored Cable – Armored (AC) cable, also
called BX, has a flexible steel metal (armor)
sheath that encloses the insulated wires and a
bonding strip and is always used with metal
electrical boxes. It is used for indoor wiring only
in dry locations where it is not subject to physical damage. Guidelines for preparing armored
cable for use once the cable runs are installed
are covered here.
Cutting Armored Cable and Removing the Armor Sheath – Armored cable is usually cut to
length using cable cutters or a hacksaw. The
hacksaw method is described here.
1. Determine where the cable is to be cut.
2. Partially saw through the armor covering
(Figure 7-14), being careful not to cut completely through the armor because this can
damage the conductors and cut the bonding
strip.
3. Bend the cable back and forth at the cut until
the armor breaks. Remove and cut off the
paper that surrounds the wires.
4. Always install an anti-short bushing between
the cut edge of the armor shield and the wires
and bonding strip.
▼ Figure 7-12.
Fastening Nonmetallic Cable to Boxes
KNOCKOUT
1/4" TO 1/2"
SHEATH ABOVE
CONNECTOR
LOCKNUT
TIGHTEN TO SECURE
CABLE IN CONNECTOR
CABLE
▼ Figure 7-13.
Method for Grounding Nonmetallic Cable to Metal
Boxes
CABLE OR
DEVICE GROUND
WIRES
TORQUE AS
REQUIRED
PIGTAIL
GROUND LUG
GROUND CLIP
TYPICAL HVAC
EQUIPMENT GROUNDING
TYPICAL METAL
JUNCTION BOX GROUNDS
▼ Figure 7-14.
Removing Armor Sheath from Armored Cable
PARTIALLY CUT ARMOR SHEATH
FLEX CABLE AND REMOVE ARMOR
SEPARATE WIRES AND INSTALL ANTI-SHORT BUSHING
FIELD WIRING
Table of Contents
Map
References
Section Topics
Fastening Armored Cable to Electrical Boxes
– Armored cable is fastened to metal electrical
boxes with either connectors or built-in clamps
(Figure 7-15). To use an armored cable connector, bend the bonding strip back over the
armor and anti-short bushing. Loosen the connector screw, then slide the connector over the
wires and onto the cable armor until fully seated.
Wrap the bonding strip around the connector
screw and tighten the screw to fasten the connector to the cable. Install the cable with
connector in the box knockout hole and fasten
with the connector locknut.
When fastening armored cable to boxes with
built-in clamps, wrap the bonding strip around
the cable armor and push the cable into the
box pryout hole until the anti-short bushing contacts the face of the clamp, then tighten the
clamp screw to fasten the cable.
Rigid Metallic Conduit – Electrical wires that
run in exposed areas must be protected by rigid
tubing called conduit. Conduit is made in a variety of sizes and the size used is determined
by the number and size of the wire that the conduit must carry. Normally, the size of the conduit
will already have been determined for you. If
needed, refer to the national codes. Most HVAC
installations involve the use of either intermediate metal conduit (IMC) or electrical metal
tubing (EMT), so the remainder of this section
will focus on these types of conduit.
Intermediate Metal Conduit/Electrical Metal
Tubing – IMC conduit (Figure 7-16) can be used
in exposed areas both indoors and outdoors.
IMC is joined together and fastened to boxes
with waterproof compression-type couplings
and fittings. Waterproof L-body fittings with removable covers are used in IMC conduit runs
where the wires must make abrupt bends and/
or when needed to pull long lengths of wire.
EMT conduit (Figure 7-17), commonly called
thin-wall conduit, is used indoors only in areas
where it cannot be damaged. EMT is normally
joined together and fastened to boxes with setscrew-type couplings and fittings. Elbow fittings
with removable covers are also used in EMT
runs where the wires must make abrupt bends
and/or when needed to pull long lengths of wire.
7
▼ Figure 7-15.
Fastening Armored Cable to Boxes
BONDING
STRIP
SETSCREW
BOX
CLAMP
LOCKNUT
QUICK NOTE
An alternate method of cutting armored
cable uses metal shears. Bend the
cable sharply and twist until the armor
buckles. Insert the shears through the
open loop of the buckled sheath and
cut. Trim off any sharp edges.
▼ Figure 7-16.
Intermediate Metal Conduit Coupling, Connector,
and Fittings
LOCKNUT
COMPRESSION NUTS
CONNECTOR
COUPLING
CONDUIT L-BODY, GASKET, AND COVER
▼ Figure 7-17.
Electrical Metal Tubing Coupling, Connector, and
Fittings
SETSCREWS
COUPLING
CONNECTOR
90-DEGREE
CONNECTOR
FIELD WIRING
Table of Contents
Map
References
Section Topics
Cutting, Joining, and Fastening IMC/EMT to
Electrical Boxes and Fittings – Both IMC and
EMT can be cut with a hacksaw. After making
the cut, the inside edge of the conduit or tubing
must be reamed to remove burrs which might
damage the wires.
To join straight sections of IMC together, the
ends are inserted into the coupling and the compression nuts are tightened. Connecting IMC
to a box with a connector is done in a similar
manner. After this, the locknut is removed and
the connector with attached conduit is inserted
into the knockout hole. The locknut is then used
to secure the conduit to the box.
Joining sections of EMT and/or connecting it
to electrical boxes is done in the same way as
with IMC, except that the coupling or connector setscrews are used to tighten the coupling
or connector to the tubing.
Bending IMC/EMT Conduit – Conduit can be
bent (Figure 7-18) into angles using a bender
called a hickey. This is done by placing the
bender on the conduit so that its hook is where
you want the bend to start. The conduit is bent
by stepping on the bender tread to hold the conduit and bender in place, then pulling the bender
handle back until the conduit is bent to the required angle. Some benders have a built-in
bubble level or markings to indicate when 45°
and 90° bends have been made. Because
bending to precise measurements is difficult, it
is recommended that the conduit be bent first
and then cut to the exact length needed.
Rigid Nonmetallic (PVC) Conduit – Rigid nonmetallic (PVC) conduit and fittings are also
available. They resemble those used with metal
conduit. Conduit sections are assembled and
joined to PVC electrical boxes using solventbased cement.
▼ Figure 7-18.
Bending Conduit
HANDLE
DESIRED
START OF
BEND
HICKEY
TREAD
▼ Figure 7-19.
Connecting Wires to Fish Tape
Pulling Wires/Cables through Conduit Runs –
For other than very short runs, a flexible steel
fish tape (Figure 7-19) is used to pull the wires
through the conduit. The fish tape is pushed
through the run first, then the ends of the wires
are securely fastened to the end of the tape.
The tape is then pulled back through, pulling
the wires with it. The wires should be kept as
straight as possible to prevent them from becoming tangled or crossed. To make pulling the
wires easier, they can be coated with a special
lubricant. Sometimes a second person is helpful when pulling wires.
Flexible Conduit – Flexible conduit is often
used with outdoor wiring of air conditioning
equipment. Liquidtight flexible metal conduit
and liquidtight flexible nonmetallic conduit are
more commonly used with HVAC equipment.
The body of liquidtight flexible conduit is made
with spiral metal turns which are covered with
a weatherproof plastic. Special connectors and
methods are used to install both the metal and
nonmetallic types. For this reason, factory-wired
assemblies called air conditioner whips
(Figure 7-20), available in various lengths, are
often purchased and used to simplify an
installation.
7
▼ Figure 7-20.
Preassembled Liquidtight Air Conditioner Whip
FIELD WIRING
Table of Contents
Map
References
Section Topics
Wire Connectors/Terminals – To complete the
field wiring of a circuit, the wires must be joined
together or connected to terminals. Unless otherwise marked on the equipment, aluminum
wire cannot be used to supply power to HVAC
equipment. Always refer to the equipment or
component manufacturer’s installation instructions for information concerning the types of
wire that can be safely connected to the equipment.
Splicing Wires – Splices made to join wires must
be made inside an electrical box or enclosure
using approved connectors. Most splices are
made using connectors commonly called wire
nuts (Figure 7-21). Wire nut manufacturers color
code the wire nuts and mark their packages to
show the wire sizes and the maximum and minimum number of wires that can be connected
by the wire nut. Note that green wire nuts are
only used to splice grounding wires.
To splice wires with a wire nut, first strip off
about 1/2 inch of the insulation. Place the wire
nut over the wire ends, then turn or screw it
onto the wires until the nut is tight. It is a good
practice to twist the wires together before screwing on the wire nut. When the wire nut is fully
tightened, no bare wires should be visible. Insulated crimp-type connectors may also be
used to splice wires. The connector is slipped
over the stripped wire ends, then crimped using a multi-purpose tool.
When No. 6 gauge and larger wires must be
spliced, split-bolt or clamp connectors
(Figure 7-22) are commonly used. With these
connectors, the stripped wire ends are placed
into the body of the connector and the screw or
bolt is tightened to make the splice. The splice
is then wrapped with electrical tape.
Connecting Wires to Terminals – Equipment
connections are often made using compression-type lugs or terminals strips (Figure 7-23).
Normally, only one wire is permitted per terminal and the terminal screw must be torqued to
specifications. For panels, disconnect switches,
etc., the screw torque requirements and number of wires per terminal are normally marked
on the inside of the door. For HVAC equipment,
this information may be marked on the equipment and/or given in the installation instructions.
It is important that the free end of any energized or deenergized wire not connected to a
terminal be covered with insulating tape or a
wire nut. To make connections to screw-type
terminals, loop the wire around the screw post
in a clockwise direction and then tighten the
screw securely.
7
▼ Figure 7-21.
Splicing Wires Using a Wire Nut or Crimp
Connector
CRIMP
CONNECTOR
▼ Figure 7-22.
Splicing Larger Wires Using Clamp and Split-Bolt
Connectors
CLAMP CONNECTOR
SPLIT-BOLT CONNECTOR
▼ Figure 7-23.
Connecting Wires to Compression Terminals
TORQUE AS
REQUIRED
WRONG WAY
RIGHT WAY
DEVICE SCREW
FIELD WIRING
Table of Contents
Map
References
Section Topics
HVAC THERMOSTAT
CONTROL CIRCUIT
COMPONENTS
Control circuit wiring between the heating and/
or cooling equipment and the room thermostat
must be field wired (Figure 7-24). Most control
circuits operate on low voltage (24 volts AC)
derived from a transformer normally located in
the system furnace or fan coil unit.
▼ Figure 7-24.
Typical Low-Voltage Control Wiring
THERMOSTAT
CONDENSING
UNIT
FURNACE
Thermostats
All thermostat and control circuit wiring must
be done in accordance with electrical codes and
the equipment installation instructions. This is
covered in more detail later in this section. Most
manufacturers mark their thermostat terminals
using an HVAC industry standard that identifies the thermostat terminals by function and
the related color of the wires that should be
connected to them. (See Table 7-2.)
SUBBASE
FAN
ON
70 80 9
0
60
60
80
TO
Thermostat Wire
▼ Figure 7-25.
Heating/Cooling System Thermostats
AU
Installing Thermostats – Thermostat installation instructions should always be read
carefully. This is especially important with electronic thermostats, because they require special
handling. Some electronic thermostats may
require the installation of an isolation relay.
Some general guidelines for installing all thermostats are given here.
The thermostat must be installed in the area
it is intended to control, on an inside wall that is
free from any vibration and away from stairways. It should be mounted about 52 inches
above the floor in an area with good air circulation at room temperature. All thermostats should
be leveled for appearance and accurate operation. Locations with the following conditions
should be avoided:
• Drafts or dead air spots
• Hot or cold air from ducts or diffusers
• Radiant heat from sunlight or a fireplace
• Concealed pipes or heating/cooling ducts
• Unheated areas behind the thermostat, such
as an outside wall or garage
LOW-VOLTAGE
CONTROL WIRES
80
70
60
50
70
60
50
9
0
Thermostats turn the applicable heating or cooling unit on or off as needed to maintain the
desired room temperature. Thermostats are
made that can control heating-only, coolingonly, or both heating and cooling (Figure 7-25).
7
70 80
HEATING/COOLING
THERMOSTAT
1
6
HEAT PUMP
THERMOSTAT
2 3
7 8
4
5
9
0
ELECTRONIC PROGRAMMABLE THERMOSTAT
▼ Table 7-2.
Thermostat Wiring Codes
Terminal
Marking
Wire Color
R
Red
G
Green
Fan control
Y
Yellow
Cooling control
Y1 = Stage 1
Y2 = Stage 2
W
White
Heating control
W1 = Stage 1
W2 = Stage 2
O
Orange
Heat pump
reversing valve
control
Function
Power (24 volts)
FIELD WIRING
Map
References
Section Topics
HVAC UNIT ELECTRICAL
INSTALLATION GUIDELINES
Before starting the installation, the HVAC
unit(s), electrical components, wire, and other
materials to be installed should be checked to
make sure that they are of the correct type and
size.
The rating plate (Figure 7-28) attached to
each HVAC unit should be checked to make
sure that the POWER SUPPLY VOLTS listed
are compatible with the voltages supplied by
the building’s electrical service. Also check the
MAX OVERCURRENT PROTECTIVE DEVICE
information shown on the rating plate to make
sure any circuit breakers/fuses and the disconnect are of the proper type and amperage
rating. For air conditioner and heat pump units,
the plate will state either MAX SIZE FUSE or
both MAX SIZE FUSE and MAX HACR CKTBKR (CIRCUIT BREAKER).
When it only states MAX SIZE FUSE, fuses
must be used to protect the unit. Assuming that
a service panel with circuit breakers is being
used to supply power to the unit, this means
that a fused disconnect with the proper size
fuses must be used with the unit. For example,
if the maximum size fuse specified on the rating plate is 30 amps, then the service panel
must use a 30-amp circuit breaker and a fused
disconnect with 30-amp fuses. When the plate
states MAXIMUM SIZE HACR CKT-BKR, an
HACR-type circuit breaker normally is installed
in the service panel and a non-fused disconnect is used with the unit.
▼ Figure 7-26.
Thermostat Wire and Wire Stripper
OSTAT W
RM
E
IR
Thermostats located within 100 feet of the
heating/cooling unit are normally connected
with No. 18 gauge wire. No. 16 gauge wire
should be used if the thermostat is located more
than 100 feet from the unit. Multi-wire thermostat cable typically comes in 250- or 500-foot
spools (Figure 7-26).
To wire a thermostat, identify the terminals
and color codes of the connecting wires as they
relate to the equipment wiring diagram. Strip
the wires with a wire stripper made specifically
for small gauge wires. Make sure that all wires
are connected properly and the connections are
tight. Also, the wire access opening in the wall
space behind the thermostat should be sealed
so that the thermostat is not affected by drafts
within the wall stud space.
The final step is to check the operation of
the thermostat after power is applied. If required, the heat anticipator setting must also
be adjusted per the thermostat’s installation instructions to match the current draw of the
primary control in the heating unit
(Figure 7-27). The current value used for the
adjustment may be stamped on the furnace
nameplate and/or primary control or may have
to be measured. The method for measuring and
adjusting the thermostat heat anticipator current is given in Section 8. The heat anticipator
adjustment determines the duration of the
burner-on cycle.
THE
Table of Contents
7
▼ Figure 7-27.
Adjusting the Thermostat Heat Anticipator
70
80
90
THERMOSTAT
HEAT ANTICIPATOR
24 VAC,
60Hz 0.4A
PRIMARY CONTROL
(GAS VALVE)
CURRENT RATING
▼ Figure 7-28.
Typical Air Conditioning Unit Rating Plate
FIELD WIRING
Table of Contents
Map
References
Section Topics
For the previous example, a 30-amp HACR circuit breaker should be used. The use of a
standard circuit breaker instead of an
HACR-type circuit breaker violates the electrical code.
The value given for MINIMUM CIRCUIT
AMPS (MCA or MCC) is used to determine wire
size. For example, if the value listed is 18.1
amps, then the appropriate table in the electrical code is used to find the wire size needed.
In the United States, NEC® Table 310-16 is normally used (see Table 7-3). For this example,
the table shows that No. 12 gauge wire must
be used.
Note that the ampacity values given in the
table are based on an ambient temperature of
86° F. To determine the correct wire size for
locations with higher ambient temperatures,
such as rooftops, attics, etc., the ampacity listed
for a specific size and type of wire must be derated by multiplying the given ampere value by
a correction factor. For example, when subjected to ambient temperatures ranging
between 114° F and 122° F, the maximum
ampacity of No. 12 TW wire is only 14.5 amps
(25 x .58). To carry the 18.1 amps given for our
example, No. 8 TW wire must be used. When
No. 12 THHN wire is subjected to the same
range of temperatures, its maximum ampacity
is 24.6 amps (30 x .82), allowing it to be used.
Voltage drops exceeding 2% between the
unit and service panel are considered excessive. When installing wiring runs that have
one-way path lengths longer than about 80 feet,
it is recommended that the next larger wire size
be used to avoid possible voltage drop
problems.
Sequence and Use of Installation
Instructions
The general sequence for the electrical installation used with most HVAC units is outlined
below.
1. Study the building’s construction to determine
the best routing for the branch and control
circuit wiring.
2. Install the branch circuit components at their
locations, then run the cable and/or conduit
and wires between these components, the
building’s service panel, and the unit. Refer
to the unit reference drawing in the installation instructions for the location of the unit’s
power wiring access hole.
3. With the exception of the wires in the service panel, connect all branch circuit wiring,
including those in the unit.
7
➧ CAUTION
▼ Table 7-3.
Maximum Ampacities of Common Copper
Conductors – Based on an Ambient Temperature of
86° F (30° C) and with No More than Three
Current-Carrying Wires in a Conduit or Cable
(Based on NEC® Table 310-16)
Type/Temperature Rating
Wire Size
140° F (60° C)
TW, UF
140° F (75° C)
THW, THWN
194° F (90° C)
THHN
14
20*
20*
25*
12
25*
25*
30*
10
30
35*
40*
8
40
50
55
6
55
65
75
Ambient
Temperature
Correction Factors
For ambient temperatures above
86° F (30° C), multiply the ampacities shown
above by the appropriate factor shown below.
87° F - 90° F
.91
.94
.96
96° F - 104° F
.82
.88
.91
105° F - 113° F
.71
.82
.87
114° F - 122° F
.58
.75
.82
* The overcurrent protection for wire sizes marked with an (*) shall not exceed
15 amps for No. 14, 20 amps for No. 12, and 30 amps for No. 10 after any
correction factors for ambient temperature have been applied.
FIELD WIRING
Table of Contents
Map
Section Topics
7
References
For wiring details between the disconnect
and the unit, refer to the wiring diagrams
given in the installation instructions
(Figure 7-29). Also refer to the unit’s component layout diagram for the location of
electrical components within the unit. To
➧ CAUTION
avoid mistakes, always be sure to read
all notes given on these diagrams.
4. Install and connect the control wiring between
the thermostat and the unit(s). Refer to the
unit reference drawing for the location of the
control wiring access hole.
For wiring details between the thermostat
and the unit(s), refer to the connection and
wiring diagrams given in the installation instructions (Figure 7-30).
5. Have a qualified electrician install the circuit breaker(s) and connect the wires for the unit
branch circuit in the service panel/subpanel. Be sure to label the new circuit breaker(s).
For a 120-volt branch circuit, the black wire should be connected to the terminal of a singlepole circuit breaker, and the neutral and ground wires to the neutral and ground bus, respectively.
This presumes the use of a two-wire cable.
For a 240-volt branch circuit, the black and white wires should be connected to the terminals
of a double-pole circuit breaker and the ground wire to the ground bus. This presumes the use
of a two-wire cable. There is no neutral bus connection. The white wire should be marked with
tape or paint to indicate that it is hot.
6. Check out the unit’s electrical operation per the installation instructions and checklist(s).
▼ Figure 7-29.
Typical Electrical Wiring Data Contained in
Manufacturer’s Equipment Installation Instructions
▼ Figure 7-30.
Typical Control Wiring Data Contained in
Manufacturer’s Equipment Installation Instructions
FIELD WIRING
Table of Contents
Map
Section Topics
7
References
Installing Cable Runs
Nonmetallic Cable – Where nonmetallic cable runs are used in exposed areas such as basements and attics, they should be run along a joist or through drilled holes (Figure 7-31). In attics,
they should also be protected by a running board nailed across the joists over the cable runs.
When run across the top of joists in attics, the cable should be protected on both sides by guard
strips at least as high as the cable. Note that if exposed and passing through a floor, nonmetallic
cable must be protected for at least six inches above the floor with metal conduit that has bushings at both ends. This protects the cables from abrasion.
Holes for cable runs should be drilled in the building framing after all boxes and equipment are
mounted. Holes should be bored in the center of the framing member so that the edges of the
holes are at least 1-1/4 inches from the edge. If this clearance cannot be maintained, the cable
must be protected by a steel nail plate at least 1/16-inch thick. Nail plates must also be used if it
is necessary to run cable in notches cut into studs.
Cable must be fastened within 12 inches of metal boxes and, if not run through drilled holes, at
least every 4-1/2 feet of length. The radius at the inside of any cable bends should not be less
than five times the cable diameter. For example, with 1/2-inch cable, the radius of the bend must
be at least 2-1/2 inches.
Low-Voltage Control Cable – Electrical codes prohibit the running of low-voltage control wiring
inside the same conduit as power cables. This is why HVAC equipment normally has separate
openings (knockouts) for the power and control wiring. Because control voltage is considered
safe from fire hazard, it can be run exposed and need not be installed in conduit; however, it must
be installed in a way that the cables will not be damaged by normal building use. It can be
fastened using tape or wire ties to the outside of the conduit, etc. containing the power wires for
the same equipment (Figure 7-32). When run to outdoor units, the control wiring is frequently run
along with and taped to the refrigerant lines.
▼ Figure 7-31.
Running Nonmetallic Cable
▼ Figure 7-32.
Typical Control Circuit Cable Installation
STRAP OR STAPLE
NONMETALLIC
CABLE
CLASS 2 LOWVOLTAGE CONTROL
CIRCUIT CABLE
TAPED TO CONDUIT
STRAP EVERY
41/2 FEET
HOLES AT LEAST
11/4 INCHES
FROM EDGE
BASEMENT INSTALLATION
GUARD STRIPS
RUNNING
BOARD
THIS CONDUIT
CONTAINS THE
POWER CONDUCTORS
SUPPLYING
THE FURNACE
DISCONNECT
SWITCH
ATTIC INSTALLATION
FIELD WIRING
Table of Contents
Map
References
Section Topics
Installing Conduit Runs
The general methods for installing conduit were
covered earlier in this section. The conduit must
be supported with straps within three feet of
every box and fastened in place at intervals not
exceeding ten feet. Various fittings are available to make the transition from indoor
nonmetallic cable to conduit needed for exposed outdoor wiring. Figure 7-33 shows a
typical method. It also shows a common use of
liquidtight flexible conduit.
Installing Wires in Wall Partitions
When installing systems in existing buildings,
thermostat wires (and sometimes power wiring) must be pulled between different floor
levels and inside finished walls. For thermostat
control wiring, this means that holes must be
drilled through the building’s framing to provide
access for pulling the thermostat wires needed
to connect the thermostat to the unit.
To go from a basement to a wall on the first
floor, drill from the basement up (Figure 7-34).
If drilling from an attic to the floor below, the
method is basically the same, except drill down.
Then, an access hole for the wires is made in
the first floor wall at the thermostat’s mounting
location (Figure 7-35).
A fish tape is pushed up through the hole in
the basement (or down from the attic) above or
below the thermostat’s wire hole in the wall. A
hooked end wire is used to “snag” the fish tape
through the hole in the wall. Once the fish tape
is hooked, it can be pulled out of the thermostat wire hole with three or four feet sticking
out into the room. The thermostat wires are
securely fastened to the hook of the fish tape
and pulled back through the two holes and into
the basement (or attic), where the wires are
run to the unit. Note that the actual method used
to install the fish tape and pull the wires should
be the easiest one that fits the situation. In some
situations, it may be as easy as using an existing thermostat wire to pull the new wire.
7
▼ Figure 7-33.
Typical Method Used to Transition from Indoor to
Outdoor Wiring
BUSHING
CONDUIT
(LB CONNECTOR)
NONMETALLIC
CABLE
CONDUIT
LB
LIQUIDTIGHT
CONNECTOR
FLEXIBLE
DISCONNECT CONDUIT
▼ Figure 7-34.
Drilling Cable Access Holes from Basements and
Attics
BASEBOARD
SOLID
WALL
SOLE PLATE
ATTIC
JOIST
BASEMENT
BASEMENT
SOLID
WALL
ATTIC OR UPPER FLOOR
▼ Figure 7-35.
Example of Running a Fish Tape Between the
Basement and the First Floor
SOLID
WALL
FISH
TAPE
THERMOSTAT
WIRE HOLE
SOLE
PLATE
FISH
TAPE
DRILLED
HOLE
JOISTS
GAS FURNACE INSTALLATION
8
▼GAS FURNACE INSTALLATION
SECTION 8
INTRODUCTION
This section provides guidelines for the installation of gas-fired, forced-air furnaces and their
accessories. It is not intended to teach gas furnace or vent and combustion air theory; instead, it
describes the different kinds of furnaces, the common accessories used with them, and the methods used to install them. This section presumes that the proper type of furnace and related
accessories have been selected and purchased by a qualified engineer or salesperson based on
a survey of the job.
GAS FURNACE MENU
Types of Gas-Fired Furnaces
Natural Draft Furnaces
Induced-Draft Furnaces
Condensing Furnaces
Furnace Configurations
Upflow Furnaces
Downflow Furnaces
Horizontal Furnaces
Multi-Poise Furnaces
Natural Gas and Propane Furnaces
Accessories
Humidifiers
Electronic Air Cleaners
Condensate Pumps
Furnace Vent Systems
Induced-Draft Furnace Vent Systems (Category I Vents)
Condensing Furnace Vent Systems (Category IV Vents)
Furnace Installation Guidelines
Initial Preparation
Removal of an Existing Furnace
Locating the Furnace
Induced-Draft Furnace Combustion and Ventilation
Installing and Leveling the Furnace
Installing the Air Distribution System Ductwork
Installing Gas Piping
Installing Power and Control Wiring
Installing Venting
Installing Condensate Drains
Start-Up and Checkout
Final Checks, Adjustments, and Tasks
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
TYPES OF GAS-FIRED FURNACES
A gas furnace is rated in terms of its annual fuel utilization efficiency (AFUE). This rating, expressed as a percentage, represents the annual average efficiency of the furnace, taking into
account the effect of on-off operation. All furnaces produced after 1992 must have an AFUE
rating of at least 78%. There are three types of furnaces: natural draft, induced draft, and condensing.
Natural-Draft Furnaces
Natural-draft furnaces rely on the buoyancy of the hot combustion products to create the draft
needed to draw combustion products through the heat exchanger and out the vent system. Most
manufacturers no longer produce this type of furnace because it is difficult to obtain a 78% AFUE
with this technology.
Induced-Draft Furnaces
Non-condensing, induced-draft furnaces
(Figure 8-1) typically have AFUE ratings of at
least 78%. They achieve this increased efficiency by using an inducer fan to draw the
combustion products through a more efficient
heat exchanger which transfers more heat from
the combustion products to the conditioned air
passing over the heat exchanger, thus reducing the temperature at which the combustion
products leave the furnace. The inducer fan
also restricts the flow of warm air out of the vent
during the off cycle. Venting of induced-draft,
non-condensing furnaces is covered in more
detail later in this section.
▼ Figure 8-1.
Induced-Draft Furnace
FLUE GAS
INDUCER
FAN
HEAT
EXCHANGER
COMBUSTION
AIR
AFUE 78% – 89%
Condensing Furnaces
Condensing furnaces (Figure 8-2) have the
highest efficiencies, with AFUE ratings above
90%. They achieve this by using an additional
heat exchanger which removes latent heat from
the flue gases by condensing the water vapor.
Condensing furnaces use a more powerful inducer fan than induced-draft furnaces because
of the added pressure drop of the condensing
heat exchanger and the need to move combustion air and combustion products through
long runs of pipe. Condensing furnaces do not
exhaust flue gases into a vent system like those
used with non-condensing furnaces. Instead,
condensing furnaces may use 100% outdoor
air for combustion. This air is obtained through
a sealed combustion air/vent system powered
by the inducer fan. The combustion products
are discharged from the building through the
exhaust vent by the inducer fan. The combustion air and venting systems used with
condensing furnaces are covered in more detail later in this section. The condensate
produced in the condensing heat exchanger
must be disposed of properly.
▼ Figure 8-2.
Condensing Furnace
COMBUSTION
AIR
HEAT
EXCHANGER
FLUE
GAS
CONDENSING
HEAT
EXCHANGER
AFUE >90%
GAS FURNACE INSTALLATION
Table of Contents
Map
References
Section Topics
FURNACE CONFIGURATIONS
Depending on the building structure and application, four basic configurations of induced-draft
or condensing furnaces are used to cover most
applications: upflow, downflow, horizontal, and
multi-poise.
▼ Figure 8-3.
Typical Induced-Draft Furnace; Basement Upflow
Installation
Upflow Furnaces
The upflow furnace (Figure 8-3) is the most
widely used, and is generally installed in basements, closets, or equipment rooms. Return
air via the return duct system enters the lower
side or bottom of the furnace through an air
filter or electronic air cleaner (EAC), is pushed
through the heat exchanger by the blower, then
is discharged through the supply air duct system. When used with central air conditioning,
the cooling coil is located in the supply air plenum.
Downflow Furnaces
The downflow or counterflow furnace
(Figure 8-4) is the opposite of the upflow furnace. Return air enters the top of the furnace
through the air filter or EAC and is pushed
downward through the heat exchanger by the
blower. It is then discharged into the supply air
duct system located below the furnace. This
type of furnace is often used in buildings that
are built with a crawlspace or on a slab. When
used with a central air conditioning system, the
cooling coil is mounted under the furnace in the
supply air plenum.
▼ Figure 8-4.
Typical Condensing Furnace; Closet Downflow
Installation
Horizontal Furnaces
The horizontal furnace can be installed on the
floor of an attic (Figure 8-5), suspended from
an attic ceiling, or under the floor in a
crawlspace. Return air is drawn into the blower
and forced horizontally over the heat exchanger
into the duct system. Special horizontal cooling coils are used if air conditioning is installed.
▼ Figure 8-5.
Typical Condensing Furnace; Attic Horizontal
Installation
Multi-Poise Furnaces
Multi-poise (multi-position) furnaces
(Figure 8-6) are versatile furnaces that can be
installed in any position: upflow, downflow, horizontal left, or horizontal right. Usually, they
come shipped from the factory configured for
upflow use, but can be easily converted for
other applications. Keep in mind that it is usually easier to make any conversion at the shop,
instead of at the job site.
8
▼ Figure 8-6.
Multi-Poise Furnace Orientations
AIRFLOW
UPFLOW
HORIZONTAL
LEFT
AIRFLOW
HORIZONTAL
RIGHT
DOWNFLOW
AIRFLOW
AIRFLOW
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
Natural Gas and Propane Gas Furnaces
Gas furnaces are designed to burn natural gas or propane gas. Both gases are safe if the furnace
is installed correctly and proper safety measures are used. However, both gases are explosive if
allowed to leak or are mishandled.
Natural Gas – Most gas-fired furnaces use natural gas. Natural gas is lighter than air and will rise
and diffuse into the surrounding air should a leak occur. It can displace the oxygen in the air and
can be explosive. Natural gas has an odorant added to alert people to any leaks.
Propane Gas – Propane gas is typically used
in rural areas and other places where natural
gas is not available. Propane is a liquified petroleum gas (LPG) that has been compressed
into its liquid form and stored under pressure
in a tank. It can only be used as a fuel when it
is in the vapor state. Refer to Table 8-1 for a
comparison of propane and natural gas characteristics. Propane gas is heavier than air and
will collect and stay in low places if a leak occurs. Propane also has a distinct odor to alert
people to any leaks.
Pressure regulators in the propane gas supply system reduce the pressure of the propane
gas in the storage tank to 11 in. w.c. at the building input for use with furnaces and other
appliances. Propane is an excellent solvent.
Therefore, when assembling propane piping to a furnace always make sure to use a
pipe joint compound that is resistant to LP
gas.
Furnace Conversion Kits – Gas furnaces are
assembled at the factory to burn only one kind
of gas. Do not use propane gas in a natural
gas furnace or vice versa because an unsafe condition will be created. Most
manufacturers make kits to convert the operation of a furnace from one fuel to the other.
These conversion kits should be installed following the instructions supplied with the kits.
Conversion kits are necessary because the
specific gravity of a gas affects its flow through
pipes and a furnace’s gas orifices. Orifices are
located in the gas manifold (Figure 8-7) and
determine how much gas is delivered to a
burner. They are designed and sized for a specific furnace model operating with a specific
gas. The conversion process involves changing the orifices as well as making changes to
the gas valve regulator. Other components may
need to be installed in the furnace electrical circuit to complete the conversion.
▼ Table 8-1.
Propane and Natural Gas Characteristics
Parameter
Natural Gas
Propane Gas
Ignition Temp. (°F)
1,170
932
Cu. ft. air needed
to burn one cu. ft.
gas
10
25
Heating value
Btu's/cu. ft.
1,050
2,500
Specific gravity
0.4 - 0.8
1.5
➧ CAUTION
➧ CAUTION
▼ Figure 8-7.
Gas Manifold
GAS VALVE
REGULATOR
43
SPUD
MANIFOLD
BURNERS
ORIFICE
ORIFICE
SIZE
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
ACCESSORIES
Many furnace jobs require installing additional accessories such as a humidifier, electronic air
cleaner, and/or a condensate pump.
Humidifiers
A humidifier (Figure 8-8) adds water vapor to a
building’s air supply in the winter to provide a
comfortable humidity level. Humidifier operation is controlled by a humidistat which senses
the relative humidity of the air in the home. Fanpowered and bypass humidifiers are the most
commonly used humidifiers with gas furnaces.
These humidifiers depend on the flow of warm
air over a wet media pad to cause the evaporation of water into the airstream.
Fan-powered humidifiers are installed on the
supply plenum. This allows warm air from the
supply airstream to be drawn into the humidifier by the fan, passed through the humidifier’s
wet media pad, then returned to the supply airstream for distribution.
Bypass humidifiers can be installed either on
the supply or return duct, allowing airflow in either direction through the unit. Bypass
humidifiers work because of the air pressure
difference that exists between the supply and
return ductwork. Heated air passes out of the
supply duct, through the humidifier, and then
back into the return air duct via a field-supplied
bypass duct installed between the supply and
return ducts.
Many furnaces have built-in terminals to connect the humidifier to the furnace control circuit.
Normally, the humidifier only operates when
there is a call for heat and the furnace blower
motor is energized.
▼ Figure 8-8.
Fan-Powered and Bypass Humidifiers
QUICK NOTE
LOW HUMIDITY PROBLEMS
• Dry, itchy skin
• Static electricity shocks
• Sinus problems
• Chilly feeling
• Sickly pets
• Sickly plants
• Furniture joints loosen
• Clothing static cling
Electronic Air Cleaners
Electronic air cleaners or EACs (Figure 8-9)
remove dust, pollen, and smoke from the air in
the conditioned space. They have a high-voltage power supply used to charge (ionize),
attract, and collect particles in the air that
passes through the filter. EACs can be installed
with all configurations of furnaces in the furnace
return air connection. Many furnaces have terminals for connecting the EAC. They are wired
into the furnace fan circuit so that they operate
whenever the furnace blower motor is energized, regardless of the operating mode.
▼ Figure 8-9.
Typical Electronic Air Cleaner
GAS FURNACE INSTALLATION
Table of Contents
Map
References
Section Topics
Condensate Pumps
When gravity drains are impractical, condensate pumps (Figure 8-10) are used to pump the
condensate from condensing furnaces and/or
cooling coils or excess water from humidifiers
into a drain. Condensate pumps should be installed as near as possible to the unit being
drained. Pump operation is controlled by a floatoperated switch that senses the water level.
Many pumps have a safety overflow switch to
shut down the related heating or cooling equipment should the condensate pump fail. This
stops the flow of condensate into the pump tank,
where it could overflow and cause water damage.
8
▼ Figure 8-10.
Condensate Pump
OPEN STAND
PIPE FOR AC
AND/OR
HUMIDIFIER
DRAIN
TO
BUILDING
DRAIN
CONDENSATE
TRAP
CONDENSATE
PUMP
FURNACE VENT SYSTEMS
The furnace vent system carries the products of combustion from the furnace to the outdoors.
The type and size of the vent system must be carefully matched to the furnace. Undersized or
oversized vents will result in poor furnace performance and may cause an unsafe condition. The
installation of vent systems must always comply with national and/or local codes and regulations
that govern installations. Category I vents are used with induced-draft and natural-draft furnaces
while Category IV vents are used with condensing furnaces.
Induced-Draft Furnace Vent
Systems (Category I Vents)
Category I vents (Figure 8-11) consist of a
pitched horizontal run from the furnace, called
the vent connector, and the vertical section of
metal pipe or chimney, called the vent, that
moves combustion products outdoors. Often
the furnace is “common-vented” with another
appliance, usually the water heater. Type-B
double-wall metal vent pipe or a lined masonry
chimney must be used as the vent with induceddraft and natural-draft furnaces. Existing metal
vents and chimneys that are in good condition
and properly constructed may be reusable if
they meet the code and size requirements.
They must be replaced or relined if they are
undersized or oversized or not in good condition. Normally, the adequacy of an existing vent
system, or the design of a new one, has been
determined ahead of time. If needed, refer to
the National Fuel Gas Code and the
manufacturer’s instructions for vent sizing
tables (Figure 8-12) and examples of how to
use them to find vent sizes.
▼ Figure 8-11.
Category I Vents Used with Induced-Draft
Furnaces
TILE-LINED
MASONRY
CHIMNEY
TYPE-B
DOUBLE-WALL
VENT
▼ Figure 8-12.
Example of a Typical National Fuel Gas Code
Vent Sizing Table
GAS FURNACE INSTALLATION
Table of Contents
Map
References
Section Topics
General Guidelines for Installing Metal Vents
and Vent Connectors – If installing a metal
vent system, double-wall (Type-B) metal vent
piping (Figure 8-13) must be used as the main
vent with induced-draft or natural-draft furnaces.
Good practice is to also use double-wall pipe
for the vent connector because it has a much
lower heat loss than single-wall pipe and it provides for greater installation flexibility.
Single-wall pipe has a high heat loss that severely limits its use. It can sometimes be used
as a vent connector, but never for the vent itself. The discussion in the remainder of this
section presumes the use of double-wall pipe
for both the vent and vent connector.
Main Vent – The diameter, height, and number
of elbows determine the resistance the vent offers to the flow of flue gases. For this reason,
a straight run to the roof is preferred. Should it
be necessary to offset the upper portion in order to bypass an obstruction, good practice is
to use 45° elbows instead of 90° elbows to keep
restrictions to a minimum (see Figure 8-13).
Fire regulations require that a firestop made
from non-combustible materials be installed
where the vent passes through floors and ceilings.
Always install the vent cap specified by the
vent manufacturer. Use of the wrong cap or
an unapproved cap can adversely affect
venting action. Codes require that a vent (or
chimney) termination project a minimum height
above the roof to prevent wind forces from disturbing the venting action. Consult the
applicable code for the required distances.
Generally, the codes specify:
• For Type-B vents up to 12 inches in diameter with listed caps and located at least eight
feet from a vertical wall, the height varies with
the roof pitch (Figure 8-14).
• For all other vents, the minimum height is
two feet above the highest point where they
pass through the roof and at least two feet
higher than any portion of the building within
ten feet (Figure 8-15).
Vent Connectors – A vent connector directs flue
gases from the furnace to the main vent. TypeB double-wall pipe must be kept one to three
inches from combustible materials or as specified by the vent pipe manufacturer. Single-wall
pipe, when used, must be kept six to nine inches
away from combustibles.
In all cases, vent connectors should be made
as short as possible and pitched upward toward
the main vent at a slope of no less than 1/4
inch per foot. For example, a four-foot long
vent connector should have an upward slope
of at least one inch (1/4 x 4). Keep the number
of elbows to a minimum and use 45° elbows
instead of 90° elbows whenever possible.
8
▼ Figure 8-13.
Typical Type-B Metal Vent System
ADJUSTABLE
0 TO 90° ELBOW
VENT CAP
STORM
COLLAR
FLASHING
ROOF
45°
ELBOW
FIRESTOP
SUPPORT
PLATE
TEE
45°
ELBOW
WATER
HEATER
FURNACE
FLUE
GAS
ALUMINUM
INNER PIPE
INSULATING
AIR SPACE
GALVANIZED STEEL
OUTER PIPE
JOINT LOCK
SYSTEM
TYPE-B VENT PIPE
▼ Figure 8-14.
Vent Termination Heights for Vent Caps 12 Inches
and Smaller
VERTICAL WALL
8' MIN.
VENT
CAP
LOWEST DISCHARGE
OPENING
MINIMUM
HEIGHT
X
12
ROOF PITCH
IS X/12
THE VENT TERMINATION SHOULD NOT BE
LESS THAN 8 FT. FROM A VERTICAL WALL
ROOF PITCH
MINIMUM HEIGHT
FLAT TO 6/12
6/12 TO 7/12
OVER 6/12 TO 7/12
OVER 7/12 TO 8/12
OVER 8/12 TO 9/12
OVER 9/12 TO 10/12
OVER 10/12 TO 11/12
OVER 11/12 TO 12/12
OVER 12/12 TO 14/12
OVER 14/12 TO 16/12
OVER 16/12 TO 18/12
OVER 18/12 TO 20/12
OVER 20/12 TO 21/12
1.0 FEET
1.0 FEET
1.25 FEET
1.5 FEET
2.0 FEET
2.5 FEET
3.25 FEET
4.0 FEET
5.0 FEET
6.0 FEET
7.0 FEET
7.5 FEET
8.0 FEET
▼ Figure 8-15.
Vent Termination Heights for Vent Caps Larger
than 12 Inches
10' MIN.
2' MIN.
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
When an induced-draft furnace is commonvented with another gas appliance, the following
rules apply:
• The vent connector from the smaller capacity appliance may have no more elbows than
the vent from the larger appliance.
• The vent connector for the smaller appliance
must connect to the common vent as high
as possible above the connection from the
larger appliance.
• The connecting tee fitting must always be the
same size as the common vent to reduce turbulence at the connection. For example, if
using a six-inch vent connector, the tee
should also be six inches.
• For instances where two appliances are connected to a manifolded common vent
connector (Figure 8-16), the maximum length
of the common vent connector is determined
by allowing 1.5 feet in horizontal length for
each inch of vent connector diameter. For
example, a six-inch diameter common vent
connector can have a maximum length of
nine feet.
▼ Figure 8-16.
Manifolded Common Vent
General Guidelines for Venting through a
Masonry Chimney – All masonry chimneys
must conform to NFPA Standard 211. Codes
prohibit unlined chimneys from being used to
vent furnaces. Tile-lined masonry chimneys
can be used to vent an induced-draft furnace
only if the furnace is common-vented with a
draft hood-equipped gas appliance. If lined with
a listed liner, a chimney can be used to vent an
induced-draft furnace without the need to be
common-vented with a draft hood-equipped appliance. A chimney must extend at least three
feet above the highest point where it passes
through the roof, and at least two feet higher
than any portion of the building within a horizontal distance of ten feet (Figure 8-17).
Gas code vent selection tables identify the
chimney size (in inches) required to match the
furnace capacity. Sometimes an existing chimney opening will be too big for the furnace and
the proper size chimney liner must be installed.
A double-wall Type-B vent or a flexible metal
chimney liner can be used. Flexible liners
(Figure 8-18) normally come in kits containing
all parts and instructions needed to install the
liner. Consult the furnace manufacturer and
flexible vent manufacturer’s installation literature to determine size, etc.
▼ Figure 8-17.
Minimum Roof Projections for Chimneys
6" DIAMETER
DOUBLEWALL
PIPE
9' MAXIMUM
COMMON VENT
CONNECTOR
OFFSET
COMMON VENT
MAXIMUM COMMON
x 1.5 FT. =
DIAMETER (IN.)
VENT OFFSET (FT.)
6 x 1.5 = 9 FT. MAXIMUM COMMON
VENT OFFSET
3'
2'
10'
▼ Figure 8-18.
Typical Flexible Metal Chimney Liner Kit
Components
RAIN CAP
TOP ADAPTER
SUPPORT ANGLES (2)
FLASHING PLATE
(FORM TO FIT)
INSULATION SLEEVE
TIE BANDS
FLEXI-LINER TUBE
JOINER
(OPTIONAL)
VENT CONNECTOR
BOTTOM ADAPTER
MORTAR SLEEVE
GAS FURNACE INSTALLATION
Table of Contents
Map
References
Section Topics
Condensing Furnace Vent
Systems (Category IV Vents)
Condensing furnaces use a Category IV direct
vent system (Figure 8-19) which operates under positive pressure with respect to the
atmosphere and is powered by the furnace inducer assembly. In a direct vent system, all air
for combustion is taken directly from the outdoors and all flue gases are discharged to the
outdoors. A condensing furnace cannot be
vented using an existing vent or chimney. It
also cannot be common-vented with another
appliance. Some condensing furnaces use indoor air for combustion but direct the flue gases
to the outside under positive pressure.
Because condensing furnaces produce lowtemperature flue gases, most can be vented
using Schedule 40 PVC pipe. The same type
of pipe is also used to supply the furnace with
outdoor combustion air. The two pipes are the
same diameter as determined by the furnace
size, the length of the pipe run, the number of
elbows needed, and the site altitude.
Figure 8-20 shows an example of how pipe sizing tables like those given in the manufacturer’s
installation instructions are used to find the correct size vent and combustion air pipe to use
with a furnace.
8
▼ Figure 8-19.
Category IV Vent Used with Condensing
Furnaces
VENT PIPE
COMBUSTION
AIR PIPE
CONDENSING
FURNACE
▼ Figure 8-20.
Using a Manufacturer’s Vent and Combustion Air Pipe Sizing Table to Determine Pipe Size
General Guidelines for Installing PVC Vent and Combustion Air Pipes – Manufacturer’s
installation instructions provide detailed information for installing the vent and combustion air
piping. Some general guidelines are given here.
Always slope (pitch) the vent pipe back toward the furnace with a slope of at least 1/4 inch per
foot and secure it with straps at least every five feet to prevent sags. This is necessary to allow
condensate to drain back to the furnace for proper disposal.
GAS FURNACE INSTALLATION
Table of Contents
Map
Section Topics
References
QUICK NOTE
If a condensing furnace is replacing an existing gas furnace that was common-vented with another
gas appliance such as a water heater, always check to be sure that the existing vent is not
oversized when venting only the water heater. Most manufacturers provide detailed instructions
for making this check in their installation instructions for the new condensing furnace.
The combustion air and vent pipes always
terminate outside the building either above the
roof (Figure 8-21) or through a sidewall. This
termination can be done either with a two-pipe
termination kit or a concentric single entry termination kit. Instructions for installing these kits
are provided with the kits.
If venting is through a sidewall (Figure 8-22),
make sure the elbow for the combustion air intake points down and the vent points out. Also:
• Avoid terminating the furnace in a corner or
in a confined area such as under a deck to
prevent recirculation into the intake pipe,
which may cause freeze-ups and/or poor
combustion.
• Avoid terminating the furnace near trees or
shrubs to prevent recirculation and plant
damage.
• Avoid terminating the furnace near doors or
windows. This keeps flue products from entering the building and prevents annoying
steam clouds from obscuring vision.
• In areas of heavy snowfall, keep the termination at least 12 inches above the highest
anticipated snow level. A termination too
close to the ground can draw snow, dust, or
leaves into the combustion pipe.
• Clearance dimensions for single-pipe condensing furnace vent terminations are
different from two-pipe condensing furnace
vent terminations.
▼ Figure 8-21.
Rooftop Vent Termination
▼ Figure 8-22.
Sidewall Vent Termination
8
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
FURNACE INSTALLATION GUIDELINES
The methods for installing induced-draft and condensing furnaces are basically the same. The
main area of difference is in the way they are supplied combustion air and the way they are
vented. These guidelines apply to both new and replacement furnace installations. The installation of any furnace must always be done as directed in the manufacturer’s installation instructions
and must comply with any applicable codes and installation practices of the area where it is to be
installed. The installation tasks for induced-draft and condensing furnaces and the general sequence in which they are performed are shown in Figures 8-23 and 8-24, respectively.
▼ Figure 8-23.
Non-Condensing Furnace Installation – Tasks and Sequence
Start
Non-Condensing
Furnace
Installation
Inventory
Equipment,
Materials,
Tools
No
Replacement
Furnace?
No
Check
Location
Confined
Space?
Yes
Yes
Install
Combustion
Air Ducts
Remove
Old Furnace
Install Type-B Metal
and/or Lined Chimney
Vent (if needed)
Locate
Furnace
Install
A/C Coil
(optional)
Purge/Leak
Test Gas
Lines
Complete
Checklist
Install
Supply and
Return Air
Ductwork
and
Humidifier,
EAC, etc.
(optional)
Adjust Gas
Input Rate
Install
Gas Piping
Set
Temperature
Rise
Clean Up Area and
Present Equipment
Manual(s) to Customer
Install
Power and
Control
Components
and Wiring
Set
Thermostat
Heat
Anticipator
Install Vent
Connectors
Check
Safety
Controls
Show Customer How to Operate System
and Perform Simple Maintenance
Install
Condensate
Drains/
Condensate
Pump
(optional)
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
▼ Figure 8-24.
Condensing Furnace Installation – Tasks and Sequence
Start
Condensing
Furnace
Installation
Inventory
Equipment,
Materials,
Tools
Configure
Furnace for
Upflow,
Downflow,
or Horizontal
Installation
As Needed
No
Replacement
Furnace?
Check
Location
Locate and
Level Furnace
Yes
No
Old
Furnace
Common
Vented?
Remove
Old Furnace
Install
A/C Coil
(optional)
Prime
Condensate
Trap with Water
Install
Supply and
Return Air
Ductwork and
Humidifier, EAC,
etc. (optional)
Install
Gas Piping
Purge/Leak
Test Gas
Lines
Complete
Checklist
Install
Power and
Control
Components
and Wiring
Adjust Gas
Input Rate
Clean Up Area and
Present Equipment
Manual(s) to Customer
Install
Combustion
Air
and Vent
Piping
Set
Temperature
Rise
Yes
Install and
Check Venting
of Remaining
Gas
Appliances
Install
Condensate
Drains/
Condensate
Pump
(optional)
Set
Thermostat
Heat
Anticipator
Check
Safety
Controls
Show Customer How to Operate System
and Perform Simple Maintenance
QUICK NOTE
Always make sure all the required parts and tools are available before leaving for the job site.
QUICK NOTE – SAFETY REVIEW
• Only qualified technicians should install furnaces.
• Gas leaks are dangerous. Always check for leaks with soapy water solution prior to firing the burners.
• Whenever possible, shut off all power before working on furnaces. If you must work on a furnace with
power on, remove your watch and other metal jewelry to reduce the shock hazard.
• Before installing or servicing any furnace, take the time to read the manufacturer’s installation and
service literature shipped with the product. Make sure to read and understand all Warnings and
Cautions given in the literature.
GAS FURNACE INSTALLATION
Table of Contents
Map
Section Topics
8
References
Initial Preparation
A detailed list of required materials and a simple drawing showing the intended installation should
be provided to the installer.
If installing a multi-poise furnace, reconfigure the furnace (if required) per the installation instructions before leaving the shop.
Removal of an Existing Furnace
Here are some guidelines for removing an existing furnace:
1. Shut off power to the furnace at the electrical service panel and attach a warning tag to the
panel. Make sure there are no other appliances such as a refrigerator, etc., on the furnace
circuit. Use a voltmeter to confirm that the power is off.
2. At the gas meter, shut off the main gas supply to the building. Disconnect all the gas piping at
the furnace and temporarily plug or cap the gas line. Save the pipe and fittings, as they may be
used for the replacement. For added safety, set the water heater control to OFF. If availability
of the other gas appliances is not needed by the customer, wait until the furnace installation is
complete before turning the gas back on.
3. Remove all power and thermostat wiring from the old furnace. Tape the power leads for added
safety.
4. Disconnect the vent connector and supply and return air ductwork from the old furnace.
If the new furnace is a condensing furnace, it cannot be common-vented with other gas appliances. If the old furnace was common-vented with a water heater or other gas appliance, the
existing vent size must be checked per the gas code tables to make sure it is not oversized for
venting the water heater.
5. Clean up the area in preparation for the new furnace.
Locating the Furnace
For all installations, the furnace location must
always comply with the conditions specified in
the manufacturer’s instructions. Some important location considerations include:
• Install all furnaces so that electrical components are protected from water.
• Always maintain the minimum clearances as
specified on the furnace rating plate and in
the installation instructions (Figure 8-25).
Also, make sure that there is enough clearance in front of and around the furnace for
servicing and cleaning.
• When installed in a hazardous location such
as a residential garage, furnaces must be installed so that the burners are 18 inches
above the floor and they must be protected
from physical damage by vehicles
(Figure 8-26).
• Locate induced-draft furnaces as close to the
vent/chimney as possible. Locate condensing furnaces so that the maximum allowable
lengths of the combustion air and vent pipes
are not exceeded.
• Locate the furnace as close to the center of
the air distribution system as possible.
▼ Figure 8-25.
Typical Clearances to Combustibles Data Given in
Manufacturer’s Installation Instructions
▼ Figure 8-26.
Installation in a Hazardous Location
18 INCH MINIMUM
TO BURNERS
GAS FURNACE INSTALLATION
Table of Contents
Map
References
Section Topics
• Avoid installing furnaces that use indoor air
for combustion near sources of contamination such as those that can exist in laundry
rooms (Figure 8-27).
• Condensing furnaces installed in an unconditioned space where the ambient
temperatures can drop below freezing must
have adequate freeze protection. Freeze
protection methods are described later in this
section.
• The cooling coil (if used) must be installed
on the supply side of the furnace to avoid
condensation in the heat exchangers.
▼ Figure 8-27.
Avoid Contaminants in the Combustion Air
• AEROSAL SPRAYS
• DETERGENTS
• BLEACHES
• CLEANING SOLVENTS
• SALTS
• AIR FRESHENERS
• OTHER HOUSEHOLD
PRODUCTS
Induced-Draft Furnace
Combustion and Ventilation
Adequate combustion and ventilation air for a
furnace must be supplied from either inside or
outside the building, depending on whether the
furnace is installed in an unconfined or confined space. An unconfined space is one that
has a volume of at least 50 cubic feet for each
1,000 Btuh of input for all appliances in the
space (Figure 8-28). For example, a 100,000
Btuh input furnace would require a volume
greater than 5,000 cubic feet to be considered
unconfined. The volume for any room can be
calculated by multiplying the room’s length by
its width and height.
Volume = L x W x H
Confined spaces (Figure 8-29) are defined
as those having less than 50 cubic feet per
1,000 Btuh of input. If the same 100,000 Btuh
input furnace was installed in a room with a
volume of less than 5,000 cubic feet, that installation would be considered in a confined
space.
Whether the furnace is installed in a confined
or unconfined space, adequate air must be
made available for combustion. In older, loosely
constructed homes, adequate air can be supplied by infiltration. If the home is newer and of
tighter construction and/or infiltration cannot
supply adequate air, the air must be brought in
from outdoors.
By code, the combustion air requirements for
all gas furnaces are the same. Only the sizes
of the ducts, grille openings, etc. differ based
on the specific model of furnace and its input in
Btuh. A confined space must have two permanent openings, one within 12 inches of the
ceiling and the other within 12 inches of the
floor. Grilles or louvers installed over openings
must be permanently open.
8
▼ Figure 8-28.
Furnace in an Unconfined Space
CONNECTED VOLUME
OF SPACE IS GREATER
THAN 50 CU. FT./1,000
BTUH
▼ Figure 8-29.
Furnace in a Confined Space
CONFINED SPACE:
VOLUME LESS THAN
50 CU. FT./1,000 BTUH
GAS FURNACE INSTALLATION
Table of Contents
Map
Supplying Outdoor (Outside) Air to a Confined Space – Figure 8-31 shows the
requirements for bringing outdoor combustion
air into a confined space. These requirements
are outlined here.
• If combustion air is brought in through vertical ducts, the openings and ducts must have
at least one square inch of free area per
4,000 Btuh of the total input for all equipment
within the confined space. (See Table 8-3.)
• If combustion air is brought in through horizontal ducts, the openings and ducts must
have at least one square inch of free area
per 2,000 Btuh of the total input for all equipment within the confined space. (See
Table 8-4.)
• The cross-sectional area of any vertical or
horizontal duct must be equal to or larger than
the free area of the opening to which it connects. Rectangular duct must not be less
than three inches wide or high.
▼ Table 8-2.
Sizing Air Openings into a
Confined Space
References
Section Topics
Supplying Inside Air to a Confined Space –
Figure 8-30 shows the requirements for bringing in combustion and ventilation air from an
adjacent unconfined space into a confined
space. These requirements are outlined here.
• Each opening must have at least one square
inch of free area per 1,000 Btuh of the total
input for all equipment in the confined space,
but not less than 100 square inches per opening (Table 8-2). The free area of grilles and
louvers can be found in the manufacturer’s
literature. When used, screens must not be
smaller than 1/4-inch mesh.
• If a furnace is installed on a raised platform
to provide a return air plenum, and return air
is taken directly from the hallway or space
adjacent to the furnace, then all air for combustion must come from the outdoors.
8
▼ Figure 8-30.
Confined Space Requirements for Use of Inside
Air for Combustion and Ventilation
▼ Figure 8-31.
Confined Space Requirements for Use of Outside
Air for Combustion and Ventilation
▼ Table 8-3.
Sizing Vertical Ducts into a
Confined Space
▼ Table 8-4.
Sizing Horizontal Ducts into a
Confined Space
Furnace Input
(Btuh)
Free Area
per Opening
(Square Inches)
Furnace
Input (Btuh)
Free Area
per Opening
(Square Inches)
Round Pipe
Diameter (Inches)
Furnace
Input (Btuh)
Free Area
per Opening
(Square Inches)
Round Pipe
Diameter (Inches)
44,000
100
44,000
11.0
4
44,000
22.0
6
66,000
100
66,000
16.5
5
66,000
33.5
7
88,000
100
88,000
22.0
6
88,000
44.0
8
110,000
110
110,000
27.5
6
110,000
55.0
9
132,000
132
132,000
33.0
7
132,000
66.0
10
154,000
154
154,000
38.5
7
154,000
77.0
10
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
Installing and Leveling the
Furnace
Once a furnace is in position, it should be plumb and level within the specifications given in the
installation instructions. Achieving the proper plumb and level is especially important with condensing furnaces because of the need for proper drainage of the condensate.
For a basement installation, it may be necessary to elevate the furnace on a pad or blocks to
prevent corrosion. Seal the bottom opening of the furnace if it is not being used.
When installing a downflow furnace on a combustible floor, it must be mounted on a downflow
subbase kit per the instructions provided with the kit.
Installing the Air Distribution
System Ductwork
As part of the pre-installation survey, the correct sizes and dimensions of the ductwork
should have been determined. Refer to Section 6 for guidelines pertaining to the installation
of duct systems. Before installing any ductwork,
the return air opening in the furnace should be
cut or otherwise prepared. It is recommended
that metal snips be used instead of a power
tool. If power tools are used, cover the fan
motor so metal chips do not get into the motor
windings. BE CAREFUL WHEN WORKING
AROUND SHARP METAL EDGES.
If an evaporator (cooling coil) is being installed, the coil enclosure and coil should be
mounted on the furnace. Following this, the
plenum and supply ductwork can be installed.
Before the return drop is hung and secured to
the furnace, install any humidifier, electronic air
cleaner, or external filter rack. After the
ductwork is installed, make sure that the furnace is still level and plumb.
Installing Gas Piping
All gas piping must comply with local codes and
the manufacturer’s installation instructions. For
information about cutting, threading, and assembling gas piping, refer to Section 5.
The size of the gas supply pipe for the furnace is determined by many factors
(Figure 8-32). For the purpose of sizing, a rule
of thumb is to add about three equivalent feet
of pipe for each fitting (elbow, tee, or valve) used
in the run. The quantity of gas a furnace consumes, in cubic feet per hour (CFH), can be
calculated by dividing the furnace’s input capacity (Btuh) by the heating value of the gas as
obtained from the local gas utility. The main
gas supply pipe size is calculated by adding
the flow of all gas-fired appliances in the building.
Once the quantity of gas and the length of
the gas pipe run has been determined, find the
pipe size using sizing tables in the gas code
manual or installation instructions (Figure 8-33).
An example of its use for a furnace with an input of 132,000 Btuh is shown. Assume that
the total piping length is 45 feet, including an
allowance for fittings.
➧ CAUTION
▼ Figure 8-32.
Gas Piping Size
•
•
•
•
•
FURNACE INPUT
PRESSURE DROP
LENGTH
FITTINGS
SPECIFIC GRAVITY
▼ Figure 8-33.
Typical Gas Pipe Sizing Table Given in
Manufacturer’s Installation Instructions
GAS FURNACE INSTALLATION
Table of Contents
Map
References
Section Topics
First, the gas quantity in cubic feet per hour
is calculated, assuming the heating value of the
gas is 1,050 Btu/cu. ft. The gas quantity is:
QUICK NOTE
Calculating Gas Flow in Cubic Feet Per
Hour (CFH):
CFH = 132,000 ÷ 1,050 = 125.7 cu. ft./hr.
Using the table, read across the top row for
the pipe length. The 45-foot length would use
the next higher length, 50 feet. Read down this
column to the nearest gas quantity greater than
125.7 cu. ft./hr., which is 151 cu. ft./hr. In this
example, the proper pipe size is 3/4 inch. The
pipe size may vary, depending on the specific
gravity and pressure drop in the pipe. Tables
to allow for these factors are available in the
code books.
The gas pipe should contain a manual shutoff
valve, a drip leg to trap moisture and sediment,
and a ground joint union (Figure 8-34). The
shutoff valve must be in a visible and accessible location so that it can be quickly and easily
turned off in case of an emergency. The sediment trap prevents dirt or moisture from
entering the gas controls. A bottom outlet cap
allows for cleaning.
Support the gas piping at least every six feet.
If propane is the fuel gas, use a joint compound
(pipe dope) that is resistant to propane.
Once the gas piping is installed, turn the gas
on and purge the line of air by loosening the
union slightly until an odor of gas is noticed,
then retighten it. Following this, check all joints
for leaks with soapy water or a leak detecting
solution.
CFH =
Input (Btuh)
Gas Heating Value (Btu/Cu. Ft.)
Where:
• Input (Btuh) = The furnace full-rated
input heating capacity from its rating
or nameplate.
• Gas Heating Value = Heating value
of the gas as obtained from the local
gas utility.
▼ Figure 8-34.
Typical Furnace Gas Piping
GAS SUPPLY
MANUAL
SHUTOFF
VALVE
SEDIMENT
TRAP
UNION
Installing Power and Control
Wiring
All wiring must comply with local codes and the
manufacturer’s installation instructions. For
detailed guidelines on installing power and control circuit wiring, refer to Section 7.
Supply power to the furnace must use a dedicated line equipped with a correctly sized fuse
or circuit breaker (Figure 8-35), with a dedicated ground wire attached to the furnace
ground and to the earth ground in the electrical
panel. Establishing a good ground is essential
to proper furnace operation. Failure to do so
can result in several furnace operating problems. A disconnect switch should also be
installed at the furnace. When the power wiring is completed, leave the power turned off
until you are ready to start up and check out
the furnace.
When installing the room thermostat and control wiring, always install at least four-conductor
thermostat wire, even if installing the furnace
in a heating-only system. Note that many thermostats use a 24V common wire, requiring that
a five-conductor thermostat wire be installed.
This will simplify the installation of air conditioning at a later date.
8
▼ Figure 8-35.
Installing Power to the Furnace
DEDICATED POWER
LINE AND GROUND
WIRE
DISCONNECT
SWITCH
ELECTRICAL
SERVICE
PANEL
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
QUICK NOTE
When installing gas pipe:
• Use the proper length of pipe and adequate support to avoid stress on the gas valve. Undue stress
may cause a gas leak, resulting in a fire or personal injury.
• If a flexible connector is required or allowed by code, black iron pipe must be installed at the gas
valve and extend a minimum of two inches outside the furnace casing.
• Connect the gas pipe to the furnace using a backup wrench to avoid damaging the gas valve.
The installation of power and control wiring
includes the wiring needed for accessories such
as an electronic air cleaner or humidifier. These
should be correctly wired per the instructions
supplied with each accessory. They also must
be wired to the correct terminals on the
furnace’s control board (Figure 8-36).
▼ Figure 8-36.
Typical Furnace Control Board Electrical
Connections
Installing Venting
All venting must comply with local codes and
the manufacturer’s installation instructions.
Furnace venting was covered in detail earlier
in this section.
Installing Condensate Drains
The installation of a condensate drain is necessary for condensing furnaces, when a cooling
coil is mounted on the furnace, or when a humidifier is installed (Figure 8-37). All drain
connections must be terminated into an open
or vented drain. If that is impractical, a condensate pump and piping must be installed to
pump the condensate into a suitable drain.
Condensate pumps were covered earlier in this
section. To ensure proper operation, the
furnace condensate trap must be primed
with water before operating the furnace.
If a condensing furnace is installed in an attic, crawlspace, or other area where
temperatures can drop below freezing, an accessory heat tape kit must be installed to
prevent the condensate trap and drain line from
freezing (Figure 8-38). The heat tape kit is installed per the instructions supplied with the kit.
▼ Figure 8-37.
Typical Field Condensate Drain
➧ CAUTION
OPEN STAND
PIPE FOR AC
AND/OR
HUMIDIFIER
DRAIN
TEE
TO OPEN
DRAIN OR
CONDENSATE
PUMP
CONDENSING
FURNACE
CONDENSATE
TRAP
▼ Figure 8-38.
Typical Condensate Trap Freeze Protection Using
Heat Tape
GAS FURNACE INSTALLATION
Table of Contents
Map
Section Topics
8
References
Start-Up and Checkout
The furnace must always be started up and fully checked out per the installation instructions
before the technician leaves the site.
Normally, the start-up procedure begins by turning on power to the furnace and making general
component and operational checks. If not previously accomplished, it also includes turning on the
gas and purging the gas lines and priming the condensate trap with water (if applicable). While
performing the various start-up tasks, the Gas Furnace Installation and Start-Up Checklist located on page 158 of this book should be used to check off each item when completed. Use of a
checklist makes sure that an organized and consistent procedure is followed and that no area of
the installation or checkout is overlooked.
After the initial start-up tasks have been performed, the gas input rate, temperature rise, and
thermostat anticipator adjustments are made per the installation instructions. This is followed by
a checkout of the safety controls. Guidelines for making the adjustments and safety checks are
described here.
Adjusting Gas Input Rate – The burners must
be fired at full input to prevent condensation in
the primary heat exchanger and/or vent. The
correct manifold pressure for full burner input
can be found by following the procedure given
in the installation instructions or by using a
manifold pressure calculator (Figure 8-39). Use
of the manifold pressure calculator for installations below 2,000 feet above sea level greatly
simplifies the procedure. For higher altitudes,
follow the manufacturer’s installation instructions. Instructions for using the manifold
calculator are printed on the calculator. An example of its use follows.
1. From the local gas utility, get the yearly average heat content and specific gravity of the
natural gas supplied in the area. In this example, assume a heat content of 1,120 Btu’s
per cubic foot and a specific gravity of .62.
2. Check the size of the orifices in the burner
manifold and count the number of burners.
In this example, #45 orifices are used with
the four burners. Consult the furnace rating
plate to find the total furnace input, which is
80,000 Btuh in this example (Figure 8-40).
3. Using calculator Step 1, align the total furnace input of 80,000 with the four burners to
obtain the input per burner of 20,000 (Figure
8-41). Note that the calculator has two similar sides. Side 1 is used with furnaces having
one to three burners. Side 2 is used with furnaces having four to eight burners.
▼ Figure 8-39.
Natural Gas Furnace Manifold Pressure
Calculator
▼ Figure 8-40.
Find Total Input (Btuh) for Furnace on Rating Plate
▼ Figure 8-41.
Example of Manifold Calculator, Step 1
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
4. Using calculator Step 2, align the input per
burner of 20,000 with the gas heat content
of 1,120 (Figure 8-42). Then find a key value
that is nearest the #45 orifice. The key value
in this example is H.
5. Using calculator Step 3, align the key value
of H with the .62 specific gravity value
(Figure 8-43). This gives the correct manifold pressure, in inches of water, that will
ensure that the burner is fired at its full input.
In this example, the correct manifold pressure is 3.2 inches of water.
If the calculator indicates a manifold pressure outside the range of 3.2 to 3.8 inches
water column, the burner orifice size must
be increased or decreased per the calculator. Do not redrill or peen burner orifices.
Obtain the correct orifice from your distributer.
Once the required manifold pressure is calculated, the furnace manifold pressure must be
adjusted to this value. This procedure involves
connecting a manometer to the manifold pressure tap on the gas valve (Figure 8-44) or the
manifold to measure the gas pressure. Following this, the furnace power is turned on and
the burners fired. With the burners firing, the
manifold pressure is measured and the gas
valve regulator adjustment screw is set to obtain the required manifold pressure. Do not
adjust for less than 3.2 in. w.c. or more than
3.8 in. w.c. for natural gas.
▼ Figure 8-42.
Example of Manifold Calculator, Step 2
Adjusting Temperature Rise – Temperature
rise is the difference between the air temperature entering and leaving the furnace. The
amount of temperature rise gives an indication
of whether adequate air is flowing across the
furnace heat exchanger. The correct temperature rise range for a furnace can be found on
the furnace rating plate (Figure 8-45). The correct amount of temperature rise is important in
all furnaces. In condensing furnaces, if too
much air passes over the heat exchangers, condensing can take place in the primary heat
exchanger, causing corrosion and failure. In
induced-draft furnaces, too much air can cause
condensation in the heat exchanger and vent.
If too little air passes over the heat exchangers, the resultant overheating may cause
premature failure.
▼ Figure 8-44.
Measuring Manifold Pressure
▼ Figure 8-43.
Example of Manifold Calculator, Step 3
➧ CAUTION
▼ Figure 8-45.
Required Temperature Rise Range Shown on
Furnace Rating Plate
FOR INSTALLATION IN BUILDING CONSTRUCTED ON-SITE
FOR INDOOR INSTALLATION IN EITHER HEATED OR UNHEATED SPACES
NACE
TION
MANUFACTUR
10000091
GAS INPUT
EQUIPPED FOR
NATURAL
0.50
OVER
OTECTION
14.0
IN W.C.
15
IN W.C.
MANUFACTURERS
ES, FOLLOW THE
LATION AND ALEARANC E FROM
CHART AT RIGHT
AIR TEMP.
RISE
40F—70F
50,
DESIGNED MAX. OUTLET
AIR TEMPERATURE
MOTOR THERMALLY OVERLOAD PROTECTED 115V 60
AMPS
MINIMUM PERMISSIBLE GAS SUPPLY PRESSURE
FOR PURPOSES OF INPUT ADJUSTMENT
TOP
SIDES
BACK
FRONT
DRAFT HOOD
8"
6"
*
ALCOVE
6"
4. 5
SINGLE
WITH DRAFT HOOD ON FRONT OF FURNACE.
* BACK: 8"
18" WITH DRAFT HOOD ON BACK OF FURNACE.
LINE CONTACT ONLY PERMISSIBLE IF BETWEEN LINES FORMED BY
GAS FURNACE INSTALLATION
Table of Contents
Map
8
References
Section Topics
QUICK NOTE
Before making temperature rise checks, make sure that the furnace is fired at its full input, the
furnace air filter is clean, and all supply and return registers are open and unrestricted. If the
furnace is equipped with a bypass humidifier, the damper in the bypass duct must be closed.
LINE OF SIGHT
RETURN
SUPPLY
ET-5000
ELECTRONIC
THERMOMETER
FURNACE
ET-5000
ELECTRONIC
THERMOMETER
FOR INSTALLATION IN BUILDING CONSTRUCTED ON-SITE
FOR INDOOR INSTALLATION IN EITHER HEATED OR UNHEATED SPACES
ACE
ION
MANUFACTUR
10000091
GAS INPUT
EQUIPPED FOR
NATURAL
0.50
OVER
OTECTION
14.0
IN W.C.
15
AIR TEMP.
RISE
40F—70F
50,
DESIGNED MAX. OUTLET
AIR TEMPERATURE
MOTOR THERMALLY OVERLOAD PROTECTED 115V 60
AMPS
MINIMUM PERMISSIBLE GAS SUPPLY PRESSURE
FOR PURPOSES OF INPUT ADJUSTMENT
IN W.C.
ANUFACTURERS
ES, FOLLOW THE
SIDES
BACK
FRONT
DRAFT HOOD
8"
6"
*
ALCOVE
6"
*
LATION AND ALEARANC E FROM
CHART AT RIGHT
4. 5
TOP
SINGLE
BACK: 8" WITH DRAFT HOOD ON FRONT OF FURNACE.
18" WITH DRAFT HOOD ON BACK OF FURNACE.
SUPPLY TEMPERATURE – RETURN TEMPERATURE = TEMPERATURE RISE
128° F – 70° F = 58° F
THE TEMPERATURE RISE OF 58° F FALLS SLIGHTLY ABOVE THE MIDPOINT
(55° F) OF THE RANGE OF 40° F TO 70° F SHOWN ON THE FURNACE
INFORMATION PLATE. THIS INDICATES THAT THE AIRFLOW IS ADEQUATE
AND NO AIRFLOW ADJUSTMENT IS NEEDED.
40° F
70° F
RISE RANGE
MIDPOINT 55° F
▼ Figure 8-47.
Clamp-On Ammeter Connected for Thermostat
Heat Anticipator Adjustment
ROOM THERMOSTAT
TERMINALS
R
Y
W
G
CLAMP-ON
VOLT/AMMETER
EXAMPLE:
ng
Ra
Off
On
Min
.
Ma
x.
9 LOOPS
10 PASSES
e
FROM UNIT
Hz
Adjusting the Thermostat Heat Anticipator
– For all room thermostats, the heat anticipator
or cycle rate setting must be adjusted correctly
to prevent short cycling of the furnace. Short
cycling prevents the furnace from coming up to
operating temperature, causing condensation
to occur in the heat exchanger and/or vent.
Short cycling also contributes to poor indoor
comfort. The procedure for anticipator adjustment is given in the installation instructions and
briefly outlined here.
When properly adjusted, the thermostat heat
anticipator is set to match the current draw of
the primary control in the furnace. As shown in
Figure 8-47, this is done by wrapping an insulated wire ten times around the jaws of a
clamp-on ammeter, then connecting the leads
to the thermostat R and W terminals. After furnace operation has stabilized, calculate the
actual current draw by taking the meter reading (5 amps, Figure 8-47) and dividing it by ten
for ten turns of wire. Based on this measurement, the heat anticipator adjustment would be
set to 0.5 amps (5 amps ÷ 10 = 0.5 amps). If a
microprocessor or electronic thermostat is being used, set the cycle rate at three per hour or
per the thermostat manufacturer’s instructions.
Regardless of the type of thermostat used, at
least two complete burner cycles should be witnessed to ensure proper operation before
leaving the job.
▼ Figure 8-46.
Example of a Temperature Rise Measurement
Dig
ital
AM Clam
ME p-On
TER
The procedure for measuring temperature rise
is provided in the installation instructions. It is
briefly outlined here and an example is shown
in Figure 8-46.
To measure temperature rise, drill a temperature measurement hole in the return duct near
the furnace and another in the supply duct out
of the line of sight of the heat exchangers. Then
turn on the furnace and operate it for about ten
minutes to allow the temperatures to stabilize.
Measure the supply and return air temperatures with an accurate thermometer, then
calculate the temperature rise by subtracting
the return air temperature from the supply air
temperature. Ideally, the temperature should
be slightly above the midpoint of the range
shown on the furnace information plate. If the
temperature rise is too low, decrease the blower
speed to reduce the airflow; if too high, increase
the blower speed to increase the airflow.
5.0 AMPS ON AMMETER = 0.5 AMPS FOR HEAT ANTICIPATOR SETTING
10 PASSES AROUND JAWS
Checking Safety Controls – Proper operation of the primary limit control, pressure switch, and
any other safety controls must always be checked as directed in the installation instructions before leaving the job.
GAS FURNACE INSTALLATION
Table of Contents
Map
Section Topics
Primary Limit Switch – The main limit switch
shuts off the burners if the furnace overheats
because of a restricted air supply or blower
motor failure. The operation of the limit switch
can be checked with the furnace burners firing
and blower operating by slowly restricting the
return air (Figure 8-48) until the limit switch
shuts off the burners. This confirms limit switch
operation. As soon as the burners shut down,
unblock the return air opening to permit normal
operation.
Pressure Switch – The pressure switch “proves”
the operation of the draft inducer fan. Its operation can easily be checked by disconnecting
the sensor tube from the pressure switch
(Figure 8-49) and setting the room thermostat
to call for heat. There should be no burner operation.
References
▼ Figure 8-48.
Slowly Restrict Return Air for Limit Switch Check
CARDBOARD
▼ Figure 8-49.
Disconnect Tube to Check Pressure Switch
Final Checks, Adjustments, and
Tasks
With the furnace operational, the following
checks should be made to complete the installation.
• Check all other functions of the room thermostat such as cooling operation and
continuous blower operation.
• Check for correct operation of accessories
such as an electronic air cleaner or humidifier, if installed.
• Check the furnace and ductwork for any unusual noises or vibration.
• Adjust the balancing dampers in each branch
duct for correct operation.
• If applicable, light the pilot on the water heater
and confirm that the water heater is operating. Confirm proper vent operation.
• Clean up the work area when done.
Before leaving the job, the installer should
explain the operation of the complete comfort
system to the customer (Figure 8-50). Describe
how the furnace operates and run the furnace
through a complete cycle so the customer can
see and hear the normally operating system.
If installed, demonstrate air conditioning operation and operation of any accessories. After
the demonstration, present the customer with
the owner’s operating and service manual(s).
Fill out the warranty card and give it to the customer. Attach the dealer sticker to the furnace.
8
▼ Figure 8-50.
Explain the Operation of the System to the
Customer
SPLIT SYSTEM INSTALLATION
9
▼SPLIT SYSTEM INSTALLATION
SECTION 9
INTRODUCTION
This section provides guidelines for the installation of split system air conditioning and/or heat
pump systems and related accessories. It is not intended to teach refrigeration or air distribution
theory; instead, it describes the different kinds of equipment used in split comfort systems and the
methods used to install them. This section presumes that the proper type of equipment and
related accessories have been selected and purchased by a qualified engineer or salesperson
based on a survey of the job.
SPLIT SYSTEM MENU
Split Systems and Components
Split Cooling Systems
Split Heat Pump Systems
Indoor Evaporator Coil Units
Fan Coil Units
Accessories
Accessories Used with Indoor Units
Accessories Used with Outdoor Units
Split System Installation Guidelines
Installing the Indoor Equipment
Installing the Outdoor Equipment
Installing Refrigerant Tubing Lines
Start-Up and Checkout
Final Checks, Adjustments, and Tasks
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
9
References
Section Topics
SPLIT SYSTEMS AND COMPONENTS
Split systems are those in which the system’s refrigeration components are housed in two or
more separate and matched units, one located outdoors and the other indoors. There are two
types of split systems: cooling systems and heat pumps.
Split Cooling Systems
▼ Figure 9-1.
Typical Split Cooling System with Indoor
Evaporator Coil Mounted on a Furnace
Split cooling systems provide cooling only. They
consist of a condensing unit located outdoors
and an evaporator coil located indoors. When
functioning as part of a central air conditioning
system where heating is provided by a furnace,
the indoor evaporator coil is usually mounted
in the furnace’s supply air plenum (Figure 9-1).
The furnace’s blower serves to circulate the
cooled air through the system ductwork. In installations not involving a furnace, the
evaporator coil is mounted within an air handler (fan coil) for the cooling system. Fan coil
units are covered later in this section.
Figure 9-2 shows the basic components used
in a split system air conditioner. The outdoor
condensing unit consists of the compressor,
condensing coil, fan, and controls. The compressor creates the pressure difference needed
to make the refrigerant flow. The condensing
coil is a heat exchanger that transfers the heat
absorbed by the refrigerant flowing through the ▼ Figure 9-2.
Basic Split Cooling System
indoor evaporator coil to the cooler outdoor air.
The indoor fan coil unit contains the evapoCOOL AIR
rator coil and metering device. The evaporator
OUTPUT
coil is a heat exchanger in which the heat from
HOT AIR
OUTPUT
the indoors is transferred to and absorbed by
EVAPORATOR
CONDENSING
the refrigerant flowing through the coil. The
COIL
COIL
metering device provides a pressure drop that
lowers the boiling point of the refrigerant just
before it enters the evaporator.
SUCTION
A line set consisting of suction and liquid reLINE
frigerant lines connects the outdoor unit to the
LIQUID
indoor unit. The suction line carries heat-laden
LINE
METERING
OUTDOOR UNIT
DEVICE
refrigerant gas flowing from the evaporator coil
to the compressor in the outdoor unit. The liqINDOOR UNIT (FAN COIL)
uid line carries liquid refrigerant, formed in the
condenser of the outdoor unit, to the expansion device in the indoor unit.
The size or capacity of a split cooling system is measured by the amount of cool air that it puts
out in Btu’s per hour (Btuh), often expressed in tons. The number of tons of capacity can be
calculated by dividing the unit’s Btuh rating by 12,000. For example, an output of 36,000 Btuh is
equal to three tons (36,000 ÷ 12,000 = 3). The efficiency of a split system is rated in terms of its
seasonal energy efficiency ratio (SEER). This rating is expressed as a number. The higher the
number, the higher the efficiency. Capacity and efficiency information for the different units can be
found in the manufacturer’s product literature.
Warm
COMPRESSOR
r
oo
Ind
rm ir
A
Wa
Outs
Air ide
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Split Heat Pump Systems
Split heat pump systems can provide both heating and cooling by reversing the flow of
refrigerant in the system.
The outdoor and indoor units of a split heat
pump system look similar to the units used with
a split cooling system, but contain additional
components because the system performs a
dual role.
As shown in Figure 9-3, the split heat pump
operates the same way in the cooling mode as
a split cooling system. For cooling, the outdoor
coil discharges heated air and the indoor coil
discharges cooled and dehumidified air. In the
heating mode, the direction of refrigerant flow
and the functions of the coils in the indoor and
outdoor units are reversed by the action of the
reversing valve (Figure 9-4). Reverse cycle heat
is the term used for heat pump heating. The
indoor coil becomes the condensing coil and
the outdoor coil becomes the evaporator coil.
This allows the outdoor coil to absorb heat from
the outside air and transfer this heat via the
indoor coil to the indoors.
The line set consisting of vapor and liquid
refrigerant lines connects the outdoor unit to
the indoor unit. The vapor line carries superheated refrigerant gas from the indoor coil to
the compressor during the cooling cycle and
the hot gas discharged from the compressor to
the indoor coil in the heating cycle. The liquid
line carries liquid refrigerant between the units
during both cycles of operation.
Indoor Evaporator Coil Units
The indoor evaporator coil used in a split cooling system is typically mounted on a furnace in
its own case or in the field-fabricated supply air
plenum. If a cased coil is used, the plenum attaches directly to the discharge end of the
cabinet. There are several types of coils. The
“A” coil has two coil slabs connected together
in a “A” arrangement (Figure 9-5) with a drip
pan under each slab and a common condensate drain line. A variation of the “A” coil, called
an “N” coil, provides more coil surface than is
possible with an “A” coil. Slant coils are single
coils mounted at an angle. Both the “A”-type
and slant coils are commonly used in upflow or
downflow applications. A horizontal coil is a vertical coil positioned for horizontal airflow
applications. A condensate drain must be provided for all types of coils to remove the
condensate water from the drip pan.
The indoor evaporator coil must match the
outdoor condensing unit in order to produce the
rated capacity and efficiency of the system.
Also, the furnace blower or fan in the fan coil
must be able to deliver the required CFM
against the external static pressure of the coil,
filter, and air distribution system. Depending on
the type of coil and/or system, one of two types
of metering devices can be used: a thermal
expansion valve (TXV), or a fixed-orifice device (Figure 9-6).
9
▼ Figure 9-3.
Basic Heat Pump Split System – Cooling Operation
COOL AIR
OUTPUT
FAN OFF DURING
DEFROST ONLY
HOT AIR
OUTPUT
REVERSING
VALVE
ENERGIZED
INDOOR COIL
OUTDOOR
COIL
ACCUMULATOR
VAPOR
LINE
Warm
Outs
Air ide
COMPRESSOR
oor
METERING
DEVICE
(METERING)
Air
Ind
LIQUID
LINE
METERING DEVICE
(BYPASSED)
INDOOR UNIT
OUTDOOR UNIT
▼ Figure 9-4.
Basic Heat Pump Split System – Heating Mode
Operation
WARM AIR
OUTPUT
COLDER AIR
OUTPUT
REVERSING VALVE
DEENERGIZED
INDOOR COIL
OUTDOOR
COIL
ACCUMULATOR
VAPOR
LINE
Cold
COMPRESSOR
r
oo
Ind
rm ir
A
Wa
METERING
DEVICE
(BYPASSED)
Outs
Air ide
LIQUID
LINE
METERING DEVICE
(METERING)
INDOOR UNIT
OUTDOOR UNIT
▼ Figure 9-5.
Indoor Coil Units
AIRFLOW
AIRFLOW
DRIP PAN
DRIP PAN
DRIP PAN
"A" COIL
SLANT COIL
AIRFLOW
DRIP PAN
HORIZONTAL COIL
▼ Figure 9-6.
Metering Devices
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
9
References
Section Topics
In a split heat pump system, the indoor coil
can be mounted in a fan coil, or it can be
mounted on a gas- or oil-fired furnace in the
same manner as done in some split cooling systems. The indoor coil must have the capacity
and physical size to function both as an evaporator and condensing coil, depending on the
operating mode.
Fan Coil Units
A fan coil unit (Figure 9-7) can be used as the
indoor unit in both split cooling and split heat
pump systems. It consists of the indoor coil,
metering device, blower, and may also include
electric resistance heater elements used to supply supplemental heat. The blower draws the
air from the return air duct system through the
coil, then blows it through the electric resistance
heaters, discharging the air into the supply duct
system.
Fan coils can be used in upflow, downflow,
or horizontal applications. Fan coils are selected to match the outdoor condensing or heat
pump unit to produce the required capacity and
efficiency. The fan coil blower must be able to
deliver the required CFM against the external
static pressure of the coil, filter, and air distribution system.
In hot, dry climates, an oversized evaporator is sometimes used in cooling systems. This
is called mix-matching.
ACCESSORIES
There are many accessories that can be used
to enhance the operation of split systems.
Some of the more common ones are briefly
described here. All such accessories should
be installed per the manufacturer’s installation instructions.
Humidifiers (Figure 9-8), electronic air cleaners, and condensate pumps are commonly
used with the indoor fan coil unit in both split
cooling and heat pump systems. These accessories are described in detail in Section 8 of
this book. Other accessories used with indoor
units are described in the paragraphs that follow.
▼ Figure 9-7.
Typical Fan Coil
EVAPORATOR
COIL
SUPPORT
RAIL
BLOWER
ASSEMBLY
ELECTRIC
RESISTANCE
HEATERS
AIR
AIR
UPFLOW
APPLICATION
PRIMARY
CONDENSATE
DRAIN
REFRIGERANT
CONNECTIONS
SECONDARY
CONDENSATE
DRAIN
HORIZONTAL RIGHT
APPLICATION
▼ Figure 9-8.
Humidifier and Electronic Air Cleaner Used with a
Fan Coil
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Accessories Used with Indoor
Units
Electric Heaters – Accessory electric heaters
(Figure 9-9) are used to provide additional
stages of heat (supplemental heat) in split heat
pump systems or to provide the primary source
of heat in split cooling systems. They come in
a range of sizes and are available with fuses or
with circuit breaker protection. Normally, heater
assemblies are fully wired and ready for installation in a fan coil unit.
Most heat pump systems with supplemental
heat use a one-stage cool, two-stage heat type
of thermostat. When cooling is required, the
single-stage cooling provides indoor space control. Heating operation is more complex. On a
call for heat, the first stage allows the compressor to operate. If the building’s heat loss is
greater than the unit’s capacity and compression heat cannot satisfy the demand, stage two
will automatically energize the supplemental
resistance heaters either directly or in accordance with outdoor thermostat settings.
The number of outdoor thermostats used to
control successive stages of supplemental heat
is determined by how the manufacturer has divided the heater element packages into
controllable sections or stages. One stage
should use one outdoor thermostat, two stages
should use two thermostats, etc. The outdoor
thermostat (Figure 9-10) opens on a rise in temperature. It has an extended bulb with a
capillary tube to sense outdoor temperatures.
The setting can be adjusted to any desired
setpoint within the range of approximately 0° F
to 50° F by turning a dial. Room thermostats
used with heat pumps normally have a supplementary heat switch. In the event of a
compressor failure, this switch can be used to
bypass any outdoor thermostats, allowing the
electric heaters to provide heat.
9
▼ Figure 9-9.
Electric Heating Elements Used in a Fan Coil Unit
ELECTRIC RESISTANCE
HEATERS INSTALLED HERE
EVAPORATOR
BLOWER
ASSEMBLY
ELECTRIC
RESISTANCE
HEATERS
AIR
ELECTRIC RESISTANCE
HEATER ELEMENTS
AIR
▼ Figure 9-10.
Typical Outdoor Thermostat
Blower-Off Delay Relay – A blower-off delay relay allows the indoor blower motor to operate for
a brief period after the compressor cycles off to capture the residual cooling capacity of the coil.
Accessories Used with Outdoor Units
The accessories described below can be used with condensing units or heat pump outdoor units.
These accessories can be either factory or field installed.
Low-Ambient Temperature Controller – A low-ambient temperature controller is a head pressure control device that is activated by a temperature sensor. It is typically used on light commercial
cooling or heat pump systems that need to operate in the cooling mode at outdoor temperatures
below 55° F. It controls the outdoor fan motor speed in response to the saturated condensing
temperature to maintain the proper condensing temperature at any ambient temperature, typically down to -20° F.
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
Section Topics
9
References
The control (Figure 9-11) is mounted on the outside of the unit and a sensor is mounted inside
the unit on a return bend on the outdoor coil. The sensor is connected to the circuit board in the
control box. In Figure 9-11, the control box is shown mounted on the outside of a wind baffle
attached to the unit. Wind baffles are also an accessory that should be used in locations with high
prevailing winds and where outdoor temperatures of less than 0° F can occur during unit operation. The wind baffle prevents cross currents from causing erratic controller operation. Wind baffles
are also used on heat pumps to prevent the wind from retarding defrost.
Crankcase Heaters – Crankcase heaters (Figure 9-12 and CH, Figure 9-13) warm the compressor crankcase during the off cycle to reduce refrigerant migration and ensure proper compressor
lubrication.
▼ Figure 9-11.
Low-Ambient Temperature Controller
WIND
BAFFLE
LOW-AMBIENT
TEMPERATURE
CONTROLLER
CONDUIT
SENSOR
WIRE
▼ Figure 9-12.
Typical Crankcase Heater
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
Section Topics
9
References
▼ Figure 9-13.
Typical Air Conditioning (Condensing) Unit Wiring Diagram Showing Wiring of Accessories
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Compressor Start Assist Kits – Compressor
start assist kits (Figure 9-14) are used to give
permanent split capacitor (PSC) reciprocating
compressors a boost at start-up. There are two
types of kits: a hard start kit, which consists of
a start capacitor and a start relay (SC and SR,
Figure 9-13) and a positive temperature coefficient (PTC) start thermistor (ST, Figure 9-13).
One or the other device can be used but not
both. Either device may be factory installed or
can be field installed to correct a starting problem. The addition of certain field-installed
accessories or certain installation applications
may require that a start kit be field installed.
Chronic low supply voltage conditions or unexplained compressor tripouts may indicate the
need for a start kit.
Compressor Short Cycle Protector – A compressor time delay (CTD, Figure 9-13) is used
to prevent compressor short cycling. It provides
an approximate five-minute delay after control
power (24 volts) to the compressor contactor
has been interrupted for any reason, including
normal cycling. This device may be either field
or factory wired.
▼ Figure 9-14.
Compressor Start Assist Kits
START RELAY
START CAPACITOR
CAPACITOR/START RELAY
PTC THERMISTOR
PTC START THERMISTOR
Low-Pressure and High-Pressure Switches
– Low-pressure and high-pressure switches
prevent system operation if abnormal pressure
conditions are present. The low-pressure switch
(LPS, Figure 9-13) is an auto-reset switch activated by a drop in refrigerant pressure on the
low side of the refrigerant circuit. If the pressure drops below the setpoint, it turns the
compressor off.
The high-pressure switch (HPS, Figure 9-13)
is an auto-reset switch activated by an increase
in refrigerant pressure on the high side of the
refrigerant circuit. If the pressure rises above
the setpoint, it turns the compressor off.
Liquid Solenoid Valve – The liquid solenoid
valve (Figure 9-15 and LLS, Figure 9-13) is an
electrically operated shutoff valve normally installed in long-line applications to increase
efficiency. It controls liquid refrigerant flow when
the compressor is turned off and on. It prevents
liquid refrigerant migration and maintains a column of liquid refrigerant for the next compressor
on cycle.
9
▼ Figure 9-15.
Typical Liquid Solenoid Valve
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Winter Start Control and Time Delay Relay
Kits – The winter start kit (Figure 9-16) is a
time delay relay that bypasses the low-pressure switch in the outdoor unit for about three
minutes to permit start-up and cooling operation under low load conditions. It should be used
in all units that have a low-pressure switch and/
or a low-ambient controller. The time delay relay is wired across the low-pressure switch.
Evaporator Freeze Protection Thermostat –
The evaporator freeze protection thermostat
stops unit operation if the evaporator or indoor
coil temperature drops below a certain point.
This prevents the coil from freezing up. The temperature sensing bulb is mounted on the
suction/vapor line near the coil. Its contacts are
wired in series with the contactor coil
(Figure 9-17).
9
▼ Figure 9-16.
Winter Start Kit Wiring
T
TDR
C
LPS
LOW-PRESSURE SWITCH
CONTACTOR COIL
TIME DELAY RELAY
RELAY COIL
LPS
C
TDR
T
FACTORY WIRING
FIELD WIRING
▼ Figure 9-17.
Evaporator Freeze Protection Thermostat Wiring
C
LPS
EVAPORATOR
FREEZE PROTECTION
THERMOSTAT
SPLIT SYSTEM INSTALLATION GUIDELINES
The methods for installing split cooling and split heat pump systems are basically the same. The
installation of any system components must always be done as directed in the manufacturer’s
installation instructions and it must comply with the codes and installation practices of the area
where it is to be installed. The installation tasks and the general sequence in which they are
performed are shown in Figure 9-18. A detailed list of required materials and a simple drawing
showing the intended installation should be provided to the installer. Make sure all the required
parts and tools are available before leaving for the job site. If installing a convertible fan coil unit
in a configuration other than that shipped from the factory, reconfigure the fan coil per the installation instructions.
▼ Figure 9-18.
Split System Installation – Tasks and Sequence
Start
Installation
Inventory
Equipment,
Materials,
Tools
Yes
Is
Indoor Unit
a Fan
Coil?
(See Note)
No
Locate and
Level Fan
Coil Unit or
Install and
Level Coil on
Furnace
Plenum
Install
Refrigerant
Line Set
Between
Indoor and
Outdoor
Units
Install
Supply
and
Return Air
Ductwork,
if Needed
Leak Test
and
Evacuate/
Dehydrate
Line Set
and Indoor
Coil
Install
Accessories
and Power
and Control
Components
and Wiring
Install
Condensate
Pump and/
or Drain
Piping
Start Up
System and
Check/
Adjust
Refrigerant
Charge
Complete
Checklist
Configure Fan
Coil for Upflow,
Downflow, or
Horizontal
Installation
as Needed
Check for
Proper
Outdoor
Unit
Location
Check for
Proper
Indoor Unit
Location
Mount
Outdoor
Unit
on Pad
Clean Up
Area and
Present
Equipment
Manuals to
Customer
Install
Accessories
and Power
and Control
Components
and Wiring
Show
Customer How
to Operate
System and
Perform
Simple
Maintenance
Note: This sequence installs the indoor unit first, followed by the installation of the outdoor unit. If desired, the sequence
can be reversed.
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Installing the Indoor Equipment
9
▼ Figure 9-19.
Evaporator Coil Installed on a Furnace
Installing Evaporator/Indoor Coils – Evaporator/indoor coils are made in both cased and
uncased versions. Evaporator coils are normally installed on a fossil fuel heating furnace
(Figure 9-19) as part of an add-on air conditioning or add-on heat pump installation. Add-on
heat pumps are usually done to convert a conventional fossil fuel heating system into a
dual-fuel heating system. Regardless of the
use, the coil installation procedure is basically
the same.
Installing Uncased Coils – Uncased coils are
normally installed in the supply air plenum of
an existing furnace. General guidelines for their
installation are given here.
1. Shut off furnace power. Remove the vent
connector pipe for better access to the furnace plenum, if required.
2. Lay out the pattern on the supply air plenum
for the coil access opening (Figure 9-20).
Refer to the coil installation instructions for
the specific width, height, and mounting dimension requirements.
3. Use aviation shears to cut the opening in the
plenum. BE CAREFUL AROUND THE
SHARP METAL EDGES.
4. Attach support rails or rods to the inside of
the plenum to support the coil per the installation instructions. Fabricate sheet metal
baffles (Figure 9-21) and install them inside
the plenum against the sides. Configure the
baffles and support rails so that when the coil
is inserted, the piping connections are flush
against the coil cover panel and all of the air
will be forced through the coil.
5. Slide the coil through the hole in the plenum
and onto the support rails until it is completely
inside the supply air plenum. Make sure the
coil is level for proper condensate drainage.
6. Carefully measure the location of the coil’s
refrigerant connections and condensate
drain. Make a cover plate out of sheet metal
with holes cut for the refrigerant and condensate lines (Figure 9-22). Install the cover plate
on the plenum and fasten it in place using
sheet metal screws.
7. In high humidity areas, to prevent the possibility of the plenum “sweating” and water
dripping onto the furnace, it may be necessary to wrap the outside of the plenum with
insulation and a vapor barrier. Tape all joints.
8. The coil installation is complete except for
installing the condensate drain piping and the
refrigerant piping. These tasks are covered
later in this section.
▼ Figure 9-20.
Access Hole Cut in Plenum for Uncased
Evaporator Coil
ACCESS HOLE CUT
FOR EVAPORATOR/
INDOOR COIL
➧ WARNING
PLENUM
FURNACE
▼ Figure 9-21.
Support Rails and Sheet Metal Baffles
COIL RESTS
ON RAILS
AND BAFFLES
SUPPORT
RAILS
BAFFLES
▼ Figure 9-22.
Coil Cover Plate
SHEET METAL 1" LARGER
THAN HOLE IN PLENUM
SHEET METAL
1" LARGER
THAN HOLE
IN PLENUM
COIL COVER
PLATE
CUT ON
DOTTED
LINES
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
Section Topics
9
References
Installing Cased Coils – Cased coils ▼ Figure 9-23.
(Figure 9-23) are often used when the coil is
Typical Cased Coil
being installed along with a new furnace. General guidelines for the installation of a cased
coil are given here.
1. Cased coils are designed to fit most furnaces.
If the furnace width is such that the casing
overhangs or underhangs the furnace opening, make and install sheet metal adapters
SUCTION FITTING
(Figure 9-24) per the installation instructions
LIQUID FITTING
to correctly fit the coil case to the furnace.
2. Set the cased coil in place on the furnace
discharge air opening. Make sure it is level
PLUGGED
for proper condensate drainage. Normally,
SECONDARY
DRAIN
the coil does not need to be fastened to the
PRIMARY DRAIN
furnace.
3. Install the supply air plenum and ductwork. Refer to Section 6 for guidelines pertaining to the
installation of duct systems.
4. To prevent the possibility of the plenum “sweating” and water dripping onto the furnace, it may
be necessary to wrap the outside of the plenum with insulation and a vapor barrier. Tape all
joints.
5. Installing a cased coil on a downflow furnace is similar, except the furnace sits on top of the
cased coil and air is discharged down through the coil (Figure 9-25). In many downflow installations, a drip eliminator kit may be required. This kit ensures that the condensate is directed
down and into the drip pan.
6. The coil installation is complete except for installing the condensate drain piping and refrigerant lines. These tasks are covered later in this section.
▼ Figure 9-24.
Adapters Used when Coil Casing Overhangs or
Underhangs the Furnace
▼ Figure 9-25.
Cased Coil Installed on a Downflow Furnace
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Installing a Fan Coil Unit – Fan coils can be
used in upflow, downflow, or horizontal applications. Normally they are shipped from the
factory set up for either upflow or horizontalleft installation, but can easily be modified for
downflow or horizontal-right installations. For
access into attics or crawlspaces, modular units
can usually be disassembled into the coil box
and blower box components (Figure 9-26).
9
▼ Figure 9-26.
Typical Modular Fan Coil Disassembled for
Moving through Limited Openings
Locating the Fan Coil – When possible, centrally locate the fan coil in the building at a
location that allows the air ducts and refrigerant lines to be as short as possible.
Avoid installation above, below, or next to a
bedroom or other area where mechanical noise
is unacceptable. Access for service, appearance, and risk of damage to the unit are other
important considerations.
Installing and Leveling the Fan Coil – Suspended fan coil units should be mounted using
proper rubber or spring vibration-eliminating
hangers to prevent the transmission of noise
through the building structure. The fan coil
should be plumb and level for proper condensate drainage. For a basement installation, it
may be necessary to elevate the fan coil on a
pad or blocks to prevent corrosion. When a
downflow unit with electric heaters is installed
on a combustible floor, it may need to be
mounted on a fireproof downflow base kit per
the instructions provided with the kit.
Installing Air Distribution System Ductwork to the Fan Coil – As part of the pre-installation survey,
the correct sizes of the various pieces of ductwork should have been determined. Refer to Section 6 for general guidelines pertaining to the installation of duct systems.
If required, cut or otherwise prepare an opening on the appropriate side of the fan coil unit for
the return air duct. Place the supply air duct over the flanges on the fan coil unit supply air
opening and fasten with sheet metal screws. Before the return duct is hung and secured to the
fan coil, install the humidifier, electronic air cleaner (EAC), and/or external filter rack, if used.
Use flexible, heat-resistant connectors between the ductwork and the unit to prevent
transmission of unit vibration (Figure 9-27).
Make sure to maintain the distance between
the discharge plenum/ductwork and combus- ▼ Figure 9-27.
Flexible Connectors are Used Between the
tible materials as specified in the installation
Ductwork and Fan Coil to Prevent Vibration
instructions.
Transmission
Installing the Fan Coil Power and Control
Wiring – All wiring to the fan coil unit must comply with local codes and the manufacturer’s
installation instructions. Supply power to the fan
coil unit must use a dedicated line equipped
with a correctly sized fuse or circuit breaker,
with an uninterrupted ground between the fan
coil unit ground and the earth ground in the electrical panel. A disconnect switch should also be
installed at the fan coil. When the power wiring
is completed, leave the power turned off until
you are ready to start up and check out the fan
coil. Install the thermostat and control wiring.
For detailed guidelines on installing power and
control circuit wiring, refer to Section 7.
SUPPLY
MAIN
RETURN
MAIN
FLEX CONNECTOR
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
The installation of power and control wiring
for accessories such as electric heaters, an
electronic air cleaner, or a humidifier should
be wired per the instructions supplied with each
accessory. Figure 9-28 shows the terminals
used for connecting accessories on a typical
fan coil unit control board.
9
▼ Figure 9-28.
Accessory Wiring Terminals on a Typical Fan Coil
Unit Control Board
Installing Condensate Drain Piping – To dispose of condensate from the cooling coil, drain
piping between the coil’s condensate outlet and
an open or vented drain must be installed. A
laundry sink or basement floor drain is commonly used for this purpose.
Coils and fan coils normally have primary and
secondary drain connections. The primary drain
connection is the lower one and must have a
trap installed as close to the unit as possible
(Figure 9-29). Traps must be used to ensure
proper condensate drainage. The secondary
drain is the upper connection and should re- ▼ Figure 9-29.
main plugged when use of a secondary drain
Condensate Drain Connections at the Furnace or
is not required. Use of a secondary drain is
Fan Coil
covered later in this section. Normally, rigid plastic pipe is used for the condensate piping run,
SECONDARY
but clear flexible tubing can be used for some
installations. Refer to Section 5 for the methPRIMARY
ods used to cut and connect rigid plastic pipe.
The diameter of the drain line and fittings
should be the same as the primary (or secondary) outlet to which the pipe is being connected,
typically 3/4 inch. The trap should be positioned
flat against the unit and must have a minimum
depth as specified in the installation instructions,
typically two to three inches. The trap should
be no higher than the bottom of the primary
drain outlet. Once the trap has been made, the
TRAP
remainder of the condensate piping can be run
TO DRAIN
to the drain.
Ideally, a gravity drain should be used. If that is impractical, a condensate pump must be installed to pump the condensate into a suitable drain. Refer to Section 8 for more information about
condensate pumps. Horizontal pipe runs should be pitched toward the drain. Pitch is not a requirement if the drain runs along a level basement floor. Rigid pipe should be supported at least every
ten feet to prevent sagging or strain on the connections. To prevent noise transmission, vibrationabsorbing hangers should be used where the piping contacts the framing of the building.
Figure 9-30 shows an attic installation of a
horizontal fan coil where both the primary and
secondary drain are connected. The primary ▼ Figure 9-30.
Double Condensate Drain Connection
drain is installed with a slight slope toward the
termination. There should be a rise of at least
HORIZONTAL FAN COIL
2-1/4 inches on the outlet side of the trap with
FLEX CONNECTOR
a drop of at least 4-1/2 inches on the entering
RETURN
side of the trap. The secondary drain is piped
PRIMARY
DRAIN
without a trap to a visible location where any
AIR DUCT
SECONDARY
dripping water serves as an early warning to
DRAIN
the customer that the primary drain is plugged.
This is mandatory in an attic installation since
MUST HAVE A DROP
OF AT LEAST
a water leak in the ceiling can cause damage.
MUST HAVE A
41/2 INCHES
RISE OF AT LEAST
A warning sticker should be attached to the sec21/4 INCHES
ondary drain outlet and the customer
IZE
ULL S
encouraged to make a service call if water
RUN BOTH LINES
RUN F
FULL SIZE
drains from it.
CONNECT TO WASTE
PLUMBING SYSTEM
OR OPEN SITE DRAIN
RUN TO VISIBLE LOCATION
AS EARLY WARNING SYSTEM
FOR PLUGGED PRIMARY DRAIN
ATTIC INSTALLATION
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
When installing a coil or fan coil over a finished ceiling or living space, a secondary
condensate pan (Figure 9-31) should be installed under the entire unit to protect against
water damage either from a plugged primary
drain or from water dripping off the outside of
the unit as a result of condensation. Building
codes for many areas mandate the use of a
secondary condensate drain pan. Local codes
should always be consulted for requirements.
The secondary drain pan piping is run, without
a trap, to a visible location. When a secondary
drain pan is used, the coil’s secondary drain
can flow directly into the pan without being
piped.
9
▼ Figure 9-31.
Use of a Secondary Condensate Drain Pan
ATTIC
SECONDARY
CONDENSATE
DRAIN PAN
PRIMARY
DRAIN
SECONDARY COIL
CONNECTION DRAINS
INTO SECONDARY PAN
SECONDARY
DRAIN
Installing the Outdoor Equipment
Locating the Unit – Several important factors must be considered when locating the outdoor
condensing or heat pump unit. Local codes must be checked for special requirements. Many
local codes prohibit locating units in the front yard and/or too close to property lines. The selected
site should also leave the property attractive to the customer. Some guidelines for locating the
outdoor unit are given below. The selected site should be one that achieves the best compromise
among all the factors shown.
• Locate the unit where water, snow, or ice from
▼ Figure 9-32.
the roof or eaves cannot fall directly on the
Carefully Select the Unit Location
unit (Figure 9-32), or where the roof overhang cannot cause recirculation of the air
exhausted from the unit. Do not install outdoor units under decks or porches unless the
clearance dimensions specified by the manuNOT ENOUGH
facturer are met.
CLEARANCE
• Locate the unit near enough to the building
to avoid long tubing runs which can be easily damaged.
• Locate the unit away from bedroom windows
UNIT
or rooms where the operating noise might
be objectionable.
• Locate the unit so that there is enough clearance around the unit for service accessibility
and air movement. Avoid areas where plants
▼ Figure 9-33.
or shrubs can block air movement. Clearance
Locate the Heat Pump where Defrost Water
dimensions are specified in the unit’s instalCannot Run onto Walkways and Freeze
lation instructions.
CONCRETE
• Locate heat pumps so that prevailing winds
PATIO
are prevented from blowing directly across
FROZEN
PUDDLE FROM
the outdoor coil.
DEFROST
• Locate heat pumps where defrost water from
the coil cannot run onto sidewalks, patios,
etc. and freeze (Figure 9-33).
Mounting the Unit – Once the location for the
outdoor unit has been selected, a pad is installed and leveled in preparation for mounting
the unit (Figure 9-34). Pads made of various
materials are available and can be used providing they satisfy local codes. The minimum
dimensions for the mounting pad are specified
in the installation instructions for the unit. Never
mount the outdoor unit on concrete blocks
or wooden skids as they may settle or deteriorate over time.
If installing a heat pump, a 12-inch to 18-inch
bed of gravel or crushed stone extending out
and away from the perimeter of the pad should
be installed to provide for the absorption and
drainage of the unit’s defrost water.
▼ Figure 9-34.
Make Certain the Mounting Pad is Level
➧ CAUTION
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Before mounting the outdoor unit on the pad,
appropriately-sized openings should be made
through the outside wall for the refrigerant lines
and for the power supply wiring to the disconnect.
A condensing unit can be mounted and secured directly to the pad using construction
adhesive (Figure 9-35). When applying the adhesive, care must be taken not to block the drain
holes in the unit’s basepan. If conditions or local codes require that the unit be mechanically
attached to the pad, tiedown bolts should be
fastened through the unit basepan. When
mounting the unit, make sure that all clearances
are maintained as specified in the installation
instructions.
When installing a heat pump in mild climates
where there is little or no snowfall, the unit is
normally installed directly on the pad or using
short legs that raise it above the pad enough to
provide for adequate drainage of defrost water
(Figure 9-36). In locations where the snowfall
is heavy and defrost water will freeze and build
up, the heat pump should be mounted on an
accessory stand that raises the unit high
enough to allow for adequate drainage of the
defrost water and to prevent snow from blocking the coil.
9
▼ Figure 9-35.
Construction Adhesive Being Used to Secure the
Outdoor Unit to the Pad
▼ Figure 9-36.
Elevate Heat Pumps Enough to Allow for
Adequate Drainage of Defrost Water
zzzz
,,,,
yyyy
zzzz
||||
,,,,
yyyy
{{{{
||||
{{{{
z
y
z
yy
,
,
zzzz
,,,,
yyyy
|
|
{
{
zzzz
||||
,,,,
yyyy
{{{{
||||
{{{{
Power and Control Wiring – All wiring to the
outdoor unit must comply with local codes and
the manufacturer’s installation instructions.
Supply power to the outdoor unit must use a
dedicated line equipped with the correct type
and size disconnect and the correct size fuse
or circuit breaker. It must have an uninterrupted
ground between the unit ground lug and the
earth ground in the electrical panel. When the
power wiring is completed, leave the power
turned off until you are ready to start up and
check out the unit.
The control wiring between the indoor and
outdoor units can be installed after the refrigerant lines are run. The control wires running
between the units are commonly taped to the
refrigerant lines and exit the building through
the same hole as the refrigerant lines. For detailed guidelines on installing power and control
circuit wiring, refer to Section 7.
GRAVEL
BED
OPTIONAL
LEGS
MILD CLIMATE – LIGHT OR NO SNOWFALL
GRAVEL
BED
ACCESSORY
SNOW STAND
(REQUIRED)
SNOW-BELT AREA
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Installing Refrigerant Tubing Lines
Installing the Correct Metering Device – Before connecting the refrigerant lines, it is
important to make sure that the metering device for the indoor unit is the size and/or type
specified in the installation instructions for the
indoor unit. If the coil uses a piston-type metering device, check the size shown on the indoor
unit rating plate to see if it is the same piston
size shipped with the outdoor unit and as shown
on the outdoor unit rating plate (Figure 9-37). If
it does not match, replace the indoor piston with
one shipped with the outdoor unit.
Installing the Refrigerant Lines – The refrigerant lines used to connect the outdoor and
indoor units can be a manufactured tubing kit
(line set) or they can be field-supplied and assembled from refrigerant grade (ACR) tubing
of the correct size. Line sets (Figure 9-38) come
in various lengths and tubing diameters. Line
sets may have no fittings on the ends, compression or flare fittings, or may come
precharged with refrigerant and have quick
connects on the ends. The procedures for working with line sets and/or ACR grade soft and
hard copper tubing are described in detail in
Section 4. If field-supplied tubing is used, the
vapor line (suction line in cooling-only systems)
must be adequately insulated. The remainder
of this section will describe the installation of a
line set. Field-supplied tubing should be installed in a similar manner. The sizes of the
liquid and vapor line tubing used with a split
system are specified in the installation instructions for the outdoor unit and apply to tubing
runs up to 50 feet. Tubing runs greater than 50
feet are considered long-line applications. Before installing a long-line system, you should
always follow the recommendations given in the
manufacturer’s Guidelines for Split System
Long-Line Applications or similar document
available from your distributer.
Running the refrigerant lines between units
(Figure 9-39) is best done by two people and is
accomplished as follows:
1. Remove the line set from the shipping carton. The liquid line is the smaller diameter
uninsulated line; the vapor line is larger and
is insulated with black foam rubber. Do not
remove the rubber plugs from the tubing
ends at this time.
2. One at a time, unroll and straighten out both
lines and tape the lines together at convenient intervals. One person can unroll while
the other holds the tubing. Be careful not to
collapse the tubing and avoid bends that can
kink the tubing.
3. Being careful not to cut the insulation, feed
the taped bundle of tubing through the hole
in the outside wall until enough tubing is available to easily reach the refrigerant
connections on the outdoor unit and indoor
unit. Leave enough slack between the structure and the unit to absorb vibration. Seal
the opening in the wall with caulk.
9
▼ Figure 9-37.
Indoor Coil Piston Size Should Match the Piston
Size Listed on the Outdoor Unit Rating Plate
▼ Figure 9-38.
Typical Line Set
INSULATED SUCTION LINE
LIQUID LINE
PROTECTIVE
CAPS
▼ Figure 9-39.
Installing Refrigerant Lines Between Units
➧ CAUTION
PIPING INSTALLATION
QUICK NOTE
Many installers tape the multiconductor control wire between the
indoor and outdoor units to the
refrigerant tubing.
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
9
References
Section Topics
QUICK NOTE
Do not bury more than 36 inches of refrigerant tubing in the ground. If more than 36 inches of tubing
is buried, refrigerant can migrate to the cooler buried section during extended periods of unit shutdown, causing refrigerant slugging and possible compressor damage at start-up. If any tubing is
buried, at least six inches of vertical rise should be provided at the service valve. Also, the buried line
set should be run inside a chase or conduit. It is also recommended that a crankcase heater be
installed in the unit.
4. Run the refrigerant lines between the units
as directly as possible by avoiding unnecessary turns and bends. Use tubing benders to
make any sharp bends or cut the line sets
and use sweat elbows, if required.
Support the lines every six to ten feet, and
within two feet of bends. Avoid direct contact
of the line set with water pipes and/or
ductwork. Wire or straps used to support the
tubing should contain foam rubber or similar
insulation to isolate the tubing from the building structure (Figure 9-40). This prevents
unwanted noise transmission.
▼ Figure 9-40.
Typical Refrigerant Tubing Support
Vapor Line Considerations – The location of
the indoor coil relative to the compressor in the
outdoor unit must also be considered when running the refrigerant tubing. When the indoor coil
is located above the compressor, the vapor line
should loop up to the height of the indoor coil
(Figure 9-41). This helps to prevent liquid refrigerant from migrating to the compressor
during the off cycle.
When the indoor coil and compressor are at
the same level, the vapor line should pitch toward the compressor (Figure 9-42) with no sags
or dips in straight runs.
When the indoor coil is below the compressor, oil must be returned to the compressor via
a vertical riser in the vapor line (Figure 9-43).
An oil trap should be provided at the entrance
to the riser to collect and feed back small
amounts of oil to the compressor to prevent
compressor damage. The horizontal run to the
compressor should also be pitched toward the
compressor.
▼ Figure 9-41.
Vapor Line with Indoor Coil Above the Outdoor Unit
Connecting Refrigerant Lines to the Indoor
and Outdoor Units – Brazing and mechanical
fittings are two methods commonly used to connect refrigerant lines to split system
components. To prevent contamination and
moisture from entering the system, do not remove protective dust covers and/or plugs from
the equipment or tubing until just before making the actual connection.
HANGER
TUBING
FLOOR
JOIST
INDOOR
COIL
OUTDOOR
UNIT
INDOOR
COIL
OUTDOOR
UNIT
▼ Figure 9-42.
Vapor Line with Indoor Coil at the Same Level as
the Outdoor Unit
10'
1"
INDOOR
COIL
OUTDOOR
UNIT
INDOOR
COIL
OUTDOOR
UNIT
1"/10'
PITCH TO COMPRESSOR
▼ Figure 9-43.
Vapor Line with Indoor Coil Below Outdoor Unit
1"/10'
PITCH TO
COMPRESSOR
OUTDOOR
UNIT
SUCTION
RISER
INDOOR
COIL
OIL
TRAP
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
References
Section Topics
Brazing the Connections – The outdoor unit
normally comes from the factory with the operating charge of refrigerant sealed in the outdoor
unit by the service valves. Be sure to check
local code requirements pertaining to the use
of silver bearing or non-silver bearing brazing
material. Brazing is covered in detail in Section
5. Connections are brazed at the outdoor and
indoor units as follows:
1. At the outdoor unit, slide back the insulation
and clean the exposed vapor tubing.
2. Remove the plugs from the end of the tubing
and the vapor service valve port, then insert
the end of the tubing into the port until it bottoms. Braze the joint.
Make sure to wrap the service valve with a
wet cloth to avoid damaging the valve while
brazing. A brazing shield should also be used
to prevent damage to any painted surface.
Inspect the joint when done.
3. Good practice is to install a filter-drier in the
liquid line. For heat pump split systems, make
sure to use a bi-directional heat pump filterdrier. For cooling systems, make sure that
the arrow on the filter-drier points away from
the outdoor unit and toward the indoor evaporator coil (Figure 9-44).
Some heat pumps are shipped with a flare
adapter and liquid line strainer (Figure 9-45).
They also include a flow direction sticker.
These must be installed on the liquid service
valve after which the liquid line is brazed to
the flare adapter.
4. At the indoor coil or fan coil, remove the plugs
when ready to make the connections, then
braze the vapor and liquid lines to the coil.
Inspect the joints when done. Some coils are
also shipped with a flare adapter, liquid line
strainer, and flow direction sticker as described above for heat pump units.
5. After the brazing is completed and the joints
inspected, seal the openings around the coil
access plate to prevent air leakage.
9
▼ Figure 9-44.
Install a Filter-Drier at the Outdoor Unit Liquid
Line Service Valve
TO LIQUID
LINE SERVICE
VALVE
LIQUID LINE
FLOW
▼ Figure 9-45.
Flare Adapter Installed at Heat Pump Liquid Line
Service Valve
Making Mechanical Connections – Outdoor and indoor units can have several different kinds of
mechanical connections. Connecting refrigerant lines with mechanical-type connectors should
always be done as directed in the installation instructions. Compression fittings that use a ferrule
and locknut are commonly used.
To make a connection using a ferrule and ▼ Figure 9-46.
Ferrule and Locknut Compression Fittings
locknut-type compression fitting, proceed as follows:
1. Cut the tubing to the correct length, making
sure the tube ends are square. The tubing
should be clean, round, and free of nicks and/
or burrs.
2. Slide the locknut onto the tubing, followed
by the ferrule (Figure 9-46).
3. Lubricate the ferrule and the threads of the
mating valve or adapter threads with a few
drops of refrigerant oil.
4. Insert the end of the tubing into the mating
valve or adapter until it bottoms. Push the
ferrule in place and tighten the locknut until
an increase in torque is felt.
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
9
References
Section Topics
QUICK NOTE
For detailed information and procedures for methods of leak detection and evacuation, refer to
Service Procedures SP-1 and SP-3, respectively, in the companion HVAC Servicing Procedures
handbook.
5. Mark the nut and tubing, then tighten the nut
1-1/2 turns from the mark (Figure 9-46). Be
sure to keep the tubing bottomed in the valve
or adapter while tightening the nut. A backup
wrench should be used on the hex part of
the valve or adapter while tightening.
Line sets precharged with refrigerant are
made with specially-designed couplings at the
ends of the tubing that must match the fittings
provided on the indoor and outdoor units. Typically, the unit fitting contains a diaphragm that
seals refrigerant within the line. As the fittings
are connected, a knife blade in the fitting cuts
through the diaphragm of both sets of fittings.
When completely coupled, the diaphragm is cut
through and pushed out of the way by the knife
edge, allowing the refrigerant to flow freely.
Precharged line sets do not have to be purged
or evacuated before or after a connection is
made. There are usually no service valves on
units equipped with these types of fittings.
▼ Figure 9-47.
Electronic Leak Detector and Bubble Solution
Used to Locate Leaks
BEEP
BEEP
LEAK
DETECTOR
SOLUTION
Leak Testing and Evacuating the Refrigerant Lines – Once the refrigerant lines are connected
between the indoor and outdoor units, they must be checked for leaks and evacuated. The outdoor unit is shipped from the factory with a complete charge and with its service valves closed
(front-seated). Do not open (back-seat) the outdoor unit’s service valves until after the refrigerant lines and indoor coil have been evacuated and leak tested. With the outdoor unit
service valves back-seated, the refrigerant lines and indoor coil are isolated from the outdoor unit
and can be accessed for leak testing and evacuation through the service ports on the service
valves.
To perform a leak test, pressurize the lines ▼ Figure 9-48.
Vacuum Pump and Vacuum Gauge Used to
and indoor coil with nitrogen and a trace of
Evacuate the Refrigerant Lines and Indoor Coil
HCFC-22 (R-22) refrigerant. Then, use a bubble
solution, electronic leak detector, or both to loREFRIGERANT
cate any leaks (Figure 9-47). When leak testing
LINES TO
VAPOR/SUCTION
is completed, the mixture of nitrogen and trace
INDOOR
LINE (FRONTCOIL
SEATED)
refrigerant can be vented to the atmosphere.
Following this, the lines must be evacuated.
LIQUID LINE
SERVICE VALVE
(FRONT-SEATED)
THERMISTOR
VACUUM GAUGE
GAUGE PORT
25000
2500
1300
1000
700
400
275
200
100
50
MICRONS
ON
THERMISTOR
VACUUM GAUGE
OFF
GAUGE
MANIFOLD
SET
VACUUM PUMP
SPLIT SYSTEM INSTALLATION 9
Table of Contents
Map
Section Topics
References
Leak testing can also be performed as part of the refrigerant line evacuation process. Evacuate
the refrigerant lines and indoor coil to 500 microns or less using a good vacuum pump and
accurate vacuum gauge (Figure 9-48). If the lines and coil are free of leaks, the reading on the
vacuum gauge will not rise significantly when the vacuum pump is shut off.
If the vacuum gauge shows a pressure rise and the pressure continues to rise without leveling
off, a leak exists and must be repaired. If it shows a pressure rise but levels off between 1,000 and
2,000 microns, this indicates that the lines and coil are leak tight, but are too wet. A
constant reading on the vacuum gauge of between 500 and 1,000 microns indicates that the lines
and coil are leak tight and dry.
When the evacuation is complete, remove the vacuum pump and vacuum gauge, but leave the
gauge manifold connected to the service ports with both service valves front-seated in preparation for start-up and checkout.
Start-Up and Checkout
The system must always be started up and fully
checked out per the installation instructions before the technician leaves the site. Start up the
cooling or heat pump system and check out the
cooling mode as follows:
1. If equipped with a crankcase heater, energize the heater a minimum of 24 hours before
starting the unit. To energize the heater only,
set the thermostat to OFF and turn on the
power to the outdoor unit.
2. Remove the valve stem caps from the service valves (Figure 9-49) and turn the valve
stems fully counterclockwise to open the
valves, allowing the refrigerant into the entire system.
3. Turn on the power to the indoor fan coil or
furnace and the outdoor unit.
4. Set the room thermostat to COOL and the
fan switch to ON or AUTO. Operate the system for 30 minutes to allow system pressures
and temperatures to stabilize.
During this time, make general component
and operational checks and clean up the
area. At the indoor unit, check the condensate drain. On a humid day, condensate
water should run from the drain after a short
period of time.
▼ Figure 9-49.
Typical Service Valves
QUICK NOTE
If installing a split cooling system and the outdoor temperature is below 55° F, wait for a warmer day
before starting and checking out the system.
While performing the various start-up tasks, the Residential Split System Cooling Installation
and Start-Up Checklist located on page 159 of this book should be used to check off each item
when completed. Use of a checklist ensures that an organized and consistent procedure is
followed and that no area of the installation or checkout is overlooked.
SPLIT SYSTEM INSTALLATION 9
Table of Contents
Map
Section Topics
References
QUICK NOTE
For detailed information and procedures pertaining to charging refrigerants, refer to Service Procedure SP-4 in the companion HVAC Servicing Procedures handbook.
5. If necessary, check and/or adjust the system
refrigerant charge. Use the superheat
method for systems equipped with fixed-orifice metering devices and use the subcooling
method for systems equipped with a thermostatic expansion valve (TXV) metering
device. Note that factory-charged units often need a charge adjustment to compensate
for longer-than-standard refrigerant line
lengths and/or the use of a filter-drier or other
accessory. BE CAREFUL WHEN CONNECTING THE GAUGE MANIFOLD SET
TO SERVICE VALVES NOT EQUIPPED
WITH SCHRADER VALVES AT THE
GAUGE PORT. TO PREVENT INJURY AND
REFRIGERANT LEAKS, MAKE SURE
THAT THE VALVES ARE FULLY BACKSEATED BEFORE REMOVING THE
GAUGE PORT CAPS.
A charging aid called a Required Superheat/Subcooling Calculator (Figure 9-50) can
be used to check the charge in systems that
use HCFC-22 refrigerant. A similar calculator is available for HFC-410A. Complete
instructions are printed on the calculator.
6. Check the airflow across the indoor coil in
the cooling mode. For proper operation, the
furnace or fan coil blower should be moving
from 400 to 450 CFM of air across the coil
for each ton of capacity. If required, adjust
the furnace or fan coil blower speed per the
manufacturer’s instructions to obtain the
proper airflow.
A quick check of airflow can be made using the “Proper Airflow Range” section
(Figure 9-50) of the Required Superheat/
Subcooling Calculator previously described.
Complete instructions are printed on the calculator.
➧ WARNING
▼ Figure 9-50.
Required Superheat/Subcooling Calculator
QUICK NOTE
For detailed information and procedures for measuring airflow, refer to Service Procedures SP-14
through SP-17 in the companion HVAC Servicing Procedures handbook.
SPLIT SYSTEM INSTALLATION
Table of Contents
Map
Section Topics
7. If operating a split system with a furnace, set
the thermostat to HEAT and check furnace
operation and temperature rise as previously
described in Section 8. If operating a split
heat pump system, check the charge in the
heating mode by following the procedure on
the heating check chart located on the unit
or check the charge in the cooling mode using the superheat or subcooling method. Also
measure the temperature rise and airflow in
the fan coil unit.
8. Disconnect the gauge manifold set and other
test equipment from the outdoor and indoor
units. BE CAREFUL WHEN DISCONNECTING THE GAUGE MANIFOLD SET FROM
SERVICE VALVES NOT EQUIPPED WITH
SCHRADER VALVES AT THE GAUGE
PORT. TO PREVENT INJURY, MAKE SURE
THAT THE VALVES ARE FULLY BACKSEATED BEFORE DISCONNECTING THE
MANIFOLD SET HOSES. Replace and
tighten all valve stem and gauge port caps.
References
➧ WARNING
Final Checks, Adjustments, and
Tasks
With the units operational, the following checks
should be done to complete the installation.
• Check for correct operation of accessories
such as an electronic air cleaner or humidifier, if installed.
• Check the outdoor unit, fan coil/furnace, and
ductwork for any unusual noise or vibration.
• Adjust the balancing dampers in each branch
run of duct for correct operation (refer to
Section 6).
• Clean up the work area when done.
Before leaving the job, explain the operation
of the complete system to the customer
(Figure 9-51). Describe how the system operates and run the system through a complete
cycle so the customer can see and hear the
normally operating system. If installed, demonstrate the operation of accessories. After the
demonstration, present the customer with the
owner’s operating and service manuals and
warranty.
9
▼ Figure 9-51.
Explain the Operation of the System to
the Customer
PACKAGED UNIT INSTALLATION
10
▼ PACKAGED UNIT INSTALLATIONN
SECTION 10
INTRODUCTION
This section provides guidelines for the installation of packaged cooling/heating and heat pump
systems and related accessories. It is not intended to teach refrigeration or air distribution system
theory; instead, it describes the different kinds of packaged units and the methods used to install
them. This section presumes that the proper type of equipment and related accessories have
been selected and purchased by a qualified engineer or salesperson based on a survey of
the job.
PACKAGED UNIT MENU
Packaged Systems
PTAC Units
PAC Units
YAC Units
Heat Pump Units
Accessories
Outdoor Air Damper Kits
Economizer
Packaged Unit Installation Guidelines
Initial Preparation
Locating the Unit
Preparing Slab or Rooftop Sites for Installation
Rigging and Placing the Unit
Installing Air Distribution System Ductwork
Condensate Drain Piping
Installing Vent Hood and Gas Piping (YAC)
Power and Control Wiring
Start-Up and Checkout
Final Checks, Adjustments, and Tasks
PACKAGED UNIT INSTALLATION
Table of Contents
Map
Section Topics
10
References
PACKAGED SYSTEMS
Packaged systems contain all the components for cooling, heating, or both in one factory-built
package. For residential and light commercial applications, they fall into four categories:
• Packaged terminal air conditioners (PTACs)
• Packaged air conditioners (PACs)
• Year-round air conditioners (YACs)
• Heat pumps
PTAC Units
Packaged terminal air conditioners or PTACs
(Figure 10-1) are typically used to cool one room
such as a motel room. Both heat pumps and
models with electric resistance heat are available. PTAC units slide into a wall sleeve that is
built into the exterior wall of the building. Installation of the unit itself normally involves sliding
it into its sleeve and plugging its power cord
into an electrical outlet.
▼ Figure 10-1.
PTAC Unit and Wall Sleeve
PAC Units
Packaged air conditioners or PACs (Figure
10-2) are commonly used for both residential
and light commercial applications. PACs can
provide cooling only or they can provide both
cooling and heating when equipped with electric resistance heaters (electric cooling/electric
heating units).
PACs are usually installed at ground level on
a slab or on rooftops (Figure 10-3). Factorysupplied roof curbs are used for installation on
flat and pitched roofs. Stands are sometimes
used where appropriate. When the unit is installed on a roof curb, gaskets are placed on
the curb to seal out rain before the unit is rigged
into place. The discharge airflow orientation
(horizontal or vertical) will determine how the
supply and return ductwork is connected.
Round or rectangular supply and return duct
flanges on the unit provide for connection to
flexible or standard metal air ducts.
▼ Figure 10-2.
Typical Packaged Unit
YAC Units
The year-round air conditioner (YAC) unit provides both cooling and heating. It differs from a
PAC in that its heating capability is provided by
a natural or LP gas heating section (gas heating/electric cooling). All the other features
described above for PACs also apply to YACs.
Heat Pump Units
Heat pump packaged units provide both heating and cooling. As a heat pump, they extract
heat from the outdoor air and move it into the
conditioned space. This heat can be supplemented by electric resistance heat when
necessary. For cooling operation, the heat
pump works like a conventional air conditioner.
All the other features described for PACs also
apply to packaged heat pumps.
▼ Figure 10-3.
Ground Level and Rooftop Mounting of
Packaged Units
PACKAGED UNIT INSTALLATION
Table of Contents
Map
References
Section Topics
ACCESSORIES
Many of the accessories previously described
in Sections 8 and 9 for use with furnaces or
split system outdoor units are also used with
packaged units. All such accessories should be
installed as directed in the accessory installation instructions.
Depending on the application, the accessories can be either factory or field installed. These
accessories include:
• Natural gas-to-propane conversion kit
• Low-ambient temperature controller
• Electric resistance heaters (Figure 10-4)
• Crankcase heater
• Compressor start assist kit
• Compressor short cycle protector
• High-pressure and low-pressure switches
• Outdoor air damper kits and economizers
This section focuses on outdoor air damper
kits and economizers, both commonly used with
packaged units.
10
▼ Figure 10-4.
Electric Resistance Heaters Mounted on a
Blower Housing
▼ Figure 10-5.
Typical Outdoor Air Damper Kit
Outdoor Air Damper Kits
Manual and two-position outdoor air damper
kits provide year-round ventilation (Figure
10-5). The manual damper is adjusted to allow
adequate outdoor ventilation airflow in the building to maintain good indoor air quality and
negative pressure inside the unit. Typically, the
outdoor air ventilation rate should be about 15
to 20 CFM per person. The two-position outdoor air damper kit is similar to a manual
damper and is also adjusted to provide the airflow needed to maintain good indoor air quality
and negative pressure. It allows fresh outside
air to enter the building whenever the unit indoor fan is energized.
Economizer
An economizer is an automatically-controlled
damper system that reduces system operating
cost for cooling operation and provides for adequate building ventilation air during all modes
of operation. It uses cool outdoor air to satisfy
the cooling load (free cooling) whenever the
outside air temperature is low enough. If the
outdoor air alone cannot satisfy the cooling requirements, economizer cooling can be used
in conjunction with air conditioner (compressor)
operation.
There are many variations of economizers.
Figure 10-6 shows a typical economizer. A basic economizer uses an outdoor air thermostat
(OAT) to sense the outdoor dry bulb (sensible
heat) air temperature. More efficient units use
an enthalpy control (EC) instead of a thermostat to measure both the temperature and
humidity (latent heat) of the outdoor air. The
OAT or EC is normally installed on the inside of
the ecomonizer hood assembly (Figure 10-7).
Some systems use a second enthalpy control
called a differential enthalphy control mounted
in the return air duct. These systems compare
the temperatures and humidities of both the
outdoor air and indoor return air.
▼ Figure 10-6.
Basic Economizer System
ROOM
THERMOSTAT
SUPPLY AIR
THERMOSTAT
(SAT)
INDOOR
COIL
OUTDOOR AIR
THERMOSTAT (OAT)
OR ENTHALPY
CONTROL (EC)
(OPTIONAL)
MIXED AIR
OUTDOOR
AIR
ECONOMIZER
CONTROL
MODULE
DAMPER
ACTUATOR
ENTHALPY
SENSOR
(OPTIONAL)
RETURN
AIR
▼ Figure 10-7.
Typical Outdoor Thermostat/Enthalpy Control
Installed Location
OUTDOOR AIR
THERMOSTAT
OR ACCESSORY
ENTHALPY
CONTROL
ENTHALPY CONTROL L
PACKAGED UNIT INSTALLATION
Table of Contents
Map
10
References
Section Topics
After sensing the outdoor and/or indoor temperatures and humidity, control voltages from the
OAT or EC sensors, along with control voltages from the room thermostat and supply air thermostat (Figure 10-6) cause the economizer control unit to position the economizer damper to admit
the required amount of air for mixing into the building’s air distribution system. These control
voltages also tell the damper to close if the outside air is getting too warm or humid for effective
free cooling. The sequence of economizer operation and the procedure for setting the economizer controls are normally included in the installation instructions for the economizer.
PACKAGED UNIT INSTALLATION GUIDELINES
The methods for installing PAC, YAC, and heat pump systems are basically the same. The installation of a packaged unit must always be done as directed in the manufacturer’s installation
instructions and must also comply with all codes and installation practices of the area where it is
to be installed. The tasks for installing packaged units and the general sequence in which they
are performed are shown in Figure 10-8.
▼ Figure 10-8.
Packaged Unit Installation – Tasks and Sequence
Start
Installation
Install
Supply
and
Return Air
Ductwork
Inventory
Equipment,
Materials,
Tools
Install Optional
Accessories,
(e.g., Dampers,
Economizer,
etc.)
Configure
Unit for
Vertical or
Horizontal
Discharge
if Needed
Install and
Prime
Condensate
Trap and
Drain Piping
Check
Location
Yes
Is Unit a YAC?
Install Slab
or
Roof Curb
Rig Unit
and Install
on Slab or
Roof Curb
Install
Gas Piping
and
Hood
Vent
Purge and
Leak Test
Gas Piping
No
Install
Power and
Control
Components
and Wiring
Adjust YAC
Unit Gas
Input Rate
Check Unit
Cooling
Operation
and
Refrigerant
Charge
Check
Temperature
Rise and
Adjust
Thermostat
Heat
Anticipator
Yes
Yes
Is Unit a PAC?
No
Is Unit a
Heat Pump?
No
Check
System
Cooling and
Heating
Airflow
Complete
Checklist
Check
Heat Pump
Heating
Mode
Operation
and Defrost
Check
Electric
Resistance
Heaters
(Optional)
Clean Up
Area and
Present
Equipment
Manuals to
Customer
Show
Customer How
to Operate
System and
Perform
Simple
Maintenance
PACKAGED UNIT INSTALLATION
Table of Contents
Map
10
References
Section Topics
QUICK NOTE
Most packaged units have two sets of duct openings to allow for the option of either rooftop or
ground-level installation. It is sometimes necessary to buy or fabricate covers for the unused openings
(see Figure 10-9).
Initial Preparation
A detailed list of required materials and a simple
drawing showing the intended installation
should be provided to the installer. Always make
sure all the required parts and tools are available before leaving for the job site. Configure
the unit for proper supply and return airflow orientation (if required) per the installation
instructions before leaving the shop
(Figure 10-9).
▼ Figure 10-9.
Reconfiguring a Unit for Downflow Orientation
ADD SIDE PANELS
Locating the Unit
Several important factors must be considered
when locating the unit. Local codes must be
checked for special requirements. Some guidelines for locating the unit are given below. The
selected site should be one that achieves the
best compromise among all the factors shown.
REMOVE BOTTOM PANELS
All Units –
• Locate the unit so that the required minimum clearances are maintained from combustible
materials, air intakes, adjacent buildings or walkways, and for service accessibility and air
movement. Clearance dimensions are specified in the unit’s installation instructions.
• Locate heat pump units so that prevailing winds are prevented from blowing directly across the
outdoor coil. Install a wind baffle, if necessary.
• Locate YACs where downdrafts or prevailing winds cannot affect venting of combustion
byproducts.
Slab-Mounted Units –
• Locate the unit where water, snow, or ice from the roof or eaves cannot fall directly on the unit,
or where the roof overhang cannot cause recirculation of the unit exhaust air.
• Locate the unit away from windows or rooms where sound or air discharge might be
objectionable.
• Locate the unit so that the outdoor duct runs connecting to the unit are short.
• Locate heat pump units where defrost water from the coil cannot run onto sidewalks, patios,
etc. and freeze.
Roof-Mounted Units –
• If installed on a flat roof, be sure the unit is at least four inches above the highest water level
expected.
• Locate the unit away from building exhaust vents or other sources of contaminated air.
Preparing Slab or Rooftop Sites
for Installation
Slab Mount – A unit installed at ground level
(Figure 10-10) should always be mounted on a
slab or pad constructed as specified in the unit
installation instructions. Typically, the slab is
made of concrete, but pre-fabricated pads are
also available. Position the unit to prevent grass
or shrubs from obstructing airflow.
▼ Figure 10-10.
Slab-Mounted Unit
PACKAGED UNIT INSTALLATION
Table of Contents
Map
References
Section Topics
For a heat pump unit, install a bed of gravel
or crushed stone extending out and away from
the perimeter of the slab to provide for the absorption and drainage of defrost water. If
installed in an area of heavy snowfall, a frame
or snow stand should be used (Figure 10-11)
to support the unit at a height of 12 to 24 inches
above the slab.
Roof Mount – A roof-mounted unit (Figure
10-12) is installed using a curb kit designed to
mount the unit level, regardless of the pitch of
the roof. The curb used is determined by the
type and pitch of the roof and the model of
equipment being installed.
For vertical (downflow) units, the building
supply and return air ducts must be positioned
to match the openings in the curb, which should
line up with the supply and return openings in
the unit. Curbs are usually installed by other
trades during the building’s construction and
should conform to the standards in the unit’s
installation instructions (Figure 10-13). The seal
strip gasketing supplied with the curb must be
placed on all horizontal surfaces of the curb,
as directed in the instructions, to provide a watertight seal and prevent air leaks once the unit
is installed. For many vertical applications, the
supply and return air ducts are fastened to the
roof curb rather than the unit.
10
▼ Figure 10-11.
Heat Pump Snow Stand
SNOW STAND
▼ Figure 10-12.
Rooftop Unit – Vertical Application
Rigging and Placing the Unit
Rigging should always be performed by
qualified riggers and as directed in the unit
installation instructions. Refer to Section 4
for detailed information on rigging procedures
and equipment. Once the unit is mounted on
the slab or curb, install accessories such as an
economizer or damper kit, if used.
▼ Figure 10-13.
Typical Roof Curb Construction Details
RETURN AIR
OPENING
SUPPLY AIR
OPENING
SUPPLY
AIR
RETURN
AIR
UNIT
SEAL STRIP
(SUPPLIED
WITH CURB)
CANT STRIP
(FIELD SUPPLIED)
COUNTER FLASHING
(FIELD SUPPLIED)
ROOFING FELT
(FIELD SUPPLIED)
ROOFING MATERIAL
(FIELD SUPPLIED)
RIGID INSULATION
(FIELD SUPPLIED)
PACKAGED UNIT INSTALLATION
Table of Contents
Map
References
Section Topics
Installing Air Distribution System
Ductwork
The correct sizes and dimensions of the
ductwork should have been determined during
the pre-installation survey. Refer to Section 6
for guidelines pertaining to the installation of
duct systems. All units should have field-supplied filters or an accessory filter rack installed
in the return air side. For horizontal discharge
units, the supply and return plenums can be
connected to the unit with metal or flexible ducts
(Figure 10-14). For proper airflow, flexible
ductwork must be positioned in a way that eliminates sharp bends or dips. For PAC/heat pump
units with electric resistance heaters, make sure
to observe the required minimum clearances
from combustible materials. Insulate and weatherproof all exposed ductwork. Secure all ducts
to the building structure. Flash, weatherproof,
and vibration-isolate duct openings in the wall
or roof according to good construction practices.
▼ Figure 10-14.
Flexible Air Ducts Connected for Horizontal
Discharge
Condensate Drain Piping
Condensate piping must comply with local
codes and restrictions and with the installation
instructions. Slab-mounted units should be
drained into a gravel apron. Where codes permit, the condensate water from rooftop units
can be drained directly onto the roof. If not, the
condensate must be piped to a suitable drain
(Figure 10-15). The pipe should be the same
diameter as the unit’s drain outlet throughout
the length of the run. Pitch the drain pipe downward at least one inch per ten feet of horizontal
run.
For both slab- and roof-mounted units, a condensate trap must be installed at the unit’s
condensate drain to ensure proper drainage.
Make sure that the outlet of the trap is at least
4-1/4 inches lower than the unit condensate
connection to prevent the condensate pan from
overflowing. Once the trap is installed, prime it
with water.
10
▼ Figure 10-15.
Rooftop Unit Condensate Drain Piping
TRAP
DRAIN PIPE
PACKAGED UNIT INSTALLATION
Table of Contents
Map
References
Section Topics
Installing Vent Hood and Gas
Piping (YAC)
YAC units are shipped with a vent hood (flue
hood) that must be installed over the unit’s flue
outlet per the installation instructions (Figure
10-16). A gas supply line must be run to the
heating section of the unit. All gas piping must
comply with local codes and the manufacturer’s
installation instructions. To install the gas line,
run a correctly-sized black iron pipe to the unit.
Be sure that it is adequately supported and that
it has a drip leg just outside the unit cabinet
and a manual gas shutoff valve near the unit
(Figure 10-17). Install a ground joint union in
the pipe to the main gas valve. Once the gas
piping is installed, turn the gas on and purge
the line of air by loosening the union slightly
until an odor of gas is noticed, then re-tighten
it. Following this, check all joints for leaks using a leak detecting solution. For detailed
procedures used to correctly size gas pipe, refer to Section 8 and to the National Fuel Gas
Code. For information about cutting, threading,
and assembling gas pipe, refer to Section 5.
10
▼ Figure 10-16.
Vent Hood Installed on a YAC Unit
VENT HOOD
▼ Figure 10-17.
Gas Line Installation to a Rooftop YAC Unit
UNION
SHUTOFF
VALVE
Power and Control Wiring
All wiring must comply with local codes and the
manufacturer’s installation instructions. For detailed guidelines for installing power and control
circuit wiring, refer to Section 7.
Supply power to the unit must use a dedicated line equipped with a correctly-sized fuse
or circuit breaker with a dedicated ground wire
attached to the unit ground and to the earth
ground in the electrical panel. A disconnect
switch must also be installed at the unit. Note
that codes in some areas may require that a
separate disconnect be installed for electric
heaters. When the power wiring is completed,
leave the power turned off until you are ready
to start up and check out the unit. Following
this, install the room thermostat and control
wiring.
DRIP LEG
Start-Up and Checkout
The unit must always be started up and fully
checked out per the installation instructions before the technician leaves the site.
Cooling Checks - All Units – Start up and
check out the cooling mode as follows:
1. If equipped with a crankcase heater, energize the heater for a minimum of 24 hours
before starting the unit.
2. Prior to start-up, prime the condensate drain
and trap. Turn on power to the unit.
3. Set the room thermostat to COOL, the fan
switch to ON or AUTO, and the thermostat
setpoint below room temperature. Operate
the system for 30 minutes to allow system
pressures and temperatures to stabilize.
QUICK NOTE
If the outdoor temperature is below 55°
F, wait for a warmer day before operating the unit in the cooling mode.
PACKAGED UNIT INSTALLATION
Table of Contents
Map
Section Topics
10
References
QUICK NOTE
Packaged units come shipped from the factory fully charged and tested, and should require no
charge adjustment. If the charge is incorrect, check the unit for leaks. Refer to Service Procedure
SP-1 in the companion HVAC Servicing Procedures handbook for detailed information and procedures for leak detection. Refer to Service Procedure
SP-4 for information and procedures pertaining to refrigerant charging.
During this time, make component and operational checks and clean up the area. Check the
condensate drain operation.
While performing the various start-up tasks, the Packaged Unit Installation and Start-Up Checklist located on page 160 of this book should be used to check off each item when completed.
4. Check unit pressures and temperatures to determine if the charge is correct. If necessary,
adjust the charge using the procedure shown on the unit charging label.
Heating Check - PAC with Electric Resistance Heating Elements – Check out the heating
mode as follows:
1. Set the room thermostat to HEAT, the fan switch to ON or AUTO, and the thermostat setpoint
above room temperature or jumper the thermostat R and W terminals.
2. Check that all heating elements are active, and make sure that the indoor fan motor starts
when the call for heat is initiated.
Heating Check - Heat Pump – Check out the heating mode as follows:
1. Start with the unit operating in the cooling mode, then set the room thermostat to HEAT, the fan
switch to ON or AUTO, and the thermostat setpoint above room temperature. Check that the
indoor fan begins to blow warm air.
2. While the unit is running in the heating mode, “force” the unit into a defrost following the instructions in the manufacturer’s service literature. To prevent compressor damage, do not operate
a heat pump in the heating mode for extended periods if the outdoor temperature is
above 65° F.
3. If equipped with supplementary electric heaters, switch the room thermostat to supplemental
heat and verify that the heaters are working.
Heating Check - YAC – Check out the heating mode as follows:
1. If not done previously, turn the gas on and purge the line of air by loosening the ground joint
union slightly until an odor of gas is noticed, then re-tighten it. NEVER PURGE GAS LINES IN
A COMBUSTION CHAMBER. Check all joints for leaks using a leak detecting solution.
2. Check the unit’s burner orifice size, gas input, and manifold pressure before unit start-up.
3. Set the room thermostat to HEAT, the fan switch to ON or AUTO, and the thermostat setpoint
above room temperature.
PACKAGED UNIT INSTALLATION
Table of Contents
Map
Section Topics
10
References
Low outdoor temperatures can affect the heat content of the gas fed to the burners. A calculator
(Figure 10-18) is available that helps determine the orifice size needed for correct burner operation. Orifice size is based on a number of factors including outdoor design temperature, the
heat content and specific gravity of the gas supplied, and the length of exposed gas supply line
pipe. Complete instructions are included on the calculator.
4. Adjust the room thermostat heat anticipator or cycle rate setting to prevent short cycling of the
heating unit. Short cycling prevents the furnace from coming up to operating temperature,
causing condensation to occur in the heat exchanger. Short cycling also contributes to poor
indoor comfort. The procedure for anticipator adjustment is given in the installation instructions
and in Section 8 of this book.
▼ Figure 10-18.
Orifice Size Calculator for Natural Gas
QUICK NOTE
For detailed information and the procedures for measuring airflow, refer to Service Procedures SP-14
through SP-17 in the companion HVAC Servicing Procedures handbook. Refer to Section 8 and/or
Service Procedure SP-13 for the procedure used to measure temperature rise.
Airflow Check – For proper operation of the cooling system, the indoor blower should be moving
400 to 450 CFM of air across the coil for each ton of air conditioning. For heating operation, the
airflow must produce a temperature rise that falls within the range stamped on the unit rating
plate. Tables in the installation instructions give the required temperature rise at various airflow
rates and heating and cooling airflows at various external static pressures. If required, adjust the
indoor blower speed per the manufacturer’s instructions to obtain the proper airflow for the unit.
Final Checks, Adjustments, and Tasks
With the unit operational, perform the following checks to complete the installation:
• Check for correct operation of accessories. If an outdoor air damper or economizer has been
installed, adjust it in accordance with the installation instructions supplied with the damper or
economizer. Check the economizer damper to be sure that the damper position is correct for
the different modes of unit operation.
• Check the unit for any unusual noises or vibration.
• Adjust the balancing dampers in each branch duct for correct operation.
• Clean up the work area.
Before leaving the job site, explain the operation of the complete system to the customer.
Describe how the system operates and run the system through a complete cycle so the customer
can see and hear the normally operating system. If installed, demonstrate the operation of accessories. After the demonstration, present the customer with the owner’s operating and service
manual(s) and warranty.
▼ APPENDIX
DUCTWORK CAPACITY TABLES
BALLPARK FIGURES
RETURN OPENING SIZES
FRICTION LOSSES
ITEM
WET EVAPORATOR
ELECTRONIC AIR CLEANER
SUPPLY DIFFUSER
RETURN GRILLE
FRICTION LOSS
(IN. W.C.)
.25
.10
.05
.05
VELOCITY
TOTAL AREA
(FPM)
CFM/SQ. IN.
TOTAL AREA
Regular or
Relief Grille
500
3.5
FilterGrille
300
2
Undercut
Doors
600
4
ITEM
GAS FURNACE
INSTALLATION &
START-UP CHECKLIST
LOAD CALCULATION AND
EQUIPMENT SELECTION
CONDENSING FURNACES ONLY
■
Combustion air/vent pipe sized per installation
instructions
Combustion air pipe ________ diameter
Vent pipe ________ diameter
■
Termination kit correctly installed
■
Condensate piping installed per installation instructions
■
Heat loss ____________ Btuh @ ____________ °F
design temperature
■
Furnace selected Model # _______________
■
Ductwork sized to handle air delivery of furnace
■
Furnace input rate _______________ Btuh
■
Branch runs at least 6" in diameter with balancing
damper installed
■
Supplied gas heat content _______________ Btu/ft.
■
■
Supplied gas specific gravity _______________
Ductwork insulated and equipped with vapor barrier
(if applicable)
■
Burner orifice size _______________
■
Flexible connectors provided in return and supply ducts
at furnace
AIR DISTRIBUTION SYSTEM
3
FURNACE INSTALLATION
FURNACE START-UP
■
Furnace level and plumb
■
Supply/return ducts securely attached
■
Gas supply pipe sized per installation instructions
Diameter _______________ NPT
■
Gas shut-off, sediment trap, and union installed in gas
pipe
■
Power and thermostat wire sized and installed per
wiring diagram and code
■
Branch circuit wire size _______________ AWG
■
Circuit breaker size _______________ amps
CHIMNEY/VENT INSTALLATION
■
■
■
■
■
■
Gas piping checked for leaks
■
Pilot lit (if applicable)
■
Clean air filter in place
■
All return and supply grilles open and unrestricted
■
Burners fired and input rate checked/adjusted (use
Manifold Pressure Calculator, Cat. #020-444)
■
Temperature rise checked/adjusted and in correct range
Measured rise _______________°F
■
Thermostat heat anticipator setting checked/adjusted
Anticipator setting _______________ amps
■
Limit switch operation checked per installation
instructions
Existing chimney/vent type noted
■ Lined masonry
■ Type-B double-wall
■ Unlined masonry (must reline to use)
Existing chimney/vent adequately sized per installation
instructions
Chimney _____ x _____ B vent _____ diameter
New chimney/chimney liner/vent installed and sized per
installation instructions
Chimney _____ x _____ B vent/liner _____ diameter
Vent connector size and type per installation
instructions
■ Single-wall pipe
■ Double-wall pipe
Vent connector length _______________ ft.
Water heater common-vented with furnace
Water heater input _______________ Btuh
Vent connector _______________ diameter
GENERAL
■
All thermostat functions operate correctly (heat, cool,
fan)
■
Optional and field-installed accessories, such as
humidifiers, operate properly
■
Furnace and ducts checked for noise/vibration
■
Balancing dampers adjusted for correct airflow to each
branch run
■
All work areas cleaned up
■
System operation reviewed with customer and Owner's
Manual presented
RESIDENTIAL SPLIT
SYSTEM COOLING
INSTALLATION &
START-UP CHECKLIST
LOAD CALCULATION AND
EQUIPMENT SELECTION
AIR DISTRIBUTION SYSTEM
■
Ductwork sized to handle 400-500 CFM/ton of capacity
■
Branch runs at least 6" in diameter with balancing
damper installed
■
Ductwork insulated and equipped with vapor barrier
(if applicable)
■
Flexible connectors provided in return and supply duct
at furnace or air handler
■
Air supply and return air grilles open and unrestricted
■
Heat gain ________ Btuh @ ________ °F design temp.
■
Condensing unit selected Model # _______________
■
Evaporator coil selected Model # _______________
■
■
Refrigerant lines sized per installation instructions
Liquid ________ Suction ________ Length ________
Refrigerant lines and indoor coil evacuated to at least
500 microns
■
Service valves opened
■
HACR circuit breaker size ____________amps
■
■
Branch circuit wire size ____________ AWG
All field-made refrigerant line connections checked for
leaks
■
Crankcase heater (if used) energized 24 hours prior to
start-up
■
Compressor and outdoor fan run on call for cooling
■
Refrigerant charge correct (use superheat method for
fixed restrictor metering devices or subcooling method
for TXV-equipped cooling coils)
OUTDOOR UNIT INSTALLATION
■
Unit secured to pad with correct clearance for airflow
and service
■
Raintight disconnect installed within sight of unit
■
Wiring done in accordance with wiring diagram and all
applicable codes
■
Refrigerant lines properly trapped, insulated, secured,
and connected to service valves
■
Shipping brackets/compressor bolts removed and/or
loosened per instructions
■
Optional and field-supplied accessories, such as filter
drier, properly installed
INDOOR UNIT INSTALLATION
OUTDOOR UNIT START-UP
________ °F measured superheat
________ °F measured subcooling
INDOOR UNIT START-UP
■
Condensate flows freely from drain
■
No air leaks in system ductwork
■
Air flows freely from all supply registers
■
Airflow adequate (use airflow range calculator,
Cat. #020-517)
■
"A" coil installed in furnace plenum for proper airflow
and condensate drainage
■
Fan coil securely mounted with provisions for vibration
isolation
■
Secondary drain pan installed under above-ceiling
fan coils
All thermostat functions operate correctly (heat,
cool, fan)
■
All accessory items operate correctly
■
GENERAL
■
Correctly-sized metering device installed (TXV or
metering piston)
■
Outdoor unit/air handler/refrigerant lines checked
for vibration
■
Refrigerant lines properly connected
■
■
Condensate drain installed with trap
Balancing dampers adjusted for correct airflow to each
branch run
■
All accessories/options correctly installed
■
All work areas cleaned up
■
Air filters clean and in place
■
System operation reviewed with customer and Owner's
Manual presented
PACKAGED UNIT
INSTALLATION &
START-UP CHECKLIST
OUTDOOR AIR DAMPER
■
Outdoor air damper properly installed
■
Outdoor air damper set per job specifications
UNIT START-UP
Unless otherwise specified, checklist items apply to all units.
SYSTEM DESIGN
■
Crankcase heater energized 24 hours prior to start-up
■
Compressor and outdoor/indoor fans run on call for cooling
■
Heating and cooling loads properly calculated
■
Airflow adequate
■
Equipment (and electric heat, if applicable) sized in
accordance with local utility and manufacturer directives
■
Refrigerant charge correct
■
Maximum thermal balance point in accordance with local
utility standard
■
Condensate flows freely from drain
■
Compressor and outdoor/indoor fans shut off on a satisfied
call for cooling
■
Compressor and outdoor/indoor fans run on a call for
heating (Heat Pump)
■
Verify defrost cycle operates properly (Heat Pump)
■
Compressor and outdoor/indoor fans shut off on a satisfied
call for heating (Heat Pump)
■
Verify electric heater is working properly (PAC and Heat
Pump)
■
Outdoor thermostats set at proper balance points
■
Circuit breakers, disconnects, and wiring properly sized
■
Properly designed and installed ductwork to handle 400500 CFM/ton capacity
■
Ductwork insulated and equipped with vapor barrier (if
applicable)
UNIT INSTALLATION
■
Unit elevated for snow clearance and defrost water
drainage (if applicable)
■
Burner(s) fired and indoor fan runs on a call for heating
(YAC)
■
Unit placed on pad or curb with correct clearance for
airflow and service
■
Gas input and manifold pressure checked and adjusted (if
required) per installation instructions (YAC)
■
Curb installed per instructions
■
Indoor fan and burner(s) go out on a satisfied call for
heating (YAC)
■
Raintight disconnect(s) installed within sight of unit
■
Indoor fan rpm correct
■
Wiring done in accordance with wiring diagram and code
■
Electrical connections and terminals tight
■
Gas piping done in accordance with installation
instructions, local and national codes (YAC)
■
Gas supply line purged and checked for leaks (YAC)
■
Burner orifices properly aligned (YAC)
■
Vent hood installed per instructions (YAC)
■
Optional and field-supplied accessories installed properly
■
Fan(s) rotate freely without binding or hitting and properly
located in housing/orifice
■
Condensate drain installed per installation instructions
■
Air filters clean and in place
GENERAL
■
Voltage and amperage imbalance for three-phase units are
within accepted limits (2% voltage, 10% amperage)
■
All thermostat functions operate correctly (fan, cool, and
heat)
■
All accessory items operating correctly
■
All supply and return air grilles open and unrestricted
■
Air flows freely from all supply registers. No air leaks in
system ductwork
■
Balancing dampers adjusted for correct airflow to each
branch run
■
All work areas cleaned up. All packing materials removed
from equipment
■
System operation reviewed with customer and Owner’s
Manual presented
DUCT FITTINGS AND EQUIVALENT LENGTHS
LENGTH CONVERSIONS
Fractional
inch
Millimeters
1/32
1/16
3/32
1/8
5/32
3/16
7/32
1/4
9/32
5/16
11/32
3/8
13/32
7/16
15/32
1/2
17/32
9/16
19/32
5/8
21/32
11/16
23/32
3/4
25/32
13/16
27/32
7/8
29/32
15/16
31/32
1
.7938
1.588
2.381
3.175
3.969
4.763
5.556
6.350
7.144
7.938
8.731
9.525
10.32
11.11
11.91
12.70
13.49
14.29
15.08
15.88
16.67
17.46
18.26
19.05
19.84
20.64
21.43
22.23
23.02
23.81
24.61
25.40
Decimal
inch
Millimeters
Inch
Centimeters
Feet
Meters
0.001
0.002
0.003
0.004
.0254
.0508
.0762
.1016
.3048
.4572
.6096
.7620
.1270
.1524
.1778
.2032
3
31/2
4
41/2
.9144
1.067
1.219
1.372
0.009
0.010
0.020
0.030
.2286
0.254
0.508
0.762
5
51/2
6
61/2
1.524
1.676
1.829
1.981
0.040
0.050
0.060
0.070
1.016
1.270
1.524
1.778
7
71/2
8
81/2
2.133
2.286
2.438
2.591
0.080
0.090
0.100
0.200
2.032
2.286
2.540
5.080
9
91/2
10
101/2
2.743
2.896
3.048
3.200
0.300
0.400
0.500
0.600
7.620
10.16
12.70
15.24
11
111/2
12
15
3.353
3.505
3.658
4.572
0.700
0.800
0.900
1.000
17.78
20.32
22.86
25.40
2.54
3.175
3.81
4.445
5.08
5.715
6.35
6.985
7.62
8.225
8.89
9.525
10.16
10.80
11.43
12.07
12.70
13.34
13.97
14.61
15.24
16.51
17.78
19.05
20.32
21.59
22.86
24.13
25.40
26.67
27.94
29.21
1
11/2
2
21/2
0.005
0.006
0.007
0.008
1
11/4
11/2
13/4
2
21/4
21/2
23/4
3
31/4
31/2
33/4
4
41/4
41/2
43/4
5
51/4
51/2
53/4
6
61/2
7
71/2
8
81/2
9
91/2
10
101/2
11
111/2
20
25
50
100
6.096
7.620
15.24
30.48
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
GLOSSARY OF TERMS
ABS (Acrylonitrile Butadiene Styrene)
Plastic material used in the manufacture of pipe and fittings.
Absolute Pressure
Pressure measurements which are compared to absolutely no pressure at all, not
even atmospheric pressure; e.g., psia and in. Hg abs.
ACR Tubing
Air conditioning and refrigeration tubing that is cleaned, dried, and sealed to keep
contaminants from entering the tubing. It is often charged with dry nitrogen.
Adapter
Fitting that joins pipes of different materials or different sizes.
AFUE
Annual fuel utilization efficiency; the annualized average efficiency of a fuel-fired appliance, taking into account the effect of on-off operation.
AGA
American Gas Association.
Air Handler
The device that moves the air across the heat exchanger in a forced-air system. In a
split system, it normally contains the blower fan, cooling coil, metering device, air filter,
and related housing.
Alloy
Any substance made up of two or more metals.
Alternating Current (AC)
An electrical current that reverses (alternates) its direction of flow at regular intervals.
AC is the primary source of energy for homes and businesses and is used when large
amounts of energy are required. (See DC.)
Ambient Temperature
The temperature of the fluid (usually air) surrounding an object.
Ammeter
A device, calibrated in amperes, that is used to measure electric current.
Ampere or Amp (A)
A unit of electric current.
Anchor
A device used to fasten structural members in place.
Anemometer
An instrument used to measure the velocity of airflow.
Annealing
Heat treating to soften metal. Soft copper tubing is made by annealing hard copper.
Aquastat
A temperature-controlled sensory device. It can function both as an operating control
and as a limit control. As an operating control, it can be used as the sensor to control
the level of the water in a device reservoir based on the temperature of the water in the
reservoir. As a limit control, it can be used to turn a device on or off based on the
temperature of the water.
Armored Cable
A flexible, metallic-sheathed cable used for indoor wiring; commonly called BX or
Greenfield.
Arrestor (Lightning Rod)
A device used to protect buildings, including electrical devices, from damage by
lightning.
ASHRAE
American Society of Heating, Refrigerating, and Air-Conditioning Engineers.
Aspect Ratio
In air distribution outlets, this represents the ratio of the length of the core opening of a
grille face or register to the width. In rectangular ducts, it is the ratio of the width to the
depth.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Atmospheric Pressure
The pressure exerted on all things on the Earth’s surface that are a result of the weight
of our atmosphere.
Automatic Changeover Thermostat
A thermostat that automatically selects either heating or cooling, depending on room
temperature and the heating and cooling setpoints.
Axial Load
An external load that acts lengthwise along a shaft.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Back-Seated
The condition of a service valve in which the valve stem is turned fully counterclockwise and the valve is fully open.
Baffle
A sheet metal device that blocks or changes the direction of air, generally to make it
turn a corner or distribute into a room.
Bonding
The permanent adhesion of metallic parts, forming an electrically-conductive path.
Boot
A fitting installed in the airstream at the termination of a branch duct to a room.
Box
A device used to contain wire terminations where they connect to other wires, switches,
or receptacles.
Branch
The portion of the duct system connecting to a main duct.
Branch Circuit
Wiring between the last overcurrent device and the branch circuit outlets or load
device.
Brazing
A method of joining metals using a nonferrous (no iron) filler at a temperature above
800° F.
Break-Away Torque
The torque required to loosen a fastener. This is usually less than the torque required
to tighten the fastener.
Btu (British Thermal Unit)
The amount of heat required to raise the temperature of one pound of water 1° F.
Btuh (Btu’s per hour)
The basic unit for measuring the rate of heat transfer.
Building Code
A set of rules governing the quality of construction in a community. The purpose of
these rules is to protect the public health and safety.
Burr
A sharp, roughened, turned-in edge on a piece of pipe that has been cut but not reamed.
Bus Bar
A rigid conductor at the main power source to which three or more circuits are
connected.
Bushing
(1) A pipe fitting with both male and female threads. Used in a fitting to reduce the size
to connect pipes of different sizes. (2) A device used to mechanically protect and insulate electrical wires passing through abrasive openings.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Cable
A conductor consisting of two or more wires that are grouped together with an overall
covering, such as a plastic sheath.
Capillary Action
Movement of a liquid (in soldering or brazing, nonferrous filler metal) along the surface
of a solid in a kind of spreading action.
Capillary Tube
A long copper tube with a diameter of 1/16 to 1/8 inch.
Used as a refrigerant metering device in small systems where there are relatively
constant loads.
Carbide-Tipped
Refers to cutting tools that have small, extremely hard pieces of carbide steel welded
to the tips.
Caulking
Putty-like mastic used to seal cracks and crevices.
Center Punch
A tool used to make an indentation at the centerline of a hole to be cut.
CFM (Cubic Feet per Minute)
The unit of measure of the volume rate of airflow, as in a heating system.
Chase
A channel formed in buildings to run electrical, plumbing, or mechanical lines; spaces
inside finished walls and between floors used for running ductwork or vent pipes.
Cheek
The flat side of an elbow or offset.
Circuit
An electron path that completes a loop. Circuits generally consist of a power source,
conductors, a load, and a switch to control current flow.
Circuit Breaker
A protective device that opens an electrical circuit when an overload occurs. There are
thermal and magnetic types.
Clamp-On Ammeter
A meter with jaws that are placed around a conductor to measure the current flow
through the conductor.
Coefficient of Performance (COP)
The ratio of work performed in relation to energy used. A rating method for heat pumps.
Collar
A short section of duct that connects to another duct or piece of equipment.
Combustion
The rapid oxidation of fuel gas accompanied by the production of heat, or heat and
light.
Combustion Efficiency
Producing the most heat with the fewest impurities.
Combustion Products
The gases that result from combustion; also called flue gases.
Common Ground Connection
Where two or more grounded wires terminate.
Complete Combustion
Burning in which there is enough oxygen to prevent the formation of carbon monoxide.
Compound Gauge
A service gauge that has both pressure and vacuum scales.
Compression Joint
A method of connection in which tightening a threaded nut compresses a compression
ring to seal the joint.
Compressor
A pump in a refrigeration system that takes refrigerant vapor at a low temperature and
pressure and raises it to a higher temperature and pressure.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Condensate
The liquid formed by condensation of a vapor. In air conditioning, water extracted from
air, as by condensation on the cooling coil of a refrigeration unit.
Condensation
The process by which a gas is changed into a liquid at constant temperature by heat
removal.
Condenser
A heat exchange coil within a mechanical refrigeration system used to reject heat from
the system. The coil where condensation takes place.
Condensing Furnace
A high-efficiency, gas forced-air furnace that uses a second condensing heat exchanger
to extract the latent heat in the flue gas.
Condensing Unit
The portion of a split air conditioning or refrigeration system that is mounted outside
and contains the compressor, condenser, condenser fan motor, and controls for these
components; most used today are air-cooled.
Conductor
A substance or body that allows electricity or heat to pass through it.
Conduit
Rigid or flexible metal or plastic tubing used to enclose electrical wiring.
Connector, Solderless
A device (typically insulated plastic) that uses mechanical pressure rather than solder
to establish a connection between two or more conductors.
Contactor
A device consisting of a coil and one or more sets of contacts used to connect or
disconnect a high-voltage circuit.
Continuity
A continuous current path. Absence of continuity indicates an open circuit.
Control Circuit
That portion of the total circuitry containing devices that apply power to or remove
power from a load.
Cooling Capacity
The rate at which a device can remove heat from a substance, expressed in Btuh. For
an air conditioner, it is the maximum rate at which it removes heat from a space.
Counterbore
Boring a larger hole partway through the stock so that the head of a fastener can be
recessed.
Countersink
Making a flared depression around the top of a hole to receive the head of a flathead
screw; also, the tool used to make the depression.
Coupling
A conduit or pipe fitting containing female threads on both ends. Couplings are used to
join two or more lengths of conduit or pipe in a straight run to join to a fixture.
CPVC (Chlorinated Polyvinyl Chloride)
A type of plastic used to make pipe that will carry hot water and chemicals.
Crawl Space
The space between the floor framing and the ground in a building without a basement.
Crosscut
A cut made across the grain of lumber.
CU. FT. (cu. ft.)
Abbreviation for cubic foot or feet.
CU. IN. (cu. in.)
Abbreviation for cubic inch or inches.
Current
The rate of electron flow in a circuit. Current is measured in amperes.
Cycle
A complete positive and negative alteration of a current or voltage.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Damper
A bladed device used to vary the volume of air passing through an air outlet, air inlet,
or duct.
Deadband
A temperature band, usually 3° F, that separates heating and cooling in an automatic
changeover thermostat.
Defrost
In a heat pump, the process of cycling hot refrigerant through the outdoor coil to melt
accumulated frost.
Dehumidification
The condensation of water vapor from air by cooling the air below the dewpoint or the
removal of water vapor from air by chemical or physical methods.
Dehumidifier
A device used to remove moisture from the air.
Desiccant
Any absorbent or adsorbent, liquid or solid, that will remove water or water vapor from
a material. In a refrigeration circuit, desiccant is contained in a filter-drier.
Device
A unit or component that carries but does not use current, such as a junction box or
switch.
Dewpoint
The temperature of air at which the water vapor content is saturated.
Diffuser
An outlet that discharges supply air into a room in various directions and planes and is
arranged to promote mixing of primary air with secondary room air.
Dilution Air
Air that enters the draft hood of a natural-draft, gas-fired furnace and mixes with the
combustion products.
Direct Current (DC)
An electrical current in which the electron flow is in one direction. DC is used for low
energy applications and allows for precise control.
Direct Vent System
A vent system for a fuel gas-fired appliance which is constructed so that all the air for
combustion is drawn directly from the outside atmosphere and all the flue gases are
discharged to the outside atmosphere.
Disconnect
A manual switching device used to remove power from a circuit. Usually mounted on
or near air conditioning equipment.
Distribution Center
An electric panel used to distribute the electric supply to several branch circuits; can
be of fusible or circuit breaker design.
Draft
The pressure difference that causes the flow of flue gases through a chimney or vent.
See also Natural Draft and Induced Draft.
Draft Gauge
An instrument used to measure air movement by measuring very small air pressure
differences.
Draft Hood
A device built into a natural-draft, gas-fired appliance to decouple the heat exchanger
from the natural-draft vent so that updrafts, downdrafts, or blockages do not adversely
affect the heat exchanger or combustion operation.
Drawband
Flat bar or metal strips with bolted ends; used to make airtight connections on round
ductwork.
Drier
A manufactured device containing a desiccant placed in the refrigerant circuit. Its primary purpose is to collect and hold within the desiccant all water in the system in
excess of the amount which can be tolerated in the circulating refrigerant.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Drop
The vertical distance that the lower edge of a horizontally projected airstream drops
between the outlet and the end of its throw.
Dry Bulb Temperature
Temperature measured using a standard thermometer. A measure of the sensible heat
of the air or surface being measured.
Dual-Fuel Heating System
A system in which a heat pump is combined with a furnace.
Duct
A passageway made of sheet metal or other suitable material; used for conveying air
or other gas at lower pressures.
Dump Zone
An uncontrolled area in a zoned system that is used to avoid low airflow problems that
can result when two or more of the individual system zone dampers are closed, blocking off airflow to the zones.
Dynamic Seal
A seal made where there is movement between two mating parts, or between one of
the parts and the seal.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Economizer
An HVAC device that substitutes outdoor air for the cooled air produced by the air
conditioning system when outdoor air conditions permit. It also controls the amount of
outdoor air used to ventilate a building.
Effective Area
The net area of an outlet or inlet device through which air can pass, equal to the free
area times the coefficient of discharge.
Elbow
A pipe, conduit, or duct fitting that is used to change the direction of fluid flow.
Electrical Metal Tubing (EMT)
Another name for thinwall conduit.
Electric Heater
A device constructed of high resistance wire or other material which produces heat
when a current is passed through it.
Electrolysis
The decomposition of one of two unlike metals in contact with each other in the presence of water.
Energize
To apply voltage to an electric device.
Energy Efficiency Ratio (EER)
The ratio of the rated cooling capacity in Btu’s per hour divided by the amount of
electrical power used in watts at any given set of conditions.
Enthalpy
The total heat content (sensible and latent) expressed in Btu’s per pound of the substance (Btu/lb.).
Equal Friction Method
A method of duct sizing wherein the selected duct friction loss value is used throughout the design of a low-pressure duct system.
Equivalent Length of Pipe
The resistance of a fitting, as compared to the resistance of straight pipe having the
same cross-section.
Evacuation
The process of removing air, moisture, and other gases from the inside of a refrigeration system.
Evaporator
A heat exchange coil within a mechanical refrigeration system used to absorb heat
into the system; the coil where evaporation takes place.
Excess Air
In gas combustion, the amount of air in excess of that needed for complete (stoichiometric) combustion.
External Static Pressure
The total pressure loss of the system ductwork and components external to the supply
fan assembly.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Factory-Installed Wiring
The wiring installed in a piece of equipment at the factory; usually the connections
between the components in the control panel and the system components in the unit
itself.
Fahrenheit Scale (represented as °F)
The scale of temperature measurement most commonly used in the United States.
Fan Brake Power
The actual power required to drive a fan when delivering the required volume of air
through a duct system. It is greater than the power needed to deliver the air because it
includes losses due to turbulence and other inefficiencies of the fan, plus bearing
losses.
Fault Isolation Diagram
A troubleshooting aid usually contained in the manufacturer’s Installation, Start-Up,
and Service Instructions for a particular product.
Feeder
The circuit conductors between the service equipment and the branch circuit overcurrent
device.
Female Thread
Any internal thread.
Field Wiring
The wiring that must be installed in the field by the installation technician.
Filter
A device used to remove dust and contaminant particles from the air.
Filter-Drier
A device in refrigeration systems that removes foreign particles and moisture from
refrigerant.
Fire Damper
A damper in a duct system normally held open by a fusible link which melts at a preset
temperature, allowing the damper blades to close by gravity.
Firestop
Material used to fill air passages in a frame to prevent the spread of fire.
Fish Tape
Flat, steel spring wire with hooked ends; used to pull wires through conduits or walls.
Fittings
The parts of a duct, conduit, or piping system which serve to join lengths of duct,
conduit, or pipe.
Fixed-Orifice Metering Device
A device in which the metering orifice is fixed; may be a piston or capillary tube.
Flame
The zone in which the combustion reaction between a fuel gas and oxygen takes
place with the intense release of light and heat.
Flame Impingement
A condition which exists when the flame of a combustion reaction comes into contact
with the cooler interior surface of the combustion chamber. It causes the reaction to
stop in the impingement area.
Flame Rectification
The phenomenon by which an electrical current flows through a flame; used to prove
the presence of a flame.
Flare Fitting
A fitting in which one end of each tube to be joined is flared outward using a special
tool. The flared tube end mates with the threaded flare fitting and is secured to the
fitting with flare nuts.
Flare Nut
Connects flared copper pipe to a threaded flare fitting.
Flashing
Rust-resistant materials such as copper or aluminum that are installed at joints between roofs and walls or roofs and chimneys to prevent water from entering.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Flexible Connection
A connection using canvas, neoprene, or another soft material; used to dampen vibration and noise.
Flue Gas
Products of combustion plus excess air plus dilution air (on natural-draft appliances)
that pass through the vent.
Flue
The passage that carries combustion gases from a heating system.
Flux
A substance applied to surfaces that are to be joined by soldering or brazing. It prevents oxidation during the heating process.
Follower
The sleeve on a pipe die that aligns the die with the pipe.
Forced-Air Furnace
Any furnace that uses a fan to circulate heated air.
FPM
Abbreviation for feet per minute.
Free Cooling
A mode of economizer operation. It is the cooling provided by outside air rather than
the compressor.
Frequency
The number of complete cycles of an alternating current, sound wave, or vibrating
object that occur in a certain period of time.
Friction
The resistance found at the duct and piping walls. Resistance creates a static pressure loss in systems.
Fuse
A safety device in which a metal link melts when it receives excessive current, thereby
opening the circuit.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
GA (ga)
Abbreviation for gage or gauge.
Galvanized
Protected from rusting by a coating of zinc.
Gas Valve
A device used to start, stop, or regulate the flow of gas.
Gasket
Any semihard material placed between two surfaces to make a watertight or airtight
seal when the surfaces are drawn together by bolts or other fasteners.
Gauge Manifold
A device containing compound and high-pressure gauges, with a valve arrangement
to control fluid flow. Used to measure pressures and perform other service procedures
in a refrigeration system.
Gauge Port
An opening or connection used to attach a gauge during service procedures.
Gauge Pressure
The pressure measured on a gauge, expressed as psig or in. Hg vac.; pressure measurements which are compared to atmospheric pressure.
GPM
Abbreviation for gallons per minute.
Grille
A louvered covering for any opening through which air passes.
Ground Fault Circuit Interrupter (GFCI)
Overcurrent device that detects minute leaks of current and then quickly deenergizes
the circuit.
Ground Fault
A situation in which electricity flows outside the conductors intended to carry power;
e.g., when a hot wire at a bare point touches a grounded component, such as a conduit or grounding wire.
Grounding Conductor
The wire (green or bare) in a cable that carries no current; used as a safety measure to
establish a ground.
Grounding
An electrical safety practice used to prevent a person from being shocked if a tool
being used has an electrical short.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
HACR Circuit Breaker
A circuit breaker with a built-in trip delay commonly used in air conditioning installations due to the power surge on start-up.
Hanger
Support for pipe, conduit, or duct runs.
Hard Start Kit
A kit consisting of a start capacitor and start relay used to provide high starting torque.
Heat Anticipator
A resistive heating element in a thermostat that shuts off the furnace before the space
temperature reaches the setpoint. It prevents the system from overshooting the desired temperature.
Heat Exchanger
A device which provides a means for transferring heat between two fluid streams while
keeping them physically separated.
Heat Gain
The heat transferred into a structure through its outside surfaces and cracks when the
outside temperature is higher than the inside temperature.
Heat Loss
The heat that is transferred out of a structure through its outside surfaces and cracks
when the outside temperature is lower than the inside temperature.
Heat Pump
A comfort system in which the refrigeration cycle is reversed by a four-way valve to
supply heating as well as cooling.
Heat Recovery Ventilator (HRV)
HVAC equipment that saves energy by using a heat exchanger to transfer heat from
the building exhaust air to the cold ventilation air entering the building.
Heater
An electric load that converts electric energy to heat.
Heating Capacity
The rate at which a device can add heat to a substance; it is expressed in Btuh.
Hermetic Compressor
A type of compressor in which the compressor and its drive motor are enclosed in a
welded shell.
Hertz (Hz)
The unit of measure for the frequency of alternating current. One Hertz equals one
cycle per second.
Hickey
A device used to bend conduit.
High Efficiency Particulate Air (HEPA) Filter
A dry-type filter in a rigid frame having a minimum particle-collection efficiency of 99.97%
for 0.3 micron particles.
High-Side
The components of a refrigeration system that are under condensing pressure.
High-Voltage Circuit
The section of a wiring diagram showing distribution of primary AC power to the load
devices.
Horsepower (HP)
A unit of power. One HP represents 33,000 ft. lb. of work per minute and is equal to
746 watts of electrical power.
Hot Surface Ignitor
A device that heats up when an electrical current flows through it; used to ignite gas in
a gas furnace.
Hot Wires
The conductors of a circuit that are not grounded and are carrying power. Also called a
live wire.
Humidifier
A device used to add moisture to the air.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Humidistat
An electrical control that is operated by a change in humidity.
Humidity
The moisture content of air.
HVAC
Heating, ventilating, and air conditioning.
Hydronics
Practice of heating and/or cooling with water.
Hygrometer
An instrument used to measure the degree of moisture in the air.
Hypothermia
A condition of lower-than-normal body temperature resulting from exposure to cold
weather. It can result in death if left untreated.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Ignitor Pack (IGN)
A control device for gas heat that provides a voltage to operate the flame ignitor and a
flame sensor to signal the gas valve to open or close.
IN. (in.)
Abbreviation for inch.
Inches Mercury Absolute (in. Hg abs.)
The scale used to measure absolute pressures equal to or below atmospheric pressure. Also used for weather reporting and forecasting.
Inches Mercury Vacuum (in. Hg vac.)
The scale used to measure gauge pressures equal to or less than atmospheric
pressure.
Incomplete Combustion
Burning in which there is not enough oxygen to prevent the formation of carbon
monoxide.
Indoor Coil
The designation given to the heat pump coil used to transfer heat to or from the conditioned space.
Indoor Fan Relay
An electric relay that starts and stops an indoor fan.
Induced Draft
The draft developed in the heat exchanger of a gas-fired furnace by a fan located at
the outlet of the heat exchanger. May be used with a natural-draft vent, or with a direct
vent system; also called fan-assisted or mechanical draft.
Induced-Draft Furnace
A furnace in which a motor-driven fan draws air from the surrounding area or from
outdoors to support combustion.
Infiltration
The leakage of outside air into a structure through doors, cracks, windows, and other
openings.
Inside Diameter (I.D.)
The distance between the inner walls of a pipe; used as the standard measure for
tubing used in heating and plumbing applications.
Installation Diagram
A diagram that shows little internal wiring but gives specific information as to terminals,
wire sizes, color coding, and breaker or circuit sizes.
Insulation (Electrical)
Nonconducting materials used to cover wires and in the construction of electrical
devices.
Insulator
A device that inhibits the flow of current; opposite of a conductor.
Isolation Transformer
A transformer with a one-to-one turns ratio. It is used for safety and to prevent electrical interference.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Jig
Any type of fixture designed to hold pieces or guide tools while work is being
performed.
Journal
The part of a shaft, axle, spindle, etc., which is supported by and revolves in a bearing.
Jumper
A length of wire used to connect a portion of an electrical circuit.
Junction Box
A box in which connections between circuit conductors are made. A junction box is not
an outlet, since no load is fed from it directly.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
K Grade Copper Pipe
Copper pipe suitable for installation underground.
Knockout
A die-cut impression in electrical boxes and enclosures designed so that it can readily
be removed to provide an opening for access.
KW (kW)
Abbreviation for kilowatt.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
L Grade Copper Pipe
A type of copper pipe used to convey water above ground.
Label Diagram
A diagram usually placed in a convenient location inside HVAC equipment. It normally
depicts a wiring diagram, a component arrangement diagram, a legend, and notes
pertaining to the equipment.
Ladder Diagram
A simplified method for portraying an electrical diagram.
Lay Out
The act of measuring and marking the location of something.
Legend
An explanation of the component abbreviations on a diagram.
Light Emitting Diode (LED)
A semiconductor component that produces light when a current passes through it.
Limit Switch
A protective device used to open or close electrical circuits when temperature or pressure limits are reached.
Line Drop
The voltage drop due to resistance in an electrical conductor.
Line Duty Device
A protective device that opens the motor winding circuit under conditions of excess
current or temperature.
Line Side
The side of a device electrically closest to the source of current.
Line Voltage
The voltage being supplied to the equipment at the power supply.
Liquid Sightglass
The glass-ported fitting in the liquid line used to indicate adequate refrigerant charge.
When bubbles appear in the glass, there is insufficient refrigerant in the system.
Liquid Solenoid Valve
An electrically-operated automatic shutoff valve in the liquid piping that closes on system shutdown to prevent refrigerant migration.
Load Side
The side of a device electrically farthest from the current source.
Load
A device that converts electrical energy into another form of energy (heat, mechanical
motion, light, etc.). Motors are the most common loads in HVAC systems.
Louver
An opening for ventilation consisting of horizontal slats installed at an angle to allow
the passage of air, but exclude rain, light, and vision.
Low-Side
The components of a refrigeration system that are under evaporating pressure.
Low-Voltage Circuit
The control circuit portion of a wiring diagram, termed “low voltage” because it generally operates from a stepped-down voltage.
LPG (LP Gas)
An acronym for Liquified Petroleum Gas; refers to those fuel gases that remain a liquid
under pressure, including propane and butane.
Lugs
Terminals on the ends of a wire or built into electrical devices for the purpose of making connections.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Magnetic Overload Device
A protective device that disconnects a circuit when excessive current creates a magnetic field sufficient to open the contact. Magnetic overload devices are not affected by
the ambient temperature.
Main
The main circuit that supplies all other circuits; also called the main disconnect.
Male Thread
Threads on the outside of a pipe, fitting, or valve.
Malleable Iron
Cast iron that has been heat treated to reduce its brittleness. Pipe fittings are made
from malleable iron.
Manometer
An instrument used to measure low positive, negative, or differential air and gas pressures.
Mastic
A thick adhesive.
Mechanical Cooling
A mode of economizer operation. It is the cooling provided in the conventional manner
by the compressor.
Metering Device
A component of a refrigeration system that controls the flow of high-pressure liquid
into the evaporator.
Microfarad (MFD)
One-millionth of a Farad; the standard unit of measurement for a capacitor.
Microprocessor
A micro-computer chip consisting of integrated circuits which accept, store, and process information and control output devices.
Milliamp
A unit of electric current equal to 1/1,000 of an ampere.
Motor
A device used to convert electrical energy into mechanical energy.
Multimeter
A combination meter used to measure voltage, current, and resistance.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
National Electrical Code® (NEC®)
A nationally-recognized standard that establishes the minimum installation requirements for electrical systems in the United States. It is published by the National Fire
Protection Association (NFPA).
Natural Draft
The draft developed in a chimney or vent of a gas-fired appliance by the difference in
density of the hot flue gas and the outside atmosphere caused by their temperature
difference.
Natural-Draft Furnace
A furnace in which the natural flow of air from around the furnace provides the air to
support combustion. It also depends on the pressure created by the heat in the flue
gases to force them out through the vent system.
Natural Gas
A naturally occurring fuel gas composed of about 95% methane gas with other gases,
such as ethane, hydrogen, carbon dioxide, and nitrogen making up the remainder.
Negative Temperature Coefficient (NTC) Thermistor
A sensing element in which the resistance decreases as the temperature increases.
NTC thermistors are used as temperature sensors and as protective devices in motors.
Neutral Wire
The conductor in a cable that is kept at zero voltage. All current that flows through the
hot wire must also flow through the neutral wire.
NFPA
National Fire Protection Association.
Nipples
Short lengths of pipe (usually less than 12 inches) with male threads on both ends;
used to join fittings.
Normally Closed Contacts
Contacts that close when a relay or contactor is deenergized.
Normally Open Contacts - Contacts that open when a relay or contactor is deenergized.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
O-Ring
A rubber seal used around pipe flanges and stems of some valves to prevent water
leakage.
OC (On Center)
The distance from the center of one structural member to the center of the next structural member.
Occupational Health and Safety Administration (OSHA)
A department of the U.S. government concerned with occupational safety.
Ohm
A unit of electrical resistance.
Oil (Refrigeration)
A specially-formulated compressor lubricating oil used in refrigeration systems.
One Hundred Percent Shutoff Valve
An automatic valve that shuts off all gas to the pilot and prevents gas valve operation
if the pilot is extinguished.
Open Circuit
An electric circuit with a physical break in the path (caused by opening a switch, disconnecting a wire, burning out a fuse, etc.) through which no current can flow.
Orifice
A calibrated hole used to measure or control the flow of a fluid; e.g., a gas orifice is a
precision-drilled hole in a spud that is used to control the flow of gas to a burner.
Outdoor Coil
The heat pump coil used to transfer heat to or from the outdoor air.
Outlet Box
A box used to terminate a cable or conduit. Connections are made in the box. A variety
of covers and plates are available to close the box.
Outside Diameter (O.D.)
The distance between the outer walls of a pipe; used as the standard measure for
ACR tubing.
Overcurrent Protection Device
A fuse or circuit breaker that is used to prevent an excessive flow of current.
Overload
Current demand exceeding that for which the circuit or equipment was designed.
Overload Protector
A device operated by current that shuts the system off when limits are exceeded.
Oxidation
The process by which the oxygen in the air combines with metal to produce tarnish
and rust.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Packaged Unit
A self-contained heating and/or air conditioning system.
Packing
A loosely-packed waterproof material installed in the packing box of valves to prevent
leaking around the stem.
Penny
Measure of nail length. Abbreviated as “d.”
Phillips Head
A type of screw head with a cross-slot.
Pilot
A small flame that is utilized to ignite the gas at the main burner(s) of a gas-fired
device.
Pilot Duty Device
A protective device that opens the motor control circuit under conditions of excess
current or temperature.
Pilot Hole
A small hole drilled to receive the threaded portion of a wood screw.
Pipe Joint Compound
Putty-like material used for sealing threaded pipe joints; commonly called pipe dope.
Piping
A generic term used to refer to all the pipes in a building.
Pitch
The degree of slope or grade given a horizontal run of pipe.
Pitot Tube
A tube used with manometers and differential pressure gauges to measure air velocities and static pressures.
Plenum
A sealed chamber at the inlet or outlet of an air handler. The duct attaches to the
plenum.
Plug
A pipe fitting with external threads and head that is used for closing the opening in
another fitting.
Plumb
Exactly vertical; at a right angle to the horizontal.
Plumb Bob
A pointed weight attached to a line for testing plumbness.
Pneumatic
Operated by air pressure.
Polarized Plug
A plug whose prongs are designed to enter a receptacle in only one orientation.
Polarizing
Using color to identify wires throughout a system to ensure that hot wires will be connected only to hot wires and that neutral wires will run back to the ground terminals in
continuous circuits.
Pole
One set of electric contacts either in an automatic device or a manual switch. Electric
devices such as relays, contactors, switches, and breakers can be purchased with
one or many poles.
Polyethylene
Plastic used to make pipe and fittings primarily for gas piping. Also, a plastic sheet
material used in the building trade as a vapor barrier and to protect building materials
from poor weather during construction.
Positive Temperature Coefficient (PTC) Thermistor
A sensing element in which the resistance increases as the temperature increases.
PTC thermistors are used as temperature sensors and as start assist devices for
motors.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Pounds per Square Inch Absolute (psia)
The scale used to measure absolute pressures.
Pounds per Square Inch Gauge (psig)
The scale used to measure gauge pressures.
Power
The amount of energy consumed by a load in an electrical circuit.
Power Supply
The voltage and current source for an electrical circuit. A battery, utility device, and
transformer are power supplies.
Pressure
Force per unit of area.
Pressure Drop
The pressure difference between two points.
Pressurestat
A pressure switch often used as a protective device for compressors. A bellows or
diaphragm in the switch responds to pressure changes, breaking the circuit if the pressure goes beyond a set value.
Primary Air
Combustion air that is mixed with gas in a burner before leaving the port.
Printed Circuit Board
A support for electronic circuits that generally consists of electrical components linked
by chemically etched (pre-printed) copper foil conductors.
Propane
A member of the methane family of hydrocarbons; used as a fuel gas.
Psychrometer
An instrument used to measure the relative humidity of the air.
Psychrometric Chart
A chart that displays the relationships of air temperature, pressure, and humidity.
Pull Box
A box inserted into a conduit run for the purpose of providing a cable pulling point.
Cable may be spliced in these boxes.
Punch List
A list made by the builder or owner of a structure near the end of construction; it
indicates what must be done before the structure is completely finished and ready for
occupancy.
Purging
Releasing compressed gas to the atmosphere through some part or parts, such as a
hose or pipeline, for the purpose of removing contaminants from that part or parts.
PVC (Polyvinyl Chloride)
A type of plastic used to make plumbing pipe and fittings for water distribution, irrigation, and natural gas distribution.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
R-Value
The thermal resistance of a given thickness of insulating material.
Raceway
A protected runway or enclosure for holding conductors or cables; e.g., conduit, conduit bodies, or cable trays.
Radial Load
The side or radial force applied at right angles to a bearing and shaft.
Re-ignition Pilot
A pilot that is equipped with a device to re-light the pilot gas, either when the pilot is
extinguished or, on furnaces with 100% shutoff valves, each time the furnace is
turned on.
Reaming
Removing the burr from the inside of a pipe that has been cut with a pipe cutter.
Reducer
A pipe fitting having one opening smaller than the other. Reducers are used to change
from a relatively large diameter pipe to a smaller one. In duct systems, it is a fitting
larger on one end than on the other end used to change from one size duct to another.
Redundant Gas Valve
A gas control containing two gas valves in series. If one fails, the other is available to
shut off the gas when needed.
Refrigerant
A fluid (liquid or gas) that picks up heat by evaporating at a low temperature and
pressure. It gives up heat by condensing at a higher temperature and pressure.
Refrigerant Reclaim
The reprocessing of refrigerant to new refrigerant specifications. This requires chemical analysis and usually refers to the processes available at a reprocessing or
manufacturing facility.
Refrigerant Recovery
The removal of refrigerant from a system and placement in a cylinder without testing.
Refrigerant Recycling
The cleaning of refrigerant for reuse by removing moisture, acids, and particulate matter.
Usually applies to procedures performed at the job site or local service shop. The
cleaned refrigerant does not meet new refrigerant specifications.
Register
An air grille equipped with a damper or control valve.
Relative Humidity
The ratio of the amount of vapor contained in the air to the greatest amount the air
could hold at that temperature. Normally expressed as a percentage.
Relay
A magnetically operated device consisting of a coil and one or more sets of contacts
used to connect or disconnect a load.
Resistance
The ability of a device or material to obstruct the current flow within a circuit.
Resistive Circuit
Any circuit that contains at least one resistive load.
Resistor
A device or material that impedes the current flow within a circuit.
Return Air
Air leaving the conditioned space and returning to the air conditioning equipment.
Reverse Cycle Heat
The heat produced by a heat pump when refrigerant flow is reversed from the cooling
mode to the heating mode.
Reversing Valve
A valve that changes the direction of refrigerant flow in a heat pump.
Revolutions per Minute (RPM)
The speed at which a device is rotating.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Rigid Copper Tubing
Hard copper pipe used when installing refrigerant or water lines.
Rip
Sawing lumber in the direction of the grain.
Riser Diagram
A schematic depicting the layout, components, and connections of a piping system.
Riser
A vertical supply pipe extending from a horizontal supply pipe to a fixture or device.
Rollout Switch
A heat-sensitive protective device that opens the circuit if flame migrates away from
the burner box.
Romex®
A trademark for one brand of NM cable (nonmetallic-sheathed cable) used for indoor
wiring.
Rooftop Unit
A heating and/or cooling unit that conditions a structure; it is mounted on the roof after
adequate reinforcement has been built into the roof.
Run
One or more lengths of pipe that continue in a straight line.
Run Capacitor
An electrical storage device that helps motors run more efficiently.
Run-Down Resistance
The torque required to overcome the resistance of associated hardware, such as locknuts and washers, when tightening a fastener.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Safety Pilot
A pilot light with a flame sensing element.
Saturation Temperature
The boiling point of a refrigerant. It is dependent upon pressure.
Schedules
Tables on construction drawings that describe and specify the types and sizes of items
required for the construction of a building.
Schematic Diagram
A diagram that lays out the control system circuit by circuit and is composed of symbols representing components and lines representing their interconnecting wiring.
Schrader Valve
A spring-loaded device similar to a tire valve that allows refrigerant to be added to or
removed from the system.
Seasonal Energy Efficiency Ratio (SEER)
The total cooling of an air conditioner or heat pump in Btu’s during its normal annual
usage period for cooling divided by the total electrical energy input in watt-hours during the same period.
Seasonal Performance Factor (SPF)
A heat pump performance rating that has been adjusted for seasonal operation.
Secondary Air
Combustion air that mixes with the burning gas-primary air mixture in the flame zone.
Semi-Hermetic Compressor
A hermetic (airtight) compressor that can be opened or disassembled by removing
bolts and flanges. Also known as a serviceable hermetic.
Sequencer
A relay with a built-in time delay of a few seconds that allows electric heating elements
to be gradually staged on.
Service Conductors
Electrical conductors that extend from the street main or transformer to the service
equipment of the building being supplied with power.
Service Equipment
Electrical equipment located near the entrance of supply conductors that provides
main control and enables cutoff (via fuses or circuit breakers) for the supply of current
to the building.
Service Panel
The main panel through which electricity is brought from an outside source into a
building and distributed to the branch circuits.
Set or Seizure
In the last stages of rotation in reaching the final torque of a nut or bolt, seizing or set
of the fastener may occur. This is usually accompanied by a noticeable popping effect.
Setpoint
A preset temperature at which a temperature-sensitive switch will open or close.
Shank Hole
A hole drilled for the thicker portion of a wood screw.
Shim
A thin, wedge-shaped piece of material used behind pieces for the purpose of straightening them, or for bringing their surfaces flush at a joint.
Short Circuit
Conducting current, accidental or intentional, between any of the conductors of an
electrical system. This connection may be from line to line or line to neutral (ground).
Short-Cycling
A condition in which a compressor or furnace is restarted immediately after it has been
turned off.
SI (International System of Units)
Includes the common metric units of measure, such as meters, grams, Celsius, Kelvin,
and pascals.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Sightglass
A glass tube or window in a liquid line. It shows the refrigerant or oil in the system and
indicates the presence of gas bubbles in the liquid line.
Single-Phase Voltage
The potential difference produced by a single conductor output from a generating source.
Single-phase voltage produces a single waveform.
Sleeve
A metal form providing a clear opening in concrete for duct or pipe.
Sling Psychrometer
A device with wet and dry bulb thermometers that is whirled rapidly in the air to measure sensible wet and dry bulb temperatures.
Slow Blow Fuse
A fuse with a built-in trip delay commonly used in HVAC installations due to the power
surge on start-up.
SMACNA
Sheet Metal and Air Conditioning Contractors National Association, Inc.
Solder
A fusible alloy used to join metals.
Soldering
The process of joining two metals by using a third metal, a filler, with a melting temperature of less than 800° F.
Soldering Iron
A tool used to melt solder when joining pieces of metal.
Solenoid
A magnetic device that is used to convert electrical energy into mechanical energy.
Many valves are solenoid-activated.
Specific Gravity
Of a gas, the ratio of the weight of a given volume of the gas to the weight of the same
volume of standard air (i.e., air at standard temperature and pressure); for a liquid or
solid, the ratio of the weight of a given volume of the substance to the weight of the
same volume of water at 4° C.
Specific Heat
The amount of heat required to raise one pound of a substance 1° F; expressed in
Btu/lb./°F.
Specification
A document that describes the quality of the materials and the work required. Specifications list the types of tubing, fixtures, hangers, etc. to be used on a project.
Splice
A connection made by joining two or more wires.
Split System
A refrigeration or air conditioning system in which the condenser and evaporator are in
separate locations, joined by refrigerant piping.
Splitter
A hinged sheet of metal used to divert air into a branch duct.
Spread
The divergence of the airstream in a horizontal or vertical plane after it leaves the
outlet.
Spud
A threaded metal device that screws into the gas manifold. It contains the orifice that
meters gas to the burners.
SQ. (sq.)
Abbreviation for square.
SQ. FT. (sq. ft.)
Abbreviation for square foot or feet.
SQ. IN. (sq. in.)
Abbreviation for square inch or inches.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Staged System
A system that has more than one stage of heating or cooling operation.
Staging Thermostat
A thermostat that is designed to open and close more than one set of contacts to
control several stages of heating or cooling operation.
Standing Pilot
A gas pilot that is on continuously.
Start Capacitor
An electric storage device that helps to overcome motor starting torque.
Static Pressure
The pressure exerted by a fluid at rest; for a flowing fluid, as air in a duct, it is the total
pressure minus the velocity pressure.
Subbase
The portion of a two-part thermostat that contains the wiring terminals and control
switches.
Subcooled Liquid
A liquid at a temperature below the saturation temperature of the substance.
Suction Side
The low-pressure side of a refrigeration system, extending from the metering device
through the evaporator to the inlet valve of the compressor.
Superheated Gas
A gas at a temperature above the saturation temperature of the substance.
Supply Air
Air that has been treated at the conditioning device for distribution to the conditioned
space.
Swaging
Enlarging one end of a tube using a special tool so that another tube of the same size
can fit within it in preparation for making a solder or braze connection.
Sweating
A method of joining pipe in which solder is applied to the joint and heated until it flows
into the joint.
Switch
A device used to connect and disconnect the flow of current or to divert current from
one circuit to another.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
T or T Fitting
A fitting shaped like the letter “T.” Each leg of the T can be joined to a pipe, duct, or
another fitting.
Takeoff
(1) The process of surveying, measuring, itemizing, and counting all materials and
equipment needed for a construction project, as indicated by the drawings. (2) A duct
fitting used to make the transition between a main duct and a branch duct.
Temperature
The measure of the intensity of heat that a substance possesses.
Temperature Rise
The positive change in temperature of air passing through a heat exchanger as a
result of heat transfer.
Tempered
Metal that is treated in a special way to be harder and stronger.
Template
A pattern or guide for cutting or drilling.
Terminal
A point on an electrical device where connections may be made.
Thermal Overload Device
A bimetal protective device that acts as a switch contact, disconnecting the circuit
under conditions of excessive heat.
Thermocouple
A device comprised of two dissimilar metals that generates an electrical potential in
the presence of heat.
Thermometer
A device used to measure temperature.
Thermostat
A device that connects or disconnects a circuit in response to a change in the ambient
temperature.
Thermostat Body
The portion of a two-part thermostat that contains the heating and cooling
thermostats.
Thermostatic Expansion Valve (TEV or TXV)
A valve used to control superheat in a refrigeration system by regulating the flow of
liquid refrigerant to the evaporator.
Three-Phase Voltage
The potential difference produced by three conductors spaced 120° apart in a generating source. Three-phase voltage produces three waveforms, each out of sync with
the others by one third of a cycle.
Throw
The horizontal or vertical axial distance an airstream travels after leaving an air outlet
before the maximum stream velocity is reduced to a specific terminal level as specified
by the outlet device manufacturer; e.g., 200, 150, 100, or 50 FPM.
Thrust
The force acting lengthwise along the axis of a shaft, either toward it or away from it.
Time Delay Relay
A relay in which there is a delay between the time the coil is energized or deenergized
and when the contacts open or close. Often used to control fans for greater heating or
cooling efficiency.
Tolerance
The amount of variation allowed from a standard.
Ton
The basic large unit for measuring the rate of heat transfer (12,000 Btuh).
Torque
The force that must be generated to turn a motor. Also, the resistance to turning or
twisting.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Total Cooling Load (Expressed in Btuh or tons)
The rate at which total heat enters a space.
Total Pressure
The sum of the static pressure and the velocity pressure in an air duct. It is the pressure produced by the fan or blower.
Transformer
A device used to raise and lower AC voltage levels.
Transition
A duct fitting that changes from one geometric shape to another, as square to round.
Troubleshooting Table
A troubleshooting aid usually contained in the manufacturer’s Installation, Start-Up,
and Service Instructions for a particular product. Troubleshooting tables are intended
to guide the technician to a corrective action based on observations of system
operation.
Tubing
Thin-wall pipe that can be easily bent.
Turning Vanes
A series of small radius blades evenly spaced along the diagonal, parallel to the turn of
a duct elbow.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Union
A fitting used to join two lengths of pipe. It permits disconnecting the two pieces of pipe
without cutting.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Vacuum
Any pressure below atmospheric pressure.
Vacuum Pump
A pump used to remove air and moisture from a refrigeration system at a pressure
below atmospheric pressure.
Vapor Barrier
A moisture-impervious layer applied to the surfaces enclosing a humid space to prevent moisture travel to a point where it may condense due to lower temperature.
Velocity
How fast air is moving; usually measured in feet per minute.
Velocity Pressure
The pressure in a duct due to the movement of the air. It is the difference between the
total pressure and the static pressure.
Velometer
An instrument that measures the velocity of air or water.
Vent
A passageway used to convey flue gases from gas-burning equipment to the outside
atmosphere.
Vent Connector
A pipe or duct which connects a gas-burning appliance to a vent or chimney.
Vent Damper
A device intended for installation in the venting system at the outlet or downstream of
a gas-burning appliance to automatically open the vent when the appliance is in operation and to automatically close off the vent when the appliance is off.
Ventilation
The process of supplying or removing air, by natural or mechanical means, to or from
any space. Such air may or may not have been conditioned.
Venturi
The flared-shape portion of a burner nearest the gas orifice that is designed to assist
the gas jet in injecting air into the burner. Also a ring or panel surrounding the blades of
a propeller fan used to improve fan performance.
Volt
A unit of electrical potential.
Voltage
An electrical measurement of the potential for electron flow within a circuit.
Voltage Drop
The amount of voltage required for a single load in a circuit.
Volume
The amount of air in cubic feet flowing past a given point in one minute (measured in
CFM).
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Watt
A unit of electrical power.
Wet Bulb
A device used to measure relative humidity. Evaporation of moisture lowers the temperature of the wet bulb compared to the dry bulb temperature of the same air sample.
Wet Bulb Temperature
A measure of humidity in the air.
Wetting
A process that reduces the surface tension so that molten (liquid) solder flows evenly
throughout a joint.
Wire Gauge
A standard numerical method of specifying the physical size of a conductor. The American Wire Gauge (AWG) series is the most common.
Wire Nut
A solderless connector for joining wires.
Wiring Diagram
Also known as a wiring schematic, a wiring diagram is that portion of a label diagram
which illustrates the internal wiring of the unit.
A B C D E
F G H
I
J
K
L M N O P R S
T
U V W Z
Manual Table of Contents
Zone Damper
A damper used to control airflow to a zone in a zoned comfort system.
Zone Valve
A thermostat-controlled valve used in hydronic heating and cooling systems to control
the temperature in a certain area or zone.
Zoning
The practice of providing independent heating and/or cooling to different areas in a
structure.
INDEX
A
Accessories
Gas Furnace
Condensate pumps 107
Electronic air cleaners 106
Humidifiers 106
Packaged units 149
Economizer 148
Outdoor damper kits 148
Split systems 125
Indoor units 126
Outdoor units 128
Acetylene 21
ACR copper tubing 57
Adjusting
Gas input rate 120
Temperature rise 121
Thermostat heat anticipator 122
Air distribution system
Basic 72
Installing ductwork 117, 152
Air system balancing, forced-air duct
systems
Cooling 85
Heating 85
Air-acetylene torches 60
Airflow check, packaged units 155
Alloys 60
Anchors, self-drilling snap-off 44
Armored cable
Cutting and removing the armor
sheath 92
Fastening to electrical boxes 93
B
Bending soft copper tubing 58
Black iron/galvanized steel pipe and fittings
66
Blind (pop) rivets, installing 48
Blower-off delay relay 128
Bolts, machine 45
Branch supply and return ducts,
installing 77
Brazing
Air-acetylene torches 60
Alloys 60
Fluxes 60
General procedure for 63
Oxyacetylene torches 60
Ignition and adjustment 62
Set-up 61
Purging 65
Safety 27
Building electrical service, typical 87
BX cable (See armored cable)
C
Cable runs. installing
Low-voltage control cable 100
Nonmetallic cable 100
Category I vents (See Induced-draft
furnace vent systems)
Category II vents (See Condensing furnace
vent systems)
Chalk lines 7
Changing fan speed 83
Checking safety controls
Pressure switch 123
Primary limit switch 123
Checklists
Gas furnaces 158
Packaged units 160
Residential split system cooling 159
Circuit breakers and fuses 88
Cold weather precautions 28
Compressor
Short cycle protector 131
Start assist kits 131
Condensate
Drain piping 152
Installing 136
Drains, installing 119
Pumps 107
Condensing furnaces 103
Vent systems, installing 110
Conduit runs, installing 101
Confined spaces 29
Connecting refrigerant lines to indoor and
outdoor units
Brazing the connections 141
Mechanical connections 141
Conversions
Length 166
Weights and measures 164
Cooling checks, packaged units 153
Crankcase heaters 129
Customer relations 11
Cutting
And deburring copper tubing 58
And joining 69
And reaming steel pipe 67
D
Damper
Volume 75
Zone 75
Deburring copper tubing 58
Diffuser capacity tables 156
Disconnect/safety switches 90
Dollies 50
Downflow furnaces 104
Drain piping 136
Installing 136
Drains, Installing 119
Drill sizes 169
Drills
Cordless 7
Electric 7
Duct fittings 161
Ductwork capacity tables 156
E
Economizer 148
Electric heaters 128
Electrical equipment safety
Electric Shock 17
Electrical burns 17
Lock out/tagout 18
Electrical metal tubing (EMT)
Bending 94
Cutting 94
Fastening to electrical boxes and fittings
94
Joining 94
Electrical symbols 168
Electronic air cleaners 106
Epoxy anchoring systems 44
Equipment/material moving devices
Hand trucks, dollies, and pry bars 50
Ratchet pullers 50
Evaporator freeze protection
thermostat 132
Evaporator/indoor coils
Installing cased coils 134
Installing uncased coils 133
Exposure to refrigerants 19
Extension cords 10
Extreme hot and cold weather precautions
Cold weather precautions 28
Hot weather precautions 28
F
Fan capacity table 157
Fan coil units 127
Installing air distribution system ductwork
to 135
Installing and leveling the fan coil 135
Installing the fan coil power and control
wiring 135
Locating the fan coil 135
Fan speed, changing 83
Fastener grade designations 46
Fasteners and anchors, installing
Blind (pop) rivets 48
Epoxy anchoring systems 44
Guidelines for drilling anchor holes in
masonry 44
Hammer-driven pins and studs 42
Keys 48
Machine bolts, screws, and related
hardware
Fastener grade designations 46
Flat and lock washers 46
Machine bolts, screws, and studs 45
Nuts 46
Set screws 46
Thread designations 45
Masonry and hollow-wall anchors 43
Nails 41
Powder-actuated drivers and
fasteners 43
Screws 41
Self-drilling, snap-off anchors and
fasteners 44
Threaded fasteners, installing
Tightening sequence and torquing
guidelines 47
Torque wrenches 47
Toggle bolts 43
Fiberglass ductwork 82
Field wiring, HVAC
Building electrical service, typical 87
Equipment branch circuit components
Circuit breakers and fuses 88
Disconnect/safety switches 90
Wires, cables, and connectors 91
Gas furnaces 105
Packaged units 155
Split systems 145
Thermostat control circuit components
Thermostat wire 96
Thermostats 96
Unit electrical installation guidelines 97
Cable runs 100
Conduit runs 101
Sequence and use of installation
instructions 98
Wires in wall partitions 101
Fittings and transitions 73
Flaring and swaging soft copper tubing 58
Flat and lock washers 46
Flexible conduit 94
Flexible ductwork 81
Fluxes 60
Folding rules 5
Forced-air duct system
Balancing the air system
Thermometer balancing for cooling 85
Thermometer balancing for heating 85
Basic air distribution system 72
Changing fan speed 83
Fiberglass ductwork 82
Flexible ductwork 81
Galvanized steel ductwork systems
Fittings and transitions 73
Installation guidelines 75
Supply outlets and return grilles 74
Trunk and branch ducts 73
Volume dampers 75
System fans 83
Friction losses 156
Furnaces (See Gas furnaces)
G
Galvanized steel ductwork systems
Fittings and transitions 73
Installation guidelines
Branch supply and return ducts 77
Insulation and vapor barriers 80
Main supply and return trunks 76
Noise and vibration control 79
Plenum and supply trunk starting
collar 75
Supply diffusers and return grilles 78
Supply outlets and return grilles 74
Trunk and branch ducts 73
Volume dampers 75
Gas and oil heating equipment
Gas leaks 22
Incomplete combustion 23
Oil leaks 22
Other gas and oil heating precautions 23
Standing leak test and purging 23
Gas furnaces
Accessories
Condensate pumps 107
Electronic air cleaners 106
Humidifiers 106
Configurations
Downflow furnaces 104
Horizontal furnaces 104
Multi-poise furnaces 104
Natural gas and propane gas
furnaces 105
Upflow furnaces 104
Conversion kits 105
Installation guidelines
Air distribution system ductwork 117
Checklist 158
Condensate drains 119
Final checks, adjustments, and
tasks 123
Gas piping 117
Induced-draft furnace combustion and
ventilation 115
Initial preparation 114
Installing 117
Leveling 117
Locating the furnace 114
Power and control wiring 118
Removal of an existing furnace 114
Start-up and checkout 120
Vents 119
Types
Condensing 103
Induced draft 103
Natural draft 103
Gas leaks 22
Gas piping and fittings 66
Assembling 68
Black iron/galvanized 65–67
Cutting and reaming 67
Installing 117
Threading 67
H
Hammer-driven pins and studs 42
Hand tool set 5
Hand trucks 50
Hard ACR copper tubing 57
Hazard communication standard 29
Hazardous waste management 29
Heat pump units 147
Heating check
Heat pump 154
PAC with electric resistance heat 154
YAC 154
Heating symbols 167
High-pressure switches 131
Hoisting (See Rigging)
Horizontal furnaces 104
Hot weather precautions 28
Humidifiers 106
HVAC equipment branch circuit
components
Circuit breakers and fuses 88
Disconnect/safety switches 90
Wires, cables, and connectors
Armored cable (BX cable) 92
Electrical metal tubing 93
Flexible conduit 94
Intermediate metal conduit 93
Nonmetallic sheathed cable 91
Rigid metallic conduit (See also
Intermediate metal conduit; Electrical
metal tubing) 93
Rigid nonmetallic conduit 94–95
Wire connectors/terminals 95
HVAC thermostat control circuit
components
Thermostat wire 96
Thermostats 96
HVAC unit electrical installation guidelines
Cable runs
Low-voltage control cable 100
Nonmetallic cable 100
Conduit runs 101
Sequence and use of installation
instructions 98
Wires in wall partitions 101
Customer relations 11
Installation and start-up checklists 5
Planning the installation 4
Tasks and sequence 4
Tools and equipment
Hand tool set 5
Ladders 10
Tools, measuring and layout 5
Tools, portable 7
Insulation, installing 80
Intermediate metal conduit (IMC)
Bending 94
Cutting 94
Fastening to electrical boxes and
fittings 94
Joining 94
I
L
Incomplete combustion 23
Indoor equipment
Condensate drain piping, installing 136
Evaporator/indoor coils 133
Cased coils, installing 134
Uncased coils, installing 133
Fan coil unit
Air distribution system ductwork,
connecting 135
Installing and leveling 135
Locating 135
Power and control wiring,
connecting 135
Induced-draft furnaces 103
Combustion and ventilation 115
Supplying inside air to a confined
space 116
Supplying outdoor air to a confined
space 116
Vent systems 107
Metal vents, installing 108
Vent connectors, installing 108
Venting through a masonry chiminey,
general guidel 109
Installation and start-up
checklists 5, 158
Installation guidelines
Branch supply and return ducts 77
Insulation and vapor barriers 80
Main supply and return trunks 76
Noise and vibration control 79
Plenum and supply trunk starting
collar 75
Supply diffusers and return grilles 78
Installation, overview
Ladders 10, 25
Leak testing and evacuating the refrigerant
lines 142
Length conversions 166
Levels 7
Lifting 16, 52
Line sets 57
Liquid petroleum 21
Liquid solenoid valve 131
Load size, weight, and center of gravity 53
Location, selecting
Gas furnaces 114
Packaged units
All units 150
Roof-mounted units 150
Slab-mounted units 150
Split systems 137
Lock out/tagout 18
Low-ambient temperature controller 128
Low-pressure switches 131
Low-voltage control cable 100
K
Keys 48
M
Machine blots, screws, and related
hardware
Fastener grade designations 46
Flat and lock washers 46
Machine bolts, screws, and studs 45
Nuts 46
Set screws 46
Thread designations 45
Main supply and return trunks,
installing 76
Masonry and hollow-wall anchors 43
Measuring tapes 5
Mechanical equipment
Hot and cold surfaces and work
areas 18
Rotating and moving parts 18
Sharp objects 18
Metal vents, installing 108
Metering device, installing 139
Mounting the unit 137
Moving (See Rigging)
Multi-poise furnaces 104
N
Nails 41
Natural gas furnaces
Furnace conversion kits 105
Natural gas 105
Natural-draft furnaces 103
Nitrogen 20
Noise control, installing 79
Nonmetallic cable 100
Nonmetallic sheathed cable
Connecting grounding wires 92
Cutting and stripping 91
Fastening to electrical boxes 92
Nuts 46
O
Oil leaks 22
Outdoor damper kits 148
Outdoor equipment, installing
Locating the unit 137
Mounting the unit 137
Power and control wiring 138
Oxyacetylene torches 60
Ignition and adjustment 62
Set-up 61
Oxygen 21
P
Packaged units
Accessories 148
Economizer 148
Outdoor damper kits 148
Heat pump units 147
PAC units 147
Packaged unit installation guidelines 149
Air distribution system ductwork 152
Checklist 160
Condensate drain piping 152
Final checks, adjustments, and
tasks 155
Initial preparation 150
Locating the unit 150
Power and control wiring 153
Preparing slab or rooftop sites 150
Rigging and placing the unit 151
Start-up and checkout 153
Vent hood and gas piping (YAC) 153
PTAC units 147
YAC units 147
Personal safety
Equipment 15
Lifting 16
Loose-fitting clothing and jewelry
hazards 16
Pipe hangers and supports 70
Pipe types and sizes 68
Piping systems
Gas piping and fittings 66
Assembling steel pipe and fittings 68
Black iron/galvanized steel pipe and
fittings 66
Cutting and reaming steel pipe 67
Threading steel pipe 67
Pipe hangers and supports 70
Plastic piping and fittings
Cutting and joining 69
Pipe types and sizes 68
Refrigerant copper pipe/tubing and
fittings
Bending soft copper tubing 58
Cutting and deburring copper
tubing 58
Flaring and swaging soft copper
tubing 58
Handling ACR copper tubing 57
Hard ACR copper tubing 57
Line sets 57
Soft ACR copper tubing 57
Soldering and brazing copper tubing 27,
59–60
Planning the installation 4
Plastic piping and fittings
Cutting and joining 69
Pipe types and sizes 68
Plenum and supply trunk starting collar,
installing 75
Plumb bobs 7
Plumbing symbols 167
Powder-actuated drivers and fasteners 43
Power and control wiring 138, 153
Installing 118
Power tools, safety precautions 24
Pressurized gas hazards
Acetylene 21
Liquid petroleum 21
Nitrogen 20
Oxygen 21
Refrigerants 19
Propane gas furnaces
Furnace conversion kits 105
Propane gas 105
Pry bars 50
PTAC units 147
Purging while soldering/brazing 65
PVC conduit (See Rigid nonmetalic
conduit)
PVC vent and combustion air pipes,
installing 110
R
Ratchet pullers 50
Reaming steel pipe 67
Refrigerant
Containers 19
Exposure to 19
Tubing lines, installing 139
Connection to indoor and outdoor
units 140
Leak testing and evacuating 142
Metering device 139
Vapor line considerations 140
Return air capacity tables 156
Return openings 156
Rigging
Equipment/material moving devices
Hand trucks, dollies, and pry bars 50
Ratchet pullers 50
General rigging procedures
Inspecting rigging equipment 54
Load size, weight, and center of
gravity 53
Rigging and moving loads 55
Rigging and placing the unit 151
Rigging equipment and attachment
hardware
Lifting slings 52
Safety 27
Wire and fiber ropes 51
Rigid metallic conduit (See also
Intermediate metal conduit) 93
Rigid nonmetallic conduit 94
Roof-mounted units 150
S
Safety
Electrical equipment
Electric shock 17
Electrical burns 17
Lock out/tagout 18
Extreme hot and cold weather
precautions
Cold weather precautions 28
Hot weather precautions 28
Gas and oil heating equipment
Gas leaks 22
Incomplete combustion 23
Oil leaks 22
Other gas and oil heating
precautions 23
Standing leak test and purging 23
General safety awareness
Confined spaces 29
Hazard communication standard 29
Hazardous waste management 29
Mechanical equipment
Hot and cold surfaces and work
areas 18
Rotating and moving parts 18
Sharp objects 18
Personal safety
Equipment 15
Lifting 16
Loose-fitting clothing and jewelry 16
Refrigerant and other pressurized gases
Exposure to refrigerants 19
Other pressurized gas hazards 20
Refrigerants containers 19
Summary of dangers, warnings, cautions,
and safety 30
Tool use precautions, installation
Ladders and scaffolding 25
Power tools 24
Rigging equipment 27
Soldering and brazing equipment 27
Saws
Band 10
Circular 8
Jig 8
Reciprocating 8
Scaffolding 25
Screws 41
Machine 45
Self-drilling, snap-off anchors 44
Set screws 46
Sharp objects 18
Slab-mounted units 150
Soft ACR copper tubing 57
Soldering copper tubing 59
Air-acetylene torches 60
Alloys 60
Fluxes 60
General procedure for 63
Oxyacetylene torches 60
Ignition and adjustment 62
Set-up 61
Purging 65
Safety 27
Splicing wires 95
Split systems
Accessories 127
Used with indoor units 128
Used with outdoor units 128
Final checks, adjustments, and
tasks 145
Split system installation guidelines
Checklist 159
Indoor equipment 133
Outdoor equipment 137
Refrigerant tubing lines 139–140
Split systems and components
Fan coil units 127
Indoor evaporator coil units 126
Split cooling systems 125
Split heat pump systems 126
Start-up and checkout 153
Squares 6
Standing leak test and purging 23
Start-up and checkout
Gas furnaces 158
Adjusting gas input rate 120
Adjusting temperature rise 121
Adjusting thermostat heat
anticipator 122
Checking safety controls 122
Packaged units 160
Airflow check 155
Cooling checks 153
Heating checks 154
Steel pipe and fittings
Assembling 68
Black iron/galvanized 66
Studs, machine 45
Supply diffusers and return grilles,
installing 78
Supply outlet and return grilles 74
Supplying air to a confined space 116
Symbols
Electrical 168
Heating 167
Plumbing 167
System fans 83
T
Tasks and sequence 4–5
Thermometer
Balancing for cooling 85
Balancing for heating 85
Thermostat wire 96
Thermostats 96
Thinwall conduit (See Electrical metal
tubing)
Thread designations 45
Threaded fasteners, installing
Tightening sequence and torquing
guidelines 47
Torque wrenches 47
Threading steel pipe 67
Toggle bolts 43
Tools
Hand tools 5
Torque wrenches 47
Ladders 10
Measuring and layout
Chalk lines 7
Folding rules 6
Levels 7
Measuring tapes 6
Plumb bobs 7
Squares 6
Portable
Drills 7
Extension cords 10
Saws 8–9
Use precautions
Ladders and scaffolding 25
Power tools 24
Rigging equipment 27
Torquing guidelines, threaded fasteners 47
Trunk and branch ducts 73
U
Upflow furnaces 104
V
Vapor barriers, installing 80
Vapor line considerations 140
Vent systems, installing
Condensing furnace 110
Induced-draft furnace 107
Vent connectors 108
Vent hood and gas piping (YAC) 153
Vents 119
Vibration control, installing 79
Volume dampers 75
W
Weights and measures conversion chart
164–165
Winter start control and time delay relay
kits 132
Wire and fiber ropes 51
Wire connectors/terminals 95
Connecting wires to terminals 95
Splicing wires 95
Wires, cables, and connectors
Armored cable
Cutting and removing the armor
sheath 92
Fastening to electrical boxes 93
Electrical metal tubing
Bending 94
Cutting 94
Fastening to electrical boxes and
fittings 94
Joining 94
Flexible conduit 94
Intermediate metal conduit
Bending 94
Cutting 94
Fastening to electrical boxes and
fittings 94
Joining 94
Nonmetallic sheathed cable
Connecting ground wires 92
Cutting and stripping 91
Fastening to electrical boxes 92
Rigid metallic conduit (See also
Intermediate metal conduit; Electrical
metal tubing) 93
Wire connectors/terminals 95
Connecting wires to terminals 95
Splicing wires 95
Wires in wall partitions, installing 101
Y
YAC units 147
Z
Zone dampers 75
Zoning 75
Installation Manual Tools and Equipment
Air-Acetylene Torch 60
Appliance Truck 50
Aviation (Sheetmetal) Shears 76
Band Saw (Portable) 10
Blind (Pop) Rivet Tool 48
Cable Stripper (Ripper) 91
Calculator - Natural Gas Furnace Manifold
Pressure 120
Calculator - Orifice Natural Gas 155
Calculator - Required Superheat / Subcooling
144
Carpenter’s / Framing Square 6
Chalk Line 7
Circular Saw / Blades 9
Combination Square 6
Conduit Bender (Hickey) 94
Containers (Refrigerant) 19
Dolly 50
Drawband Tightening Tool (Flexible Duct) 81
Drill Bits 8
Driver Drill and Charger (Cordless) 7
Ductboard Fabrication (Grooving) Tools 82
Electric Drill 8
Electric Shear (Sheetmetal) 76
Electronic Leak Detector (Refrigerant) 142
Extension Cords 10
Extension / Straight Ladders 10, 11
Fish Tape 94
Flaring Tool 58
Folding Rules 6
Friction Lighter 61
Gauge Manifold Set 143, 144, 145
Gauge-Equipped Pressure Regulator 20, 65
Ground Fault Circuit Interrupter 17
Hacksaw 92
Hammer Drill 8
Hammer Driven Tool 42
Hand Tool Set 5
Hand Truck 50
Insulated Fuse Puller 90
Jig / Saber Saw 9
Levels / Spirit Levels 7
Lineman’s Pliers 91
Manometer 121
Measuring Tape 6
Multi-Purpose Tool 91
Oxyacetylene Torch 60
Pipe Cutter 67
Pipe Wrenches 68
Pipe Reamer 67
Pipe Threader (Hand) and Die Heads 67
Plumb Bob 7
Powder-Actuated Driver 43
Pry Bars 50
Rachet Pullers (Come-Along) 50
Reciprocating Saw 9
Saber Saw 9
Scaffold (Metal) 26
Slings (Lifting) 52
Step Ladder 11, 25, 26
Straight Snips (Sheetmetal) 76
Swaging Tool 58
Thermometer 85
Torque Wrench 47
Tube Reamer / Burr Remover 58
Tubing Cutter (Copper) 58
Tubing Shear (Plastic) 69
Tubing Bender (Soft Copper) 58
Tubing Cutter (Plastic) 69
Vacuum Pump 142
Vacuum Gauge 142
Vice (Pipe) 67
Wire Rope 51
Thimbles 51
Shackles 51
Sockets 51
U-Bolts 51
Wire Stripper (Small Gauge Wires) 97
CORE SKILLS
Section 1
SYSTEM INSTALLATION
REQUIREMENTS
The Organized
Installation
Section 2
Safety
Section 3
Installing Fasteners
and Anchors
Section 4
Rigging, Hoisting,
and Moving
Section 5
Piping Systems
Section 6
Forced-Air
Duct Systems
Gas Furnace
Installation
Section 8
Split System
Installation
Section 9
Packaged Unit
Installation
Section 7
Field Wiring
Section 10
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement