A.O. Smith | 300A | Operating instructions | A.O. Smith 300A Operating instructions

CYCLONE Xi® Model BTH 300A, 400A, 500A
COMMERCIAL GAS WATER HEATER
GAS-FIRED POWER BURNER
FOR DOMESTIC HOT WATER
• INSTALLATION • OPERATION • SERVICE • MAINTENANCE • LIMITED WARRANTY
WARNING: If the information in these
instructions is not followed exactly, a fire
or explosion may result causing property
damage, personal injury or death.
– Do not store or use gasoline or other flammable vapors and liquids in the
vicinity of this or any other appliance.
– WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electrical switch;
do not use any phone in your
building.
• Immediately call your gas supplier
from a neighbor's phone. Follow the
gas supplier's instructions.
• If you cannot reach your gas supplier,
call the fire department.
– Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
Thank you for buying this energy efficient water heater from
A.O. Smith Water Products Company. We appreciate your
confidence in our products.
CAUTION
TEXT PRINTED OR OUTLINED IN RED CONTAINS
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE
READ THOROUGHLY BEFORE INSTALLING AND USING
THIS APPLIANCE.
www.hotwater.com
PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.
PRINTED 0307197373-003
ROUGH-IN-DIMENSIONS
GAS VALVE PIPING
BTH-300
BTH-400
BTH-500
1 1/4" NPT
1 1/4" NPT
1 1/2" NPT
TABLE 1 RECOVERY CAPACITIES.
TYPE OF
INPUT
MODEL
GAS
BTUH
KW
300,000
BTH-300 NATURAL
88
300,000
BTH-300 PROPANE
88
399,900
NATURAL
BTH-400
117
399,900
BTH-400 PROPANE
117
BTH-500 NATURAL 499,900
146
499,900
BTH-500 PROPANE
146
Approx.
Capacity
130 US Gals.
492 Litres
130 US Gals.
492 Litres
130 US Gals.
492 Litres
130 US Gals.
492 Litres
130 US Gals.
492 Litres
130 US Gals.
492 Litres
F°
C°
GPH
LPH
GPH
LPH
GPH
LPH
GPH
LPH
GPH
LPH
GPH
LPH
U.S. Gallons/Hr and Litres/Hr at TEMPERATURE RISE INDICATED
20F°
11C°
1746
6610
1746
6610
2328
8813
2328
8813
2878
10894
2878
10894
30F°
17C°
1164
4406
1164
4406
1552
5875
1552
5875
1919
7263
1919
7263
40F°
22C°
873
3304
873
3304
1164
4406
1164
4406
1439
5447
1439
5447
50F°
28C°
699
2644
699
2644
931
3525
931
3525
1151
4358
1151
4358
60F°
33C°
582
2203
582
2203
776
2938
776
2938
959
3631
959
3631
70F°
39C°
499
1888
499
1888
665
2518
665
2518
822
3113
822
3113
80F°
44C°
436
1652
436
1652
582
2203
582
2203
720
2724
720
2724
90F°
50C°
388
1469
388
1469
517
1958
517
1958
640
2421
640
2421
100F°
56C°
349
1322
349
1322
466
1763
466
1763
576
2179
576
2179
110° 120F° 130F°
61C° 67C° 72C°
318
291
269
1201 1102 1017
318
291
269
1201 1102 1017
423
388
359
1602 1469 1356
423
388
359
1602 1469 1356
523
480
443
1981 1816 1676
523
480
443
1981 1816 1676
140F°
78C°
250
945
250
945
332
1259
332
1259
411
1556
411
1556
Recovery capacities are based on heater performance at 96% thermal efficiency for BTH 300A, 400A, and 95% thermal efficiency for BTH 500A.
FOREWORD
These designs comply with the current edition of the American
National Standard for Gas Water Heaters, Volume III ,
ANSI Z21.10.3 / CSA 4.3 as an automatic circulating tank water
heater, and automatic storage water heaters.
In addition to these instructions, the equipment shall be installed in
accordance with those installation regulations in force in the local
area where the installation is to be made. These shall be carefully
followed in all cases. Authorities having jurisdiction should be
consulted before installations are made.
Detailed installation diagrams are found in this manual. These
diagrams will serve to provide the installer with a reference for the
materials and methods of piping necessary. It is highly essential
that all water, gas piping and wiring be installed as shown on the
diagrams.
In the absence of local codes, the installation must comply
with the current editions of the National Fuel Gas Code,
ANSI Z223.1/NFPA 54 and the National Electrical Code,
NFPA 70 or CAN/CSA-B149.1, the Natural Gas and Propane
Installation Code and CSA C22.1, the Canadian Electrical Code. All
documents are available from the Canadian Standards Association,
8501 East Pleasant Valley Road, Cleveland, OH 44131. NFPA
documents are also available from the National Fire Protection
Association, 1 Batterymarch Park, Quincy, MA 02269.
Particular attention should be given to the installation of thermometers
at the locations indicated on the diagrams as these are necessary
for checking the proper functioning of the heater.
TABLE OF CONTENTS
Water (Potable) Heating & Space Heating........................................... 17
Heater Wiring..................................................................................17-19
OPERATION............................................................................................. 20
Sequence of Operation........................................................................ 20
ELECTRONIC CONTROL........................................................................ 20
Overview.............................................................................................. 20
Operating States.............................................................................20-21
Adjusting the Operating Set Point........................................................ 21
Changing the Display Units.................................................................. 22
Fault and Warning Conditions.........................................................22-23
Access to the Current Fault or Warning............................................... 23
Viewing the Fault History..................................................................... 24
Viewing Information About the Heater.................................................. 24
PRIOR TO START-UP REQUIRED ABILITY............................................ 25
OPERATING INSTRUCTIONS................................................................. 25
Adjustment Procedure (Initial Start-Up)..........................................25-26
Lighting Instructions............................................................................. 26
Cathodic Protection.............................................................................. 27
Precautions.......................................................................................... 27
GENERAL INFORMATION....................................................................... 27
Power Burner....................................................................................... 27
High Limit............................................................................................. 27
High Altitude Installations..................................................................... 27
MAINTENANCE....................................................................................... 27
General................................................................................................ 27
Maintenance Schedule......................................................................... 27
Flushing................................................................................................ 28
Draining................................................................................................ 28
Sediment Removal............................................................................... 28
Lime Scale Removal.......................................................................28-29
Powered Anode System....................................................................... 29
Drain Valve and Access Panels........................................................... 29
Relief Valve.......................................................................................... 29
Vent System......................................................................................... 29
INSTALLATION DIAGRAMS...............................................................30-34
Multiple Unit Installations..................................................................... 35
CHECKLIST AND SERVICE INFORMATION.......................................... 36
Burner Operational Problems............................................................... 36
Not Enough or No Hot Water............................................................... 36
Water Is Too Hot................................................................................... 36
Water Heater Makes Sounds............................................................... 36
Water Leakage is Suspected.................................................................... 36
TROUBLESHOOTING........................................................................36-38
REPLACEMENT PARTS.......................................................................... 38
LIMITED WARRANTY.............................................................................. 39
ROUGH-IN DIMENSIONS.......................................................................... 2
FOREWORD.............................................................................................. 2
FEATURES................................................................................................. 3
Water Temperature Control.................................................................3-5
Water Temperature Setpoint Adjustment Procedure.............................. 5
High Limit Switch (E.C.O.)..................................................................... 5
Dishwashing Machine Requirement....................................................... 5
Circulating Pump.................................................................................... 6
INSTALLATION INSTRUCTIONS.............................................................. 6
Required Ability...................................................................................... 6
Insulation Blankets................................................................................. 6
Locating The Heater............................................................................... 6
Clearances............................................................................................. 7
Hard Water............................................................................................. 7
Air Requirements................................................................................... 7
Mechanical Exhausting of Room Air...................................................... 7
Unconfined Space.................................................................................. 7
Confined Space...................................................................................... 7
Chemical Vapor Corrosion..................................................................... 7
Installation Requirements for the
Commonwealth of Massachusetts......................................................... 8
VENTING............................................................................................... 8-11
Vent Pipe Termination.......................................................................... 11
Direct Venting....................................................................................... 11
Direct Vent Terminal Installation...................................................... 11-12
Installation Sequence........................................................................... 12
Vertical Vent Terminal Installation........................................................ 12
Installation Sequence......................................................................12-13
Installation of Vent System................................................................... 13
Vent Pipe Preparation.......................................................................... 14
CONTROLS AND SWITCHES................................................................. 14
Blower Prover Switch........................................................................... 14
Blocked Outlet Prover Switch............................................................... 14
Blocked Inlet Prover Switch................................................................. 14
Low Gas Pressure Switch.................................................................... 14
On/Off Switch..................................................................................14-15
Hot Surface Igniter............................................................................... 15
GAS PIPING............................................................................................. 15
Connection of Gas Pipe..................................................................15-16
Purging................................................................................................. 16
Gas Meter Size - City Gases Only....................................................... 16
Gas Valves........................................................................................... 16
SYSTEM CONNECTIONS....................................................................... 16
Thermometers...................................................................................... 16
Relief Valve.......................................................................................... 16
Water Line Connections....................................................................... 16
Closed System................................................................................16-17
FEATURES
DANGER
THIS WATER HEATER IS EQUIPPED WITH AN ADJUSTABLE
THERMOSTAT TO CONTROL WATER TEMPERATURE. HOT
WATER TEMPERATURES REQUIRED FOR AUTOMATIC
DISHWASHER AND LAUNDRY USE CAN CAUSE SCALD
BURNS RESULTING IN SERIOUS PERSONAL INJURY AND/OR
DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS
VARIES WITH THE PERSON’S AGE AND TIME OF EXPOSURE.
THE SLOWER RESPONSE TIME OF CHILDREN, AGED OR
DISABLED PERSONS INCREASES THE HAZARDS TO THEM.
NEVER ALLOW SMALL CHILDREN TO USE A HOT WATER TAP,
OR TO DRAW THEIR OWN BATH WATER. NEVER LEAVE A
CHILD OR DISABLED PERSON UNATTENDED IN A BATHTUB
OR SHOWER.
IMPORTANT
IT IS REQUIRED THAT A QUALIFIED SERVICE TECHNICIAN
PERFORM THE INITIAL FIRING OF THE HEATER. AT THIS TIME
THE USER SHOULD NOT HESITATE TO ASK THE TECHNICIAN
ANY QUESTIONS WHICH HE MAY HAVE IN REGARD TO THE
OPERATION AND MAINTENANCE OF THE UNIT.
A CHECKLIST AND SERVICE INFORMATION section are included
at the rear of this manual. By using this checklist the user may
be able to make minor operational adjustments and save himself
unnecessary service calls. However, the user should not attempt
repairs which are not listed in this section.
WATER TEMPERATURE CONTROL
THE WATER HEATER SHOULD BE LOCATED IN AN AREA
WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO
SET TEMPERATURES.
The water temperature is controlled using the Temperature Control
Up/Dn Button on the Display at the front of the unit (See Figure 1).
This control utilizes two temperature probes to determine the tank
temperature. The primary temperature probe is located at the top
of the tank and the other is near the water inlet.
“AT A GLANCE” BTH 300/400/500
QUICK INSTALLATION TIPS
Horizontal Sidewall Venting
Vertical Rooftop Venting
The temperature may be adjusted from 80°F/27°C to 180°F/82°C.
The temperature was adjusted to 120°F/49°C before the heater
was shipped from the factory. It is recommended that lower water
temperatures be used to avoid the risk of scalding. It is further
recommended, in all cases, that the water temperature be set for the
lowest temperature which satisfies your hot water needs. This will
also provide the most energy efficient operation of the water heater
and minimize scale formation.
Valves for reducing point-of-use temperature by mixing cold
and hot water are available (see Figure 2). Also available are
inexpensive devices that attach to faucets to limit hot water
temperatures. Contact a licensed plumber or the local plumbing
authority.
WATER TEMPERATURE SETPOINT ADJUSTMENT
PROCEDURE
CAUTION
THE TEMPERATURE OF THE WATER AT THE TANK OUTLET
MAY NOT CORRESPOND TO THE TEMPERATURE SETPOINT
PROGRAMMED IN THE CONTROLLER. THE USER CAN EASILY
CHANGE THE TEMPERATURE SETPOINT AT ANY TIME BY USING
THE FOLLOWING PROCEDURE. IN ALL CASES, INPUT POWER
MUST BE APPLIED TO THE CONTROLLER TO PERFORM ANY
PROGRAMMING OPERATIONS.
The Operating Set Point of this water heater determines the regulated
temperature for the water in the tank. This parameter is adjusted in the
Temperature menu. Items in this menu allow you to monitor different
temperature readings in the tank along with adjusting the Operating
Set Point and Differential. To change the current programmed
temperature setpoint value, see OPERATION section for details.
FIGURE 2.
Figure 1 shows the approximate time-to-burn relationship for normal
adult skin. Short repeated heating cycles caused by small hot water
uses can cause temperatures at the point of use to exceed the
thermostat setting by up to 20°F (11C°). If you experience this type
of use, you should consider using lower temperature settings to
reduce scald hazards.
HIGH LIMIT SWITCH (E.C.O.)
The top immersion well of the dual bulb controller also contains the
high limit (energy cutoff) sensor. The high limit switch interrupts
the main burner gas flow should the water temperature reach
approximately 202°F/94°C. Should the high limit switch activate,
the water temperature must drop below 140°F/60°C before the
controller can be reset. The following is a possible reason for high
limit switch operation.
• A malfunction in the thermostatic controls would allow the gas
valve to remain open causing water temperature to exceed the
thermostat setting. The water temperature would continue to rise
until high limit switch operation.
Contact your dealer or servicer if continued high limit switch
operation occurs.
DISHWASHING MACHINE REQUIREMENT
Temperature
Setting
180°F/82°C
170°F/77°C
160°F/71°C
150°F/66°C
140°F/60°C
130°F/54°C
120°F/49°C
All dishwashing machines meeting the National Sanitation
Foundation requirements are designed to operate with water flow
pressures between 15 and 25 pounds per square inch (103 Kpa
and 173 Kpa). Flow pressures above 25 pounds per square inch
(173 Kpa), or below 15 pounds per square inch (103 Kpa), will result
in improperly sanitized dishes. Where pressures are high, a water
pressure reducing or flow regulating control valve should be used
in the 180°F (82°C) line to the dishwashing machine, and should be
adjusted to deliver water between these limits.
Time to Produce 2nd & 3rd
Degree Burns on Adult Skin
Nearly instantaneous
Nearly instantaneous
About 1/2 second
About 1-1/2 seconds
Less than 5 seconds
About 30 seconds
More than 5 minutes
The National Sanitation Foundation also recommends circulation of
180°F (82°C) water. Where this is done, the circulation should be
very gentle so that it does not cause any unnecessary turbulence
inside the water heater. The circulation should be just enough to
provide 180°F (82°C) water at the point of take-off to the dishwashing
machine. Adjust flow by means of the plug cock in the circulating
line. (See installation diagrams.)
FIGURE 1.
CIRCULATING PUMP
THE HEATER SHALL BE LOCATED OR PROTECTED SO IT IS NOT
SUBJECT TO PHYSICAL DAMAGE BY A MOVING VEHICLE.
A circulating pump is used when a system requires a circulating loop or
there is a storage tank used in conjunction with the heater. Refer to the
piping diagrams at rear of manual for electrical hookup information and
install in accordance with the current edition of the National Electrical
Code, NFPA 70 or the Canadian Electrical Code, CSA C22.1.
DO NOT LOCATE THE HEATER WHERE NOISE FROM THE
EXHAUST OR INTAKE WILL BE OBJECTIONABLE. THIS
INCLUDES LOCATIONS CLOSE TO OR ACROSS FROM
WINDOWS AND DOORS. AVOID ANCHORING THE VENT AND
INTAKE PIPES DIRECTLY TO FRAMED WALLS, FLOORS OF
CEILINGS UNLESS RUBBER ISOLATION PIPE HANGERS
ARE USED. THIS PREVENTS ANY VIBRATIONS FROM BEING
TRANSMITTED INTO THE LIVING SPACES.
All bronze circulators are recommended for used with commercial
water heaters.
Although circulators are oiled and operated by the manufacturer
some circulators must be oiled again before operated. Please refer
to manufacturer's instructions.
WARNING
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST
NEVER BE PLACED ON OR ADJACENT TO THE HEATER. OPEN
CONTAINERS OF FLAMMABLE MATERIAL SHOULD NOT BE
STORED OR USED IN THE SAME ROOM WITH THE HEATER.
INSTALLATION INSTRUCTIONS
REQUIRED ABILITY
When installing the heater, consideration must be given to
proper location. Location selected should be as close to the
intake and exhaust termination points as practicable, with
adequate air supply and as centralized with the piping system
as possible.
INSTALLATION OR SERVICE OF THIS WATER HEATER
REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED
TRADESMAN IN THE FIELD INVOLVED. PLUMBING, AIR
SUPPLY, VENTING, GAS SUPPLY AND ELECTRICAL WORK
ARE REQUIRED.
THE HEATER MUST NOT BE LOCATED IN AN AREA WHERE IT
WILL BE SUBJECT TO FREEZING.
INSULATION BLANKETS
Insulation blankets available to the general public for external use
on gas water heaters are not approved for use on your A.O. Smith
water heater. The purpose of an insulation blanket is to reduce the
standby heat loss encountered with storage tank water heaters.
Your A.O. Smith water heater meets or exceeds the ASHRAE/IES
90.1-1999 standards with respect to insulation and standby loss
requirements, making an insulation blanket unnecessary.
LOCATE IT NEAR A FLOOR DRAIN. THE HEATER SHOULD
BE LOCATED IN AN AREA WHERE LEAKAGE FROM THE
HEATER OR CONNECTIONS WILL NOT RESULT IN DAMAGE
TO THE ADJACENT AREA OR TO LOWER FLOORS OF THE
STRUCTURE.
When such locations cannot be avoided, it is recommended that
a suitable drain pan, adequately drained, be installed under the
appliance.
WARNING
Should you choose to apply an insulation blanket to this heater, you
should follow these instructions. Failure to follow these instructions
can result in fire, asphyxiation, serious personal injury or death.
WARNING
This water heater is a condensing unit and requires
a drain to be located in close proximity to allow
the condensate to drain safely. The condensate
drains from the unit at the exhaust elbow located
at the bottom of the unit. Note: It is important that
the condensate hose not be elevated above the
exhaust elbow (see Figure 3). The condensate buildup will block the exhaust outlet, which will cause
improper operation.
• Do not apply insulation to the top, or the upper 15" (38 cm) of the
water heater, as this will interfere with safe operation.
• Do not cover the temperature & pressure relief valve.
• Do not cover the instruction manual. Keep it on the side of the
water heater or nearby for future reference.
• Do obtain new labels from A.O. Smith for placement on the blanket
directly over the existing labels.
LOCATING THE HEATER
WARNING
THERE IS A RISK IN USING FUEL BURNING APPLIANCES
SUCH AS GAS WATER HEATERS IN ROOMS, GARAGES OR
OTHER AREAS WHERE GASOLINE, OTHER FLAMMABLE
LIQUIDS OR ENGINE DRIVEN EQUIPMENT OR VEHICLES ARE
STORED, OPERATED OR REPAIRED. FLAMMABLE VAPORS
ARE HEAVY AND TRAVEL ALONG THE FLOOR AND MAY BE
IGNITED BY THE HEATER’S IGNITER OR MAIN BURNER
FLAMES CAUSING FIRE OR EXPLOSION. SOME LOCAL CODES
PERMIT OPERATION OF GAS APPLIANCES IF INSTALLED
18 INCHES (46 cm) OR MORE ABOVE THE FLOOR. THIS
MAY REDUCE THE RISK IF LOCATION IN SUCH AN AREA
CANNOT BE AVOIDED.
FIGURE 3.
WARNING
DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN
UNDER WATER. IMMEDIATELY CALL A QUALIFIED SERVICE
TECHNICIAN TO INSPECT THE APPLIANCE AND TO REPLACE
ANY PART OF THE CONTROL SYSTEM AND ANY GAS CONTROL
WHICH HAS BEEN UNDER WATER.
CLEARANCES
MECHANICAL EXHAUSTING OF ROOM AIR
These heaters are approved for installation on combustible flooring
in an alcove when the minimum clearances from any combustion
construction are followed as indicated in Figure 4.
Where an exhaust fan is installed in the same room with a heater,
sufficient openings for air must be provided in the walls. UNDERSIZED
OPENINGS WILL CAUSE AIR TO BE DRAWN INTO THE ROOM
THROUGH THE HEATER’S VENTING SYSTEM, CAUSING POOR
COMBUSTION. SOOTING MAY RESULT IN SERIOUS DAMAGE
TO THE HEATER AND RISK OF FIRE OR EXPLOSION. IT CAN
ALSO CREATE A RISK OF ASPHYXIATION.
In all installations the minimum combustible clearances from any
vent piping shall be 0". Vent piping passing through a combustible
wall or ceiling must be a continuous run (no joints).
UNCONFINED SPACE
A service clearance of 24" (61 cm) should be maintained from
serviceable parts such as relief valves, thermostats, cleanout
openings, drain valves and venting connections.
In buildings of conventional frame, brick or stone construction,
unconfined spaces may provide adequate air for combustion and
ventilation.
Always disconnect electrical power before servicing the unit.
If the unconfined space is within a building of tight construction
(buildings using the following construction: weather stripping,
heavy insulation, caulking, vapor barrier, etc.), air for combustion
and ventilation must be obtained from outdoors. The installation
instructions for confined spaces in tightly constructed buildings must
be followed to ensure adequate air supply.
CONFINED SPACE
When drawing combustion air from inside a conventionally
constructed building to a confined space, such a space shall be
provided with two permanent openings, ONE IN OR WITHIN
12 INCHES (31 cm) OF THE ENCLOSURE TOP AND ONE IN OR
WITHIN 12 INCHES (31 cm) OF THE ENCLOSURE BOTTOM. Each
opening shall have a free area of at least one square inch per 1000
Btuh (2,203mm2/kW) appliances in the enclosure, but not less than
100 square inches (645 cm²).
*ILLUSTRATION OF MINIMUM COMBUSTIBLE CLEARANCES
IN AN ALCOVE.
FIGURE 4.
If the confined space is within a building of tight construction, air
for combustion and ventilation must be obtained from outdoors.
When directly communicating with the outdoors through vertical
ducts, two permanent openings, located in the above manner,
shall be provided. Each opening shall have a free area of not
less than one square inch per 4000 Btuh (551mm2/kW) of the
total input of all appliances in the enclosure. If horizontal ducts
are used, each opening shall have a free area of not less than one
square inch per 2000 Btuh (1,102mm2/kW) of the total input of all
appliances in the enclosure.
HARD WATER
Where hard water conditions exist, water softening or the threshold
type of water treatment is recommended. This will protect the
dishwashers, coffee urns, water heaters, water piping and other
equipment.
See MAINTENANCE section for details of tank cleanout procedure.
AIR REQUIREMENTS
CHEMICAL VAPOR CORROSION
KEEP APPLIANCE AREA CLEAR AND FREE OF COMBUSTIBLE
MATERIALS, GASOLINE AND OTHER FLAMMABLE VAPORS
AND LIQUIDS.
WARNING
CORROSION OF THE FLUE WAYS AND VENT SYSTEM MAY
OCCUR IF AIR FOR COMBUSTION CONTAINS CERTAIN
CHEMICAL VAPORS. SUCH CORROSION MAY RESULT IN
FAILURE AND RISK OF ASPHYXIATION.
DO NOT OBSTRUCT THE FLOW OF COMBUSTION AND
VENTILATING AIR.
Spray can propellants, cleaning solvents, refrigerator and air
conditioning refrigerants, swimming pool chemicals, calcium
and sodium chloride, waxes, and process chemicals are typical
compounds which are potentially corrosive.
WARNING
FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR
COMBUSTION AND VENTILATION. AN INSUFFICIENT SUPPLY
OF AIR WILL CAUSE RECIRCULATION OF COMBUSTION
PRODUCTS RESULTING IN CONTAMINATION THAT MAY BE
HAZARDOUS TO LIFE. SUCH A CONDITION OFTEN WILL
RESULT IN A YELLOW, LUMINOUS BURNER FLAME, CAUSING
CARBONING OR SOOTING OF THE COMBUSTION CHAMBER,
BURNERS AND FLUE TUBES AND CREATES A RISK OF
ASPHYXIATION.
PRODUCTS OF THIS SORT SHOULD NOT BE STORED NEAR
THE HEATER. ALSO, AIR WHICH IS BROUGHT IN CONTACT
WITH THE HEATER SHOULD NOT CONTAIN ANY OF THESE
CHEMICALS. IF NECESSARY, UNCONTAMINATED AIR SHOULD
BE OBTAINED FROM REMOTE OR OUTSIDE SOURCES.
INSTALLATION REQUIREMENTS FOR THE
COMMONWEALTH OF MASSACHUSETTS
EXEMPTIONS
The following equipment is exempt from 248 CMR 5.08(2)(a)1
through 4:
For all side wall terminated, horizontally vented power vent, direct
vent, and power direct vent gas fueled water heaters installed in every
dwelling, building or structure used in whole or in part for residential
purposes, including those owned or operated by the Commonwealth
and where the side wall exhaust vent termination is less than seven
(7) feet above finished grade in the area of the venting, including
but not limited to decks and porches, the following requirements
shall be satisfied:
1. The equipment listed in Chapter 10 entitled “Equipment Not
Required To Be Vented” in the most current edition of NFPA 54
as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled
equipment installed in a room or structure separate from the
dwelling, building, or structure used in whole or in part for
residential purposes.
INSTALLATION OF CARBON MONOXIDE DETECTORS
MANUFACTURER REQUIREMENTS - GAS EQUIPMENT
VENTING SYSTEM PROVIDED
At the time of installation of the side wall horizontal vented gas
fueled equipment, the installing plumber or gasfitter shall observe
that a hard wired carbon monoxide detector with an alarm and
battery back-up is installed on the floor level where the gas
equipment is to be installed. In addition, the installing plumber or
gasfitter shall observe that a battery operated or hard wired carbon
monoxide detector with an alarm is installed on each additional
level of the dwelling, building or structure served by the sidewall
horizontal vented gas fueled equipment. It shall be the responsibility
of the property owner to secure the services of qualified licensed
professionals for the installation of hard wired carbon monoxide
detectors.
When the manufacturer of Product Approved side wall horizontally
vented gas equipment provides a venting system design or venting
system components with the equipment, the instructions provided
by the manufacturer for installation of the equipment and the venting
system shall include:
1. Detailed instructions for the installation of the venting system
design or the venting system components; and
2. A complete parts list for the venting system design or venting
system.
In the event that the side wall horizontally vented gas fueled
equipment is installed in a crawl space or an attic, the hard wired
carbon monoxide detector with alarm and battery back-up may be
installed on the next adjacent floor level.
MANUFACTURER REQUIREMENTS - GAS EQUIPMENT
VENTING SYSTEM NOT PROVIDED
When the manufacturer of a Product Approved side wall horizontally
vented gas fueled equipment does not provide the parts for venting
the flue gases, but identifies “special venting systems,” the following
requirements shall be satisfied by the manufacturer:
In the event that the requirements of this subdivision can not be
met at the time of completion of installation, the owner shall have
a period of thirty (30) days to comply with the above requirements
provided that during said thirty (30) day period, a battery operated
carbon monoxide detector with an alarm shall be installed.
1. The referenced “special venting system” instructions shall
be included with the appliance or equipment installation
instructions; and
APPROVED CARBON MONOXIDE DETECTORS
Each carbon monoxide detector as required in accordance with the
above provisions shall comply with NFPA 720 and be ANSI/UL 2034
listed and CSA certified.
2. The “special venting systems” shall be Product Approved by the
Board, and the instructions for that system shall include a parts
list and detailed installation instructions.
SIGNAGE
A copy of all installation instructions for all Product Approved
side wall horizontally vented gas fueled equipment, all venting
instructions, all parts lists for venting instructions, and/or all
venting design instructions shall remain with the appliance or
equipment at the completion of the installation.
A metal or plastic identification plate shall be permanently mounted
to the exterior of the building at a minimum height of eight (8) feet
above grade directly in line with the exhaust vent terminal for the
horizontally vented gas fueled heating appliance or equipment.
The sign shall read, in print size no less than one-half (1/2) inch
in size, “GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL
OBSTRUCTIONS.”
VENTING
WARNING
THE INSTRUCTIONS IN THIS SECTION ON VENTING MUST
BE FOLLOWED TO AVOID CHOKED COMBUSTION OR
RECIRCULATION OF FLUE GASES. SUCH CONDITIONS CAUSE
SOOTING OR RISKS OF FIRE AND ASPHYXIATION.
INSPECTION
The state or local gas inspector of the side wall horizontally vented
gas fueled equipment shall not approve the installation unless, upon
inspection, the inspector observes carbon monoxide detectors and
signage installed in accordance with the provisions of 248 CMR
5.08(2)(a) 1 through 4.
Heater must be protected from freezing downdrafts during
shutdown periods.
US DIRECT VENT
CAUTION
TO PREVENT EXHAUSTING PRODUCTS FROM CIRCULATING TO THE
AIR INTAKE IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL
DISTANCE BETWEEN THESE TWO TERMINALS IS RECOMMENDED.
CANADIAN DIRECT VENT
FIGURE 5.
US HORIZONTAL VENT
CAUTION
TO PREVENT EXHAUSTING PRODUCTS FROM CIRCULATING TO THE
AIR INTAKE IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL
DISTANCE BETWEEN THESE TWO TERMINALS IS RECOMMENDED.
CANADIAN HORIZONTAL VENT
FIGURE 6.
10
WARNING
WARNING
NEVER OPERATE THE HEATER UNLESS IT IS VENTED TO THE
OUTDOORS AND HAS ADEQUATE AIR SUPPLY TO AVOID RISKS OF
IMPROPER OPERATION, FIRE, EXPLOSION OR ASPHYXIATION.
WHEN THE UNIT IS TO BE SETUP AS A DIRECT VENT,
THE INTAKE GUARD AND THE BALANCE PLATE MUST BE
REMOVED. THE INLET VENT PIPE MAY THEN BE GLUED TO
THE AIR INTAKE (see Figure 8) PROVIDED ON THE UNIT.
VENT PIPE TERMINATION
NOTE: Before installing venting, determine place of vent pipe
termination. See Figure 5 and 6 before proceeding.
CAUTION
DO NOT TERMINATE THE VENTING WHERE NOISE FROM
THE EXHAUST OR INTAKE WILL BE OBJECTIONABLE. THIS
INCLUDES LOCATIONS CLOSE TO OR ACROSS FROM
WINDOWS AND DOORS. AVOID ANCHORING THE VENT AND
INTAKE PIPES DIRECTLY TO FRAMED WALLS, FLOORS OR
CEILINGS UNLESS RUBBER ISOLATION PIPE HANGERS
ARE USED. THIS PREVENTS ANY VIBRATIONS FROM BEING
TRANSMITTED INTO THE LIVING SPACES.
IMPORTANT
The vent system must terminate so that proper clearances are
maintained as cited in local codes or the current editions of the
National Fuel Gas Code, ANSI Z223.1/NFPA 54 or the Natural Gas
and Propane Installation Code, CAN/CSA-B149.1.
Do not terminate the exhaust vent terminal over public area where
condensate or vapor can cause nuisance or hazard.
Plan the vent system layout so that proper clearances are maintained
from plumbing and wiring.
Vent pipes serving power vented appliances are classified by building
codes as "vent connectors". Required clearances from combustible
materials must be provided in accordance with information in this
manual under LOCATION OF HEATER and CLEARANCES, and
with National Fuel Gas Code and local Codes.
FIGURE 8.
DIRECT VENT TERMINAL INSTALLATION
IMPORTANT
IMPORTANT
4" VENT AND INTAKE TERMINALS ARE PROVIDED FOR
NEW INSTALLATIONS. FOR REPLACEMENT OF PREVIOUS
BTH 300 AND 400 WITH 3" TERMINALS, THE 4" TERMINALS
ARE RECOMMENDED, BUT THE EXISTING 3" VENT/INTAKE
TERMINALS ARE PERMITTED.
Plan the layout of the vent system backwards from the vent
termination to the appliance.
WARNING
USE ONLY THE VENT TERMINALS SUPPLIED WITH THIS UNIT.
TERMINATION OF A VENT SYSTEM WITH A DEVICE OTHER THAN
THE SUPPLIED VENT TERMINATIONS WILL AFFECT SYSTEM
PERFORMANCE AND RESULT IN A SAFETY HAZARD.
NOTE: TO PREVENT EXHAUSTING PRODUCTS FROM
CIRCULATING TO THE AIR INTAKE IN WINDY/COLD AREAS,
THE MAXIMUM PRACTICAL DISTANCE BETWEEN THESE TWO
TERMINALS IS RECOMMENDED.
DIRECT VENTING
IMPORTANT
The air intake provided on the unit contains an intake guard, see
Figure 7.
3"x 4" PVC REDUCER WITH INTAKE SCREEN
WHEN LOCATING THE TERMINALS ON A SIDEWALL, THE
FOLLOWING SPECIFICATIONS PERTAINING TO TERMINAL
LOCATION MUST BE FOLLOWED.
FIGURE 7.
1. The intake vent terminal and the exhaust vent terminal must
terminate on the same exterior wall and must be located at
a minimum of 24" (61cm) from the vertical centerline of the
exhaust vent terminal (see Figure 9). In colder climates
increasing the 24" (61cm) minimum to 48" (122cm) will
reduce possibility of frost over from side winds blowing
exhaust vapors to the air intake of the direct the vent and is
recommended for Canada.
11
Slide the pipe through the wall and insert into coupling on the
other side of the wall, making sure that the vent terminal ends
up pointed in the correct position. See Figure 10.
2. The horizontal centerline of the intake vent terminal may not be
located lower than the horizontal centerline of the exhaust vent
terminal (see Figure 9).
EXHAUST VENT TERMINAL
FIGURE 9.
INSTALLATION SEQUENCE
For installations in the City of Los Angeles, California Category IV
PVC Pipe such as that manufactured by Brownline Pipe Company,
must be used as vent pipe material.
CAUTION
Vent terminals supplied with the heater must be used.
NOTE: BEFORE BEGINNING INSTALLATION OF ANY VENT
PIPE READ THE VENT PIPE MANUFACTURER'S INSTALLATION
INSTRUCTIONS.
INTAKE VENT TERMINAL
1. After the points of termination have been determined, use the
cover plates as templates to mark the holes for the vent pipes
to be inserted through the wall. BEWARE OF CONCEALED
WIRING AND PIPING INSIDE OF WALL.
FIGURE 10.
VERTICAL VENT TERMINAL INSTALLATION
IMPORTANT
2. If the vent terminals are being installed on the outside of a finished
wall, it may be easier to mark both the inside and outside wall.
Align the holes by drilling a hole through the center of the template
from the inside through to the outside. The template can now be
positioned on the outside wall using the drilled holes as a centering
point for the template.
WHEN TERMINATING THROUGH A ROOF, THE FOLLOWING
SPECIFICATIONS PERTAINING TO TERMINAL LOCATION MUST
BE FOLLOWED.
1. Proper support must be provided for all pipe protruding through
the roof.
3. A) MASONRY SIDE WALLS
Chisel an opening approximately 1/2" (1.3 cm) larger than the
marked circle.
2. The vertical roof terminations should be sealed with a plumbing
roof boot or equivalent flashing.
B) WOODEN SIDE WALLS
Drill a pilot hole approximately one quarter inch outside of the
marked circle. This pilot hole is used as a starting point for a
saws-all or sabre saw blade. Cut around the marked circle staying
approximately one quarter inch outside of the line. (This will allow
the vent pipe to easily slide through the opening. The resulting
gap will be covered by the vent terminal cover plates.) Repeat
this step on the inside wall if necessary.
3. The intake vent termination and the exhaust vent termination
must penetrate the same side of roof.
4. The center line of the intake vent termination and the center
line of the exhaust vent termination must be no closer than
24" (61cm).
5. The intake vent terminal and the exhaust vent terminal must be
oriented facing downward and the same direction.
4. Cut a length of PVC pipe about 3.5" (8.9 cm) longer than the wall
thickness at the opening.
The specifications are displayed in Figure 11.
5. Glue the intake vent terminal to the section of the pipe.
NOTE: Exhaust vent terminal is installed using the same procedure.
6. Slide the wall plate over the pipe to stop against intake vent terminal.
INSTALLATION SEQUENCE
7. Place a bead of caulking (not supplied) around the gap between
the pipe and the wall. Place some of the caulking on the back of
the plate to hold it against the wall after installation.
NOTE: BEFORE BEGINNING INSTALLATION OF ANY VENT
PIPE, READ “VENT PIPE PREPARATION” SECTION.
8. If the vent pipe is installed up to the wall, with a coupling on the
end against the wall opening, the pipe with the vent terminal
can be prepared for gluing before inserting through the wall.
1. After the points of termination have been determined, use the
cover plates as templates to mark the holes for the vent pipes to
be inserted through the roof.
12
2. Drill a pilot hole approximately 1/4" (6 mm) outside of the marked
circle. This pilot hole is used as a starting point for a sawsall or sabre saw blade. Cut around the marked circle staying
approximately one quarter inch outside the line. (This will allow
the vent pipe to easily slide through the opening). The resulting
gap will be covered by the roof boot/flashing.
3. The unit is certified to a minimum amount of 4-inch pipe for
the exhaust venting arrangement of 15-equivalent feet. This is
the minimum amount of pipe required for the exhaust venting
arrangement. The intake venting arrangement is certified to use
a minimum of 0-equivalent feet of 4-inch PVC pipe.
3. Suspend the pipe through center of hole using proper support.
IMPORTANT
When multiple units are direct vented through a wall (4-inch venting),
all intake vent terminals should be no lower than the highest exhaust
vent terminal.
4. Slide roof boot or equivalent flashing over pipe and secure roof
boot equivalent flashing to roof.
5. Seal around flashing.
6. Terminate intake terminal and exhaust vent terminal facing down.
See Figure 11.
NOTE: This unit can be vented using only PVC (Class 160, ASTM
D-2241 Schedule 40, ASTM D-1785 ; or Cellular Core Schedule
40 DWV, ASTM F-891) , Schedule 40 CPVC (ASTM F-411), or ABS
(ASTM D-2661) pipe. The fittings, other than the TERMINATIONS
should be equivalent to PVC-DWV fittings meeting ASTM D-2665
(Use CPVC fittings, ASTM F-438 for CPVC pipe and ABS fittings,
ASTM D-2661/3311 for ABS pipe. If CPVC or ABS pipe and fittings
are used, then the proper cement must be used for all joints, including
joining the pipe to the Termination (PVC Material). PVC Materials
should use ASTM D-2564 Grade Cement; CPVC Materials should
use ASTM F-493 Grade Cement and ; ABS Materials should use
ASTM D-2235 Grade Cement.
NOTE: for Water Heaters in locations with high ambient
temperatures (above 100°F or 38°C) and/or insufficient dilution air,
it is recommended that CPVC or ABS pipe and fittings (MUST USE
SUPPLIED VENT TERMINAL) be used.
FIGURE 11.
INSTALLATION OF VENT SYSTEM
WARNING
THE OPTIONAL INTAKE VENTING ARRANGEMENT AND THE
EXHAUST VENTING ARRANGEMENT MUST BE INSTALLED TO
RUN DIRECTLY TO THE OUTDOORS AND NOT IN ANY WAY BE
CONNECTED TO ANOTHER VENTING SYSTEM (I.E. FURNACE,
DRYERS OR SPACE HEATERS). IT IS CRUCIAL THAT THE
VENTING ARRANGEMENT BE KEPT SEPARATE FROM OTHER
VENTING SYSTEMS. IF THIS WARNING IS IGNORED, AND THE
SYSTEM IS VENTED INCORRECTLY, IT MAY CAUSE IMPROPER
OPERATION, FIRE, EXPLOSION, OR ASPHYXIATION.
1. Plan the route of the vent system from the vent termination to the
planned location of the appliance. Layout the total vent system
to use the minimum of vent pipe and elbows possible.
5. It is important that condensate not be allowed to buildup in the
exhaust vent pipe. To prevent this from happening the pipe should
be installed with a slight, 1/8 inch (3mm) per 5 feet (152 cm) of
pipe maximum downward slope.
6. The vent system should be supported every 5 feet (152 cm) of vertical
run and every 3 feet (91cm) of horizontal run of vent pipe length.
NOTE: Stress levels in the pipe and fittings can be significantly
increased by improper installation. If rigid pipe clamps are used to
hold the pipe in place, or if the pipe cannot move freely through a
wall penetration, the pipe may be directly stressed, or high thermal
stresses may be formed when the pipe heats up and expands. Install
accordingly to minimize such stresses.
2. This unit is certified for the use of 4-inch PVC pipe for venting.
The maximum length of 70-equivalent feet of 4-inch PVC pipe
may be used for the intake venting arrangement and a maximum
length of 70-equivalent feet of 4-inch PVC pipe may be used on
the exhaust venting arrangement. If the supply gas pressure
(dynamic) is set between 7" wc - 9" wc, the maximum allowed
length is 80 equivalent feet for both air intake and exhaust venting.
The maximum number of 90 degree elbows for the 4-inch venting
is six (6) in the intake and six (6) on the exhaust. A 90 degree
elbow is equal to five (5) equivalent feet of 4-inch pipe. One 90
degree elbow is equaled to two 45 degree elbows.
INLET VIEW
Table 2. VENT LENGTH TABLE
Number
of 90°
Elbows
ONE (1)
TWO (2)
THREE (3)
FOUR (4)
FIVE (5)
SIX (6)
Maximum
Feet. of Pipe 65'
60'
55'
50'
45'
40'
4" PVC
Maximum
Meters of Pipe
19.7 m
18.2 m
16.7 m
15.2 m
13.6 m
12.1 m
OUTLET VIEW
FIGURE 12.
13
VENT PIPE PREPARATION
contacts are normally open. When the fan increases the pressure
in the burner, the pressure switch will allow the electrical contacts
to close. The pressure switch is connected to the burner tap by a
piece of tygon tubing. This tubing must be connected in order for
the switch to change the electrical contacts. The controller requires
that the electrical contacts on this air flow switch be open before it
will allow the blower to come on. See Figure 13.
1. INITIAL PREPARATION
A. Make sure the solvent cement you are planning to use is
designed for the specific application you are attempting.
B. Know the physical and chemical characteristics and limitations
of the PVC, PVC cellular core, ABS or CPVC piping materials
that you are about to use.
C. Know the reputation of your pipe and cement manufacturer
and their products.
D. Know your own qualifications or those of your contractor. The
solvent welding technique of joining PVC, PVC cellular core,
ABS or CPVC pipe is a specialized skill just as any other pipe
fitting technique.
The Blocked Outlet Prover Switch is set up to shut the unit off when
a build-up of positive pressure in the exhaust vent pipe occurs.
This switch is a positive pressure switch that requires an increase
in pressure to change the electrical contacts from normally closed
to open. When this switch prevents the unit from igniting, most
likely the exhaust is blocked by some means. Check to see if the
condensate is allowed to flow freely from the exhaust elbow and
for obstructions in the exhaust venting and exhaust vent terminal.
See Figure 13.
E. Closely supervise the installation and inspect the finished
job before start-up.
F. Contact the manufacturer, supplier, or competent consulting
agency if you have any questions about the application or
installation of PVC, PVC cellular core, ABS or CPVC pipe.
G. Take the time and effort to do a professional job. Shortcuts will
only cause you problems and delays in start-up. The majority
of failures in these systems are the result of shortcuts and/or
improper joining techniques.
2.
BLOCKED OUTLET PROVER SWITCH
BLOCKED INLET PROVER SWITCH
The Blocked Inlet Prover Switch is set up to shut the unit off when
a build-up of negative pressure in the intake vent pipe occurs. This
switch is a negative pressure switch that requires an increase in
negative pressure to change the electrical contacts from normally
closed to open. The switch is connected to the pressure tap on
the flange connected to the inlet of the blower. When this switch
prevents the unit from igniting, most likely the intake is blocked by
some means. Check to see if there is no more than seventy (70)
equivalent feet (24.8m) of four inch PVC vent pipe on the intake. Also
verify that the intake and intake vent terminal is free of obstructions
that may prevent air from entering the unit. See Figure 13.
SELECTION OF MATERIALS
PRIMER
It is recommended that Tetrahydrofuran (THF) be used to prepare the
surfaces of pipe and fittings for solvent welding. Do not use water, rags,
gasoline or any other substitutes for cleaning PVC cellular core, ABS or
CPVC surfaces. A chemical cleaner such as MEK may be used.
LOW GAS PRESSURE SWITCH
The Low Gas Switch (LGS) is a single-pole, normally open pressure
switch that will close its contacts when a rising pressure of 4.6 in.
W.C. (1.25 Kpa) is encountered. The contacts will open when the
pressure falls below the fixed set point of 4.6 in. W.C. (1.25 Kpa)
The LGS monitors the gas supply pressure to the heater. If the
gas supply falls below 4.6 in. W.C. (1.25 Kpa), the main burner is
extinguished (if heater is running) or the heater will not start up.
NOTE: LOW GAS SWITCH IS LOCATED ON INLET SIDE OF GAS
VALVE. See Figure 13.
CEMENT
The cement should be a bodied cement of approximately 500 to
1600 centipoise viscosity containing 10-20% (by weight) virgin PVC
material solvated with tetrahydrofuran (THF). Small quantities of
dimethyl formamide (DMF) may be included to act as a retarding
agent to extend curing time. Select the proper cement; Schedule 40
cement should be used for Schedule 40 pipe. Never use all purpose
cements, commercial glues and adhesives or ABS cement to join
PVC or CPVC pipe and fittings.
SAFETY PRECAUTION: PRIMERS AND CEMENTS ARE
EXTREMELY FLAMMABLE AND MUST NOT BE STORED OR
USED NEAR HEAT OR OPEN FLAME. ALSO, USE ONLY IN A
WELL-VENTILATED AREA.
CONTROLS AND SWITCHES
The BTH-300, 400 & 500 are equipped with four pressure switches.
These switches are essential to the safe and proper operation of the
unit. All switches are wired in series. The controller is set up to shut
the unit down whenever there is a failure of any of the switches. It
is important to understand the purpose of each switch.
FIGURE 13.
BLOWER PROVER SWITCH
ON/OFF SWITCH
The Blower Prover Switch is provided on the heater to verify that
the fan is operating. It is a positive pressure switch whose electrical
The ON/OFF Switch is a single-pole, single-throw rocker switch. This
switch provides 120VAC from the line source to the heater.
14
CAUTION
THE WATER HEATER IS POLARITY SENSITIVE. BEFORE
APPLYING ELECTRICITY TO THIS HEATER BE CERTAIN THAT
SUPPLY NEUTRAL WIRE TO GROUND CHECK INDICATES ZERO
VOLTAGE.
HOT SURFACE IGNITER
The Hot Surface Igniter is a device that ignites the main burner by
high temperature (>1800°F or >982°C). When 120VAC is applied
to the igniter, sufficient heat is generated to ignite the main burner.
Although improvements have been made to strengthen the igniter,
it is fragile and care must be taken when handling the igniter to
prevent breakage.
GAS PIPING
Contact your local gas service company to ensure that adequate
gas service is available and to review applicable installation codes
for your area.
Size the main gas line in accordance with Table 3. The figures
shown are for straight lengths of pipe at 0.5 in. W.C. (125Pa)
pressure drop, which is considered normal for low pressure
systems Note that fittings such as elbows and tees will add to the
pipe pressure drop.
CAUTION
DO NOT USE FLEXIBLE GAS PIPING.
TABLE 3. MAXIMUM CAPACITY OF PIPE IN CUBIC FEET OF GAS
PER HOUR (Based upon a Pressure Drop of 0.5 inch Water Column
and 0.6 Specific Gravity Gas and max. gas pressure of 0.5 psig).
LENGTH
NORMAL IRON PIPE SIZES (INCHES)
IN
INPUT IN THOUSANDS BTU/HR
FEET
1 1/4"
1 1/2"
2"
2 1/2"
3"
10
1400
2100
3960
6300
11000
20
950
1460
2750
4360
7700
30
770
1180
2200
3520
6250
40
660
990
1900
3000
5300
50
580
900
1680
2650
4750
60
530
810
1520
2400
4300
70
490
750
1400
2250
3900
80
460
690
1300
2050
3700
90
430
650
1220
1950
3450
100
400
620
1150
1850
3250
125
360
550
1020
1650
2950
150
325
500
950
1500
2650
175
300
460
850
1370
2450
200
430
800
1280
2280
LENGTH
IN
METERS 1 1/4"
3.0
410
6.1
278
9.1
225
12.2
193
15.2
170
18.3
155
21.3
143
24.4
135
27.4
126
30.5
117
38.1
105
45.7
95
53.3
88
61.0
NORMAL IRON PIPE SIZES (INCHES)
INPUT IN KW
1 1/2"
2"
2 1/2"
3"
615
1160
1845
3221
428
805
1277
2255
346
644
1031
1830
290
556
878
1552
264
492
776
1391
237
445
703
1259
220
410
659
1142
202
381
600
1083
190
357
571
1010
182
337
542
952
161
299
483
864
146
278
439
776
135
249
401
717
126
234
375
688
4"
23000
15800
12800
10900
9700
8800
8100
7500
7200
6700
6000
5500
5000
4600
4"
6735
4626
3748
3192
2840
2577
2372
2196
2108
1962
1757
1610
1464
1347
WARNING
THE HEATER IS NOT INTENDED FOR OPERATION AT HIGHER
THAN 11.0" WATER COLUMN (2.74 Kpa) FOR NATURAL GAS AND
14.0" W.C. (3.49kPa) FOR PROPANE GAS SUPPLY PRESSURE.
HIGHER GAS SUPPLY PRESSURES REQUIRE SUPPLEMENTAL
REDUCING SERVICE REGULATION. EXPOSURE TO HIGHER
GAS SUPPLY PRESSURE MAY CAUSE DAMAGE TO THE GAS
CONTROLS WHICH COULD RESULT IN FIRE OR EXPLOSION.
IF OVERPRESSURE HAS OCCURRED SUCH AS THROUGH
IMPROPER TESTING OF GAS LINES OR EMERGENCY
MALFUNCTION OF THE SUPPLY SYSTEM THE GAS VALVE
MUST BE CHECKED FOR SAFE OPERATION. MAKE SURE THAT
THE OUTSIDE VENTS ON THE SUPPLY REGULATORS AND THE
SAFETY VENT VALVES ARE PROTECTED AGAINST BLOCKAGE.
THESE ARE PARTS OF THE GAS SUPPLY SYSTEM, NOT THE
HEATER. VENT BLOCKAGE MAY OCCUR DURING ICE STORMS.
IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING
FROM CONTAMINANTS IN THE GAS WAYS. SUCH FOULING
MAY CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.
IF COPPER SUPPLY LINES ARE USED THEY MUST BE
INTERNALLY TINNED AND CERTIFIED FOR GAS SERVICE.
BEFORE ATTACHING THE GAS LINE BE SURE THAT ALL GAS
PIPE IS CLEAN ON THE INSIDE.
TO TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS
SUPPLY LINE, A DIRT LEG (SOMETIMES CALLED A SEDIMENT
TRAP OR DRIP LEG) MUST BE INCORPORATED IN THE PIPING
(SEE FIG. 14). THE DIRT LEG MUST BE READILY ACCESSIBLE
AND NOT SUBJECT TO FREEZING CONDITIONS. INSTALL IN
ACCORDANCE WITH RECOMMENDATIONS OF SERVING GAS
SUPPLIERS. REFER TO THE NATIONAL FUEL GAS CODE NFPA
54 OR THE NATURAL GAS AND PROPANE INSTALLATION
CODE CAN/CSA-B149.1.
FIGURE 14.
CONNECTION OF GAS PIPE
1. When connecting gas pipe to unit, apply wrench to flange only.
Note: Do not use wrench on gas valve or gas bracket.
2. PERFORM THE GAS LEAK TEST ANY TIME WORK IS DONE
ON A GAS SYSTEM TO AVOID THE POSSIBILITY OF FIRE OR
EXPLOSION WITH PROPERTY DAMAGE, PERSONAL INJURY
OR LOSS OF LIFE.
The Gas Leak Test is performed as follows: Paint pipe connections
upstream of gas control with a rich soap and water solution to test
for leaks before operating main burner. Bubbles indicate gas leak.
To stop leak, tighten pipe connections. After piping connections are
checked, turn on main burner. With main burner in operation, paint
pipe joints (including flanges), pilot gas tubing connections and
control inlet and outlet with rich soap and water solution. Bubbles
indicate gas leak. To stop leak, tighten flange screws, joints and pipe
connections. Replace part if leak can’t be stopped.
15
RELIEF VALVE
To prevent damage, care must be taken not to apply too much torque
when attaching gas supply pipe to gas valve inlet.
This heater is equipped with an approved temperature and pressure
relief valve. ASME ratings cover pressure relief. CSA ratings cover
release rate with temperature actuation.
Apply joint compounds (pipe dope) sparingly and only to the
male threads of pipe joints. Do not apply compound to the first
two threads. Use compounds resistant to the action of liquefied
petroleum gases.
FOR SAFE OPERATION OF THE WATER HEATER, THE RELIEF
VALVE(S) MUST NOT BE REMOVED OR PLUGGED.
DISCONNECT THE APPLIANCE AND ITS MANUAL GAS
SHUTOFF VALVE FROM THE GAS SUPPLY PIPING SYSTEM
DURING ANY SUPPLY PRESSURE TESTING EXCEEDING 1/2
PSIG (3.45Kpa). GAS SUPPLY LINE MUST BE CAPPED WHEN
DISCONNECTED FROM THE HEATER. FOR TEST PRESSURES
OF 1/2 PSIG (3.45Kpa) OR LESS, THE APPLIANCE NEED NOT
BE DISCONNECTED, BUT MUST BE ISOLATED FROM THE
SUPPLY PRESSURE TEST BY CLOSING THE MANUAL GAS
SHUTOFF VALVE.
In addition to the appliance relief valve, each remote storage tank
which may be used in conjunction with this appliance shall also be
installed with a properly sized, rated and approved temperature
(ANSI) and pressure (ASME) relief valve(s). This relief valve shall
comply with the standard for relief valves and automatic gas shutoff
devices for hot water supply systems. ANSI Z21.22-CSA 4.4.
Your local code authority may have other specific relief valve
requirements.
BEFORE PLACING THE HEATER IN OPERATION, CHECK FOR
GAS LEAKAGE. USE SOAP AND WATER SOLUTION OR OTHER
MATERIAL ACCEPTABLE FOR THE PURPOSE OF LOCATING
GAS LEAKS. DO NOT USE MATCHES, CANDLES, FLAME OR
OTHER SOURCES OF IGNITION FOR THIS PURPOSE.
WARNING
THE PURPOSE OF A RELIEF VALVE IS TO AVOID EXCESSIVE
PRESSURE OR TEMPERATURE INTO THE STEAM RANGE,
WHICH MAY CAUSE SCALDING AT FIXTURES, TANK EXPLOSION,
SYSTEM OR HEATER DAMAGE. NO VALVE IS TO BE PLACED
BETWEEN THE RELIEF VALVE AND THE TANK.
PURGING
PURGING SHOULD BE PERFORMED BY PERSONS EXPERIENCED
IN THIS TYPE OF GAS SERVICE. TO AVOID RISK OF FIRE OR
EXPLOSION, PURGE DISCHARGE MUST NOT ENTER CONFINED
AREAS OR SPACES WHERE IGNITION CAN OCCUR. THE AREA
MUST BE WELL VENTILATED AND ALL SOURCES OF IGNITION
MUST BE INACTIVATED OR REMOVED.
A DRAIN LINE MUST BE CONNECTED TO THE RELIEF VALVE
TO DIRECT DISCHARGE TO A SAFE LOCATION TO AVOID
SCALDING OR WATER DAMAGE. THIS LINE MUST NOT BE
REDUCED FROM THE SIZE OF THE VALVE OUTLET AND MUST
NOT CONTAIN VALVES OR RESTRICTIONS, NOR SHOULD IT BE
LOCATED IN FREEZING AREAS. DO NOT THREAD OR CAP THE
END OF THIS LINE. RESTRICTED OR BLOCKED DISCHARGE
WILL DEFEAT THE PURPOSE OF THE VALVE AND IS UNSAFE.
THE DISCHARGE LINE SHALL BE INSTALLED TO ALLOW
COMPLETE DRAINAGE OF BOTH THE VALVE AND LINE.
GAS METER SIZE - CITY GASES ONLY
WATER LINE CONNECTIONS
Be sure that the gas meter has sufficient capacity to supply the full
rated gas input of the water heater as well as the requirements of
all other gas fired equipment supplied by the meter. If the gas meter
is too small, ask the gas company to install a larger meter having
adequate capacity.
This manual provides detailed installation diagrams (see back
section of this manual) for typical methods of application for the
water heaters.
Gas line purging is required with new piping or systems in which
air has entered.
CAUTION
The water heater may be installed by itself, or with a separate storage
tank. When used with a separate storage tank, the circulation may be
either by gravity or by means of circulating pump. When a circulating
pump is used, it is important to note that the flow rate should be slow
so that there will be a minimum of turbulence inside the heater.
GAS VALVES
WARNING
SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL
TO SHUT OFF, TURN OFF THE MANUAL GAS CONTROL VALVE
TO THE APPLIANCE.
CLOSED SYSTEM
CAUTION
SYSTEM CONNECTIONS
A closed system will exist if a check valve (without bypass), pressure
reducing valve (without bypass), or a water meter (without bypass) is
installed in the cold water line between the water heater and street
main (or well).
The system installation must conform to these instructions and to
the local code authority having jurisdiction. Good practice requires
that all heavy piping be supported.
Excessive pressure may develop causing premature tank failure or
intermittent relief valve operation. This type of failure is not covered
by the limited warranty. An expansion tank or a similar device may
be required in the inlet supply line between the appliance and the
meter or valve to compensate for the thermal expansion of water
under supply pressure.
THERMOMETERS (Not Supplied)
Thermometers should be obtained and field installed as shown in
the installation diagrams.
Thermometers are installed in the system as a means of detecting
the temperature of the outlet water supply.
If a water heater is installed in a closed water system, check local
16
codes or contact the water supplier or local plumbing inspector on
how to control this situation.
WATER (POTABLE) HEATING AND SPACE HEATING
1. All piping components connected to this unit for space heating
applications shall be suitable for use with potable water.
2. Toxic chemicals, such as those used for boiler treatment, shall
NEVER be introduced into this system.
3. This unit may never be connected to any existing heating system
or component(s) previously used with non-potable water heating
appliance.
4. When the system requires water for space heating at temperatures
higher than required for domestic water purposes, a tempering
valve must be installed. Please refer to installation diagrams
on pages 30 through 35 in back of manual for suggested piping
arrangements.
HEATER WIRING
IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THE
APPLIANCE MUST BE REPLACED, IT MUST BE REPLACED
WITH 105°C OR ITS EQUIVALENT, EXCEPT IN THE BURNER
HOUSING. IN THIS CASE USE 200°C WIRE.
THE COMPUTER CONTROL REQUIRES A SOURCE OF STABLE
CLEAN ELECTRICITY FOR PROPER OPERATION. INSTALLING
THE HEATER ON A BRANCH CIRCUIT THAT HAS ELECTRONIC
NOISE, IS SUBJECT TO FLUCTUATIONS IN VOLTAGE LEVEL
OR HAS AN APPLIANCE WHICH GENERATES EMF OF
RFI INTERFERENCE CAN CAUSE THE CONTROLLER TO
MALFUNCTION. A HIGH QUALITY POWER CONDITIONER
MUST BE INSTALLED IF THE ABOVE CONDITIONS EXIST.
MALFUNCTIONS CAUSED BY A POOR ELECTRICAL SUPPLY
ARE NOT COVERED UNDER YOUR WARRANTY.
The controller is wired to the heater as shown in figures 15 & 16. The
model and rating plate provides the electrical information needed to
size the complete heater branch supply.
All electrical work must be installed in accordance with the National
Electrical Code, NFPA 70 or the Canadian Electrical Code, CSA
C22.1 and local requirements.
When installed, the appliance must be electrically grounded in
accordance with local codes or, in the absence of local codes,
with the National Electrical Code, ANSI/NFPA 70 or the Canadian
Electrical Code, CSA C22.1.
DO NOT ENERGIZE THE BRANCH CIRCUIT BEFORE THE
HEATER TANK IS FILLED WITH WATER.
NOTE: This controller is Polarity Sensitive. If the Hot and Neutral
Supply Voltage is reversed, the controller will not sense flame. Verify
polarity before connecting the unit.
17
BTH 300 WIRING DIAGRAM
FIGURE 15.
18
BTH 400 AND 500 WIRING DIAGRAM
FIGURE 16.
19
OPERATION
inside the tank. The second temperature on this screen is the
Operating Set Point. The Operating Set Point is the temperature
at which the water heater will maintain the water inside the tank.
The third line on the screen is a text description of the Operational
State of the water heater (please see Operating States for more
details).
SEQUENCE OF OPERATION
Typical Control/Appliance Operating Sequence
1. When the control is powered, it should display the unit model,
water temperature, setting temperature and heater status.
2. If the control determines that the actual water temperature inside
the tank is below the programmed temperature setpoint less the
differential, a call for heat is activated.
3. The control then performs selected system diagnostic checks.
This includes confirming the proper state of the air/gas switches
and ECO limit device.
4. If all checks are successfully passed, the combustion blower is
energized for the pre-purge cycle.
5. When the pre-purge cycle is complete, power is applied to the
ignitor element for the ignitor warm-up period.
6. At the conclusion of the igniter warm-up period, the gas valve
will open, allowing gas to enter the burner chamber.
7. The igniter will remain on for a short predetermined time period,
then will be turned off.
8. The control will monitor the flame sense probe to confirm a
flame is present. If a flame is not verified within predetermined
time period, the gas valve will immediately be closed, and
the blower will continue to run for approximately 30 seconds
interpurge. The control will try for ignition two more times
before lockout.
The row of status icons describe graphically operational details
of the heater. Following is a legend of all the status icons:
9. If a flame is confirmed, the control will enter the heating mode
where it will continue heating the tank water until the setpoint
temperature plus differential is reached. At this point, the gas
valve is closed and the control enters the post-purge cycle.
10. The combustion blower will run for the duration of the post purge
cycle to purge the system of all combustion gases. When the
post purge cycle is complete, the blower is de-energized and
will coast to a stop.
11. The control will now enter the idle state while continuing to
monitor the internal tank water temperature and the state of other
system devices. If the temperature drops below the setpoint
value less differential, the control will automatically return to
step 2 and repeat the entire operating cycle.
ELECTRONIC CONTROL
1. Overview
Interaction with the water heater controller is done through an up,
a down and three operation buttons. These buttons are shown
in the following illustration. Operation of the three lower buttons
is defined immediately above them on the screen. The UP and
DN buttons are used to navigate through the menus and make
adjustments to the water heater.
2. Operating States
In the main desktop screen, there are some specific Operating
States that are indicated on the status line. These are summerized
in the following table:
While the water heater is operating, the user interface will display
the desktop screen (if there are no active faults or warnings). An
example of this screen is shown in the following illustration. The
first temperature on this screen is the temperature of the water
20
3. Adjusting the Operating Set Point
The Operating Set Point of this water heater determines the regulated temperature for the water in the tank. This parameter is adjusted
in the Temperature menu. Items in this menu allow you to monitor different temperature readings in the tank along with adjusting the
Operating Set Point and Differential.
21
4. Changing the Display Units
The display interface to the heater has the option of selecting between degrees and Fahrenheit and degrees Celsius for temperature
displays. This can be found in the "Display Settings" menu. Also in this menu, you may adjust how the backlight operates and the
contrast of the LCD screen.
5. Fault and Warning Conditions
This water heater is equipped with electronic controls that have the ability to monitor almost all aspects of the water heater operation. In
the case that there is an undesirable or unsafe condition that occurs, the water heater controls will detect this condition and determine
the appropriate action. Part of this is displaying the information on the LCD in plain text that accurately describes the condition and
diagnostics information that can be used to correct the issue.
There are two types of conditions that can occur during operation. These are: Warnings and Faults:
• Warnings: This is a non-safety related condition that the control has detected that may cause the water heater to operate in a less
than optimal condition, but does not pose a safety concern.
NOTE: When these conditions occur, continued heating cycles will continue and the heater will attempt to regulate the water in the
tank to the Operating Set Point.
Example of a Warning:
22
• Faults: This is a safety related condition that has been detected by the heater.
NOTE: When these conditions occur, the water heater will not continue any further heating cycles and the water will no longer be
heated until the condition is corrected and, in most cases, power has been cycled.
Example of a Fault:
Advanced Diagnostics Information
When a fault or warning has been declared, advanced information can be found in the control. By pressing the Advanced button,
detailed information can be found regarding diagnosing and resolving the problem.
WARNING: Usage of the Advanced information requires ability equivalent to that of a license tradesmen in the
field involved.
6. Access to the Current Fault or Warning
When a fault or warning has been detected by the control, it will automatically be displayed on the screen and the back light will
blink. If you choose to leave the current fault or warning by pressing the Back key, you can always return to the fault screen through
the menu.
23
7. Viewing the Fault History
The controller for this water heater will store a history of ten of the last Fault and Warning conditions that occurred. This is stored in the
Fault History. Along with all the information about the fault, including a estimate time of when the fault occurred, information regarding
the advanced diagnostics for that fault can be accessed at any time.
8. Viewing Information About the Heater
The electronic control for this water heater monitors many different aspects of the water to ensure safe and optimal operation. Much
of the information monitored is available to view in two areas of the control. The first is the "Heater Status" and; the second is "Heater
Information". These items can be selected through the main menu in the same fashion as described above. In these menus, detailed
information about the water heater and the current status of specific conditions can be found.
24
PRIOR TO START UP - REQUIRED ABILITY
INSTALLATION OR SERVICE OF THIS WATER HEATER REQUIRES
ABILITY EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN
THE FIELD INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS
SUPPLY AND ELECTRICAL WORK ARE REQUIRED.
Before attempting start-up, thoroughly study and familiarize yourself
with the exact sequence of operation and all other details on the
specific heater being used.
The power burner is equipped with an ignition system which
automatically sequences prepurge and ignition, senses and
ignites main burner flame and sequences burner operation.
Heater is equipped with an ignition control which locks out after
three unsuccessful ignition attempts. Familiarize yourself with the
sequence of operation of this unit prior to start-up.
Be certain that the water heater is full of water, that air is purged
from all lines, there are no leaks (gas and water), and all inlet water
lines are open.
The following test equipment should be on hand (all test
equipment must be acclimated to ambient temperature before
calibration and use.)
– Two U-tube manometers or calibration 0-10" W.C. (0-2.5Kpa) and
0-35" W.C. (0-8.7Kpa) pressure gauges.
• Attach a gas pressure gauge or manometer to the upstream side
of main gas cock and a gas pressure gauge or manometer to the
manifold pressure tap.
• You are now ready to begin the burner start-up procedure.
OPERATING INSTRUCTIONS
IMPORTANT
IT IS RECOMMENDED THAT A QUALIFIED SERVICE TECHNICIAN
PERFORM THE INITIAL FIRING OF THE HEATER. AT THIS TIME THE
USER SHOULD ASK THE TECHNICIAN ANY QUESTIONS IN REGARD
TO THE OPERATION AND MAINTENANCE OF THE UNIT.
CAUTION
DO NOT USE THIS HEATER IF ANY PART HAS BEEN UNDER
WATER. IMMEDIATELY CALL A QUALIFIED SERVICE TECHNICIAN
TO INSPECT THE HEATER AND TO REPLACE ANY PART OF THE
CONTROL SYSTEM AND ANY GAS CONTROL WHICH HAS BEEN
UNDER WATER.
LIGHT THE UNIT IN ACCORDANCE WITH THE OPERATING
INSTRUCTIONS LABEL ATTACHED TO THE HEATER.
THESE INSTRUCTIONS ARE REPEATED IN THE LIGHTING AND
OPERATING LABEL ILLUSTRATION IN THIS MANUAL.
ADJUSTMENT PROCEDURE - Initial Start-up
A minimum dynamic gas supply pressure of 5.2" W.C. (1.29 kPa)
for Natural Gas and 11" W.C. (2.74 kPa) for LP Gas is required
before making any adjustment to the gas control pressure regulator
Attempts to adjust the regulator during periods of low gas supply
pressure could result in overfiring of the heater when the gas supply
pressure returns to normal.
1. Check gas line pressure with a manometer, adjust the gas supply
line pressure per table 4.
2. Check manifold pressure (see Table 4) using a pressure gauge
(manometer) connected to the manifold pressure tap on the gas
control valve, (Figure 15).
If full rate adjustment is required, remove cover screw from top of
the gas control valve, (Figure 15).
Using a small screwdriver, turn adjusting screw clockwise
to
increase or counterclockwise
to decrease gas pressure to
obtain 4.0" W.C. (0.996 kPa) for Natural Gas and 10" W.C. (2.49
kPa) for LP gas.
3. Cycle the burner on and off several times to check its operation.
4. Check the operation of the limit and operating controls.
5. Check the vent system seams and joints and ensure that there
is no discharge of flue products into the room.
6. Check the input rate:
BEFORE PROCEEDING WITH THE OPERATION OF THE UNIT,
MAKE SURE HEATER AND SYSTEM ARE FILLED WITH WATER
AND ALL AIR IS EXPELLED FROM HEATER AND PIPING.
For appliance installation locations with elevations above 10,000
feet (3,048 m) refer to HIGH ALTITUDE INSTALLATIONS section
of this manual.
NEVER OPERATE THE HEATER WITHOUT FIRST BEING
CERTAIN IT IS FILLED WITH WATER AND A TEMPERATURE AND
A PRESSURE RELIEF VALVE IS INSTALLED IN THE RELIEF VALVE
OPENING OF THE HEATER. DO NOT ATTEMPT TO OPERATE
HEATER WITH COLD WATER INLET VALVE CLOSED.
a. Attach a pressure gauge (manometer) to the manifold pressure
tap (Figure 16) and refer to Table 4 for correct pressure.
b. Use this formula to “clock” the meter. Be sure other gas
consuming appliances are not operating during this interval.
FILLING:
1. Close the heater drain valve.
2. Open a nearby hot water faucet to permit the air in the system
to escape.
3. Fully open the cold water inlet pipe valve allowing the heater
and piping to be filled.
4. Close the hot water faucet as water starts to flow.
5. The heater is ready to be operated.
3600 X H = Btuh
T
THE MAIN MANUAL GAS SHUTOFF VALVE MUST HAVE BEEN CLOSED
FOR AT LEAST FIVE (5) MINUTES. THIS WAITING PERIOD IS AN
IMPORTANT SAFETY STEP. ITS PURPOSE IS TO PERMIT GAS THAT
MIGHT HAVE ACCUMULATED IN THE COMBUSTION CHAMBER TO
CLEAR. IF YOU DETECT GAS AT THE END OF THIS PERIOD, DO NOT
PROCEED WITH LIGHTING. RECOGNIZE THAT GAS ODOR, EVEN IF
IT SEEMS WEAK, MAY INDICATE THE PRESENCE OF ACCUMULATED
GAS SOMEPLACE IN THE AREA WITH A RISK OF FIRE OR EXPLOSION.
SEE THE FRONT PAGE FOR STEPS TO BE TAKEN.
3600 X 1050 = 300,000 Btuh (87.9 kW)
12.6
T = Time in seconds to burn 1 cubic foot of gas. (With a stopwatch
read the gas meter and measure the amount of time required for
the heater to consume 1 cubic foot of gas.)
H = Heating value of gas (in Btu’s per cubic foot of gas).
Btuh = Actual heater input rate, in Btuh.
EXAMPLE: (Using BTH-300 heater)
T = 12.6 seconds
H = 1050 Btu/ft.3
BTUH = ?
For high altitude installations, compare result to the derated input
required for the elevation at the installation location.
Should it be necessary to adjust the gas pressure to the burner,
to obtain the full input rate, the steps below should be followed:
25
c. Remove the pressure regulator cover screw (Figure 16) and
adjust the pressure by turning the adjusting screw with a small
screwdriver. In this example, with heater running on natural
gas, do not exceed 4.0" (0.996 kPa) Water Column.
Clockwise to increase gas pressure and input rate.
Counterclockwise to decrease gas pressure and input rate.
e. Repeat steps (c) and (d) until the specified input rate is
achieved.
f. Turn the manual gas valve to “OFF”. Replace the pressure
regulator cover screw. Remove the pressure gauge or
manometer from the manifold pressure tap. Replace the
set screw in the manifold pressure tap. If the gas pressure
regulator cannot be adjusted to give the full input rating with
sufficient gas pressure at the valve, check to ensure the
unit is equipped with the correct orifice.
d. “Clock” the meter as in step (b) above.
LIGHTING AND OPERATION INSTRUCTIONS
FOR YOUR SAFETY READ BEFORE OPERATING
WARNING
IF YOU DO NOT FOLLOW THESE INSTRUCTIONS EXACTLY A FIRE OR EXPLOSION
MAY RESULT CAUSING PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE.
A.
This appliance does not have a pilot. It is equipped with
an ignition device which automatically lights the burner.
Do not try to light the burner by hand.
B.
BEFORE OPERATING smell all around the appliance area
for gas. Be sure to smell next to the floor because some
gas is heavier than air and will settle on the floor.
•
C.
Use only your hand to push in or turn the gas control
knob. Never use tools. If the knob will not push in or
turn by hand, don’t try to repair it, call a qualified service
technician. Force or attempted repair may result in fire
or explosion.
D.
Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect
the appliance and to replace any part of the control system
and any gas control which has been under water.
“WHAT TO DO IF YOU SMELL GAS”
•
•
•
Do not try to light any appliance.
Do not touch any electric switch; do not use any telephone
in your building.
Immediately call your gas supplier from a neighbor’s
telephone. Follow the gas supplier’s instructions.
If you cannot reach your gas supplier, call the fire
department.
OPERATING INSTRUCTIONS
9. Set thermostat to desired setting.
1. STOP! Read the safety information above on this label.
10. If the appliance will not operate, follow the instructions
“To Turn Off Gas To Appliance” and call your service
technician or gas supplier.
2. Set thermostat to lowest setting.
3. Turn off all electric power to the appliance.
4. This appliance is equipped with an ignition device which
automatically lights the burner. Do not try to light the
burner by hand.
5. Push in gas control knob slightly and turn clockwise
to “OFF”.
6. Wait five (5) minutes to clear out any gas. If you then
smell gas, STOP! Follow “B” in the safety information
above on
this label. If you don’t smell gas, go on to
the next step.
7. Turn gas control knob counterclockwise
to “ON”.
8. Turn on all electric power to the appliance.
FOR YOUR SAFETY READ BEFORE OPERATING
1. Set the thermostat to lowest setting.
2. Turn off all electric power to appliance if service is to be performed.
3. Push in gas control knob slightly and turn clockwise
to “OFF”. Do not force.
26
HIGH ALTITUDE INSTALLATIONS
WARNING
UNDER NO CIRCUMSTANCES SHOULD THE INPUT EXCEED
THE RATE SHOWN ON THE HEATER RATING PLATE.
OVERFIRING COULD RESULT IN DAMAGE OR SOOTING OF
THE HEATER.
CATHODIC PROTECTION
CAUTION
HYDROGEN GAS CAN BE PRODUCED IN A HOT WATER
SYSTEM SERVED BY THIS HEATER THAT HAS NOT BEEN
USED FOR A LONG PERIOD OF TIME (GENERALLY TWO
WEEKS OR MORE). HYDROGEN GAS IS EXTREMELY
FLAMMABLE. To reduce the risk of injury under these conditions,
it is recommended that a hot water faucet be opened for several
minutes before using any electrical appliance connected to the
hot water system. If hydrogen is present, there will probably be an
unusual sound such as air escaping through the pipe as the water
begins to flow. There should be no smoking or open flame near the
faucet at the time it is open.
WARNING
BTH HEATERS ARE CERTIFIED FOR USE WITHOUT
MODIFICATION FOR ALTITUDES UP TO 10,000 FEET.
INSTALLATIONS ABOVE 10,000 FEET MAY REQUIRE
REPLACEMENT OF THE BURNER ORIFICE. CALL THE
TECHNICAL INFORMATION CENTER AT (800) 527-1953 FOR
REQUIREMENTS.
Some gas utility companies derate their gas for altitude, making it
unnecessary to install high altitude orifices. Call the local gas or
utility company to verify BTU content.
Due to the input rating reduction at high altitudes, the output rating
of the appliance is also reduced and should be compensated for in
the sizing of the equipment for applications.
MAINTENANCE
PRECAUTIONS
IF THE UNIT IS EXPOSED TO OR EXHIBITS THE FOLLOWING,
DO NOT OPERATE HEATER UNTIL ALL CORRECTIVE STEPS
HAVE BEEN MADE BY A QUALIFIED SERVICEMAN.
1. FLOODING TO OR ABOVE THE LEVEL OF THE BURNER OR
CONTROLS
2. EXTERNAL DAMAGE
3. FIRING WITHOUT WATER
4. SOOTING
NEVER OPERATE THE HEATER WITHOUT FIRST BEING
CERTAIN IT IS FILLED WITH WATER AND A TEMPERATURE
AND PRESSURE RELIEF VALVE IS INSTALLED IN THE RELIEF
VALVE OPENING OF THE HEATER.
SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO
SHUT OFF, TURN OFF THE MANUAL GAS CONTROL VALVE TO
THE APPLIANCE.
GENERAL INFORMATION
The initial start-up procedure of the unit is provided on page 25.
The sequence of operation of the unit is provided on page 20.
It is important to note that the controller has a reset button on the
control box, Figure 1. The reset button is a safety device and would
not normally be used.
HIGH LIMIT
The high limit (not adjustable) is factory set to cutout at
202°F (94°C). The controller will not be reset until water temperature
drops to below 140°F (61°C).
Max. Gas Supply Pressure W.C.
Max. Gas Supply Pressure kPa
Nominal Gas Supply Pressure W.C.
Nominal Gas Supply Pressure kPa
Minimum Gas Supply Pressure W.C.*
Minimum Gas Supply Pressure kPa*
Manifold Gas Supply Pressure W.C.
Manifold Gas Supply Pressure kPa
Nat. Gas LP Gas
11.00
2.74
7.00
1.74
5.20
1.54
4.00 1.25
* Minimum pressure for purposes of rate adjustment
KEEP APPLIANCE AREA CLEAR AND FREE FROM
COMBUSTIBLE MATERIALS, GASOLINE AND OTHER
FLAMMABLE VAPORS AND LIQUIDS. (SEE WARNING ON PAGE
6, LOCATING THE HEATER).
Water heater maintenance includes periodic tank flushing
and cleaning, and removal of lime scale. The unit should be
inspected and adjusted to maintain proper combustion. Refer to
the following table. A periodic inspection of the venting system
should be made. Where used, the water circulating pump should
be oiled.
MAINTENANCE SCHEDULE
Following are the instructions for performing some of the
recommended maintenance. Unit inspection and adjustment should
be performed by a competent technician.
POWER BURNER
TABLE 4.
GAS SUPPLY SPECIFICATIONS
GENERAL
14.00
3.49
11.00
2.74
11.0
2.74
10.0
2.49
COMPONENT
Tank
Tank
OPERATION
INTERVAL
Sediment
Monthly
Flushing
Removal
Lime Scale
Removal
Semi Annually
Powered Anode
Inspect
System
Semi
Annually
Relief Valve
Inspect
Semi
Annually
Blower
REQUIRED
Clean Inlet
Screen and
Blower Wheel
Vent System
Inspect
UN-LIME®
Delimer
As Required
Soft Brush
Every 3
Months
Joints should
be sealed
(1) If furnished with oiling provision.
NOTE: UN•LIME is not available in Canada. Please call Customer
Service at 1-800-265-8520 for approved alternatives.
27
FLUSHING
Sediment and lime scale removal may be accomplished through
the cleanout opening furnished on the heater, see Figure 24. The
heater must be drained, see DRAINING, before removing cleanout
cover on tank.
1. Turn off the heater electrical disconnect switch.
2. Open the drain valve and allow water to flow until it runs clean.
3. Close the drain valve when finished flushing.
4. Turn on the heater electrical disconnect switch.
DRAINING
The heater must be drained if it is to be shut down and exposed to
freezing temperatures. Maintenance and service procedures may
also require draining the heater.
1. Turn off the heater electrical disconnect switch.
2. Close the cold water inlet valve to heater.
3. Open a nearby hot water faucet to vent the system.
4. Open the heater drain valve.
5. If the heater is being drained for an extended shutdown, it is
suggested the drain valve be left open during this period.
FIGURE 24.
To dissolve and remove the more stubborn mineral deposits,
A.O. Smith UN•LIME® Professional Delimer should be used. NOTE:
UN•LIME is not available in Canada. Please call Customer Service
at 1-800-265-8520 for approved alternatives.
• Follow FILLING instructions when restoring hot water service.
SEDIMENT REMOVAL
Waterborne impurities consist of the particles of soil and sand which
settle out and form a layer of sediment on the bottom of the tank.
A.O. Smith UN•LIME® Professional Delimer is an easy to handle
patented food grade acid formulated specifically for lime scale
removal from all types of water using equipment. Available in 1
gallon (3.8L) (part no. 4763) and 5 gallon (19L) (part no. 4813)
sizes. Hydrochloric base acids are not recommended for use on
glass-lined tanks.
A.O. Smith Form No. 4800 Rev. 8, entitled “Why, When and How”,
describes tank cleaning methods and materials. UN•LIME and
the booklet may be obtained through your A.O. Smith dealer or
distributor.
For convenience, sediment removal and lime scale removal should
be performed at the same time.
LIME SCALE REMOVAL
The amount of calcium carbonate (lime) released from water is
in direct proportion to water temperature and usage. The higher
the water temperature or water usage, the more lime deposits are
dropped out of the water. This is the lime scale which forms in pipes,
heaters and on cooking utensils.
The cleanout opening is shown in Figure 24. To clean heater through
cleanout opening, proceed as follow:
Lime accumulation not only reduces the life of the equipment but also
reduces efficiency of the heater and increases fuel consumption.
1. Turn off water inlet valve, the heater electrical disconnect switch
and open drain valve.
The usage of water softening equipment greatly reduces the
hardness of the water. However, this equipment does not always
remove all of the hardness (lime). For this reason it is recommended
that a regular schedule for deliming be maintained.
2. Remove outer cover plate from lower side of heater jacket.
3. Remove cover from cleanout opening.
4. Remove lime, scale or sediment using care not to damage the
glass-lining.
The depth of lime buildup should be measured periodically. Heaters
will have about 3" (7.6cm) of lime buildup when the level of lime has
reached the bottom of the cleanout opening or about 1" (2.5cm) of
lime buildup if it has reached the drain valve opening. A schedule
for deliming should be set up, based on the amount of time it would
take for a 1" (2.5cm) buildup of lime.
5. Inspect cleanout plate gasket: If new gasket is required, replace
with A. O. Smith part no. 99038.
6. Install cleanout plate. Be sure to draw plate up tight by tightening
screws securely.
Example 1:
Initial inspection shows 1/2" (1.3cm) of lime accumulation.
Therefore, the heater can be delimed once a year.
7. Close drain valve, open water inlet line and turn on the power
burner electrical disconnect switch.
8. Check for water leakage.
Example 2 :
Initial inspection shows 2" (5cm) of lime accumulation. Therefore,
the heater should be delimed every 3 months.
9. Replace outer jacket cover plate.
28
POWERED ANODE SYSTEM
To insure a long, trouble-free operating life, BTH 300, 400 and 500
are factory equipped with a powered anode system. The anodes
are of a permanent design and do not need replacing unless
damaged.
If the temperature and pressure relief valve on the heater discharges
periodically or continuously, it may be due to thermal expansion of
water in a closed water supply system, or, it may be due to a faulty
relief valve.
The heaters are equipped with a 3/4" drain valve.
Thermal expansion is the normal response of water when it is heated.
In a closed system, thermal expansion will cause the system pressure
to build until the relief valve actuation pressure is equaled. Then,
the relief valve will open, allowing some water to escape, slightly
lowering the pressure.
An access panel covers the cleanout opening in the tank which is
sealed by a gasket and cover, see Figure 24.
Contact your water supplier or local plumbing inspector on how to
control this situation.
RELIEF VALVE
Two common corrections are listed in the Checklist and Service
Information which appears later in this manual.
At least twice a year, the temperature and pressure relief valve should
be checked to ensure that it is in operating condition. To check the
relief valve, lift the lever at the end of the valve several times. The
valve should seat properly and operate freely.
ABOVE ALL, DO NOT PLUG THE TEMPERATURE AND PRESSURE
RELIEF VALVE. THIS IS NOT A SOLUTION AND CAN CREATE A
HAZARDOUS SITUATION.
DRAIN VALVE AND ACCESS PANELS
If water does not flow, remove and inspect for obstructions or
corrosion. Replace with a new valve of the recommended size as
necessary. Inspection of the valve should be performed at least every
three years. Do not attempt to repair the valve, as this could result
in improper operation and a tank explosion. In areas with poor water
conditions, it may be necessary to inspect the T&P valve more often
than every three years.
CAUTION
BEFORE MANUALLY OPERATING THE VALVE, MAKE SURE
THAT A DRAIN LINE HAS BEEN ATTACHED TO THE VALVE
TO DIRECT THE DISCHARGE TO AN OPEN DRAIN. FAILURE
TO TAKE THIS PRECAUTION COULD MEAN CONTACT WITH
EXTREMELY HOT WATER PASSING OUT THE VALVE DURING
THIS CHECKING OPERATION.
VENT SYSTEM
Examine the vent system every 3 months. Points of inspection are
as follows:
1. Check for obstructions and/or deterioration of vent piping and
vent hood. Replace immediately where needed.
2. Vent pipe and vent hood screen should be cleaned of foreign
material and soot. The screen is located inside the vent hood
outlet and is accessible from the outside of the hood. Do not
reach inside the vent hood when the heater is in operation.
3. Check all vent system connections for leakage and reseal as
required using Hi Temp Silicone sealer or equivalent.
29
INSTALLATION DIAGRAMS
ONE TEMPERATURE - ONE HEATER VERTICAL STORAGE TANK FORCED CIRCULATION
WITH OR WITHOUT BUILDING RECIRCULATION
CAUTION: IF BUILDING
COLD WATER SUPPLY HAS
A BACK-FLOW PREVENTER,
CHECK VALVE OR WATER
METER WITH CHECK VALVE
PROVISIONS FOR THERMAL
EXPANSION OF WATER IN THE
HOT WATER SYSTEM MUST
BE PROVIDED
NOTE: CONNECT RETURN
L I N E F R O M H O T WAT E R
CIRCULATING LOOP (IF USED)
TO COLD WATER INLET LINE.
* PIPE TO OPEN DRAIN
INSTALL IN ACCORDANCE
WITH LOCAL CODES
ONE TEMPERATURE - ONE HEATER HORIZONTAL STORAGE TANK
FORCED CIRCULATION WITH OR WITHOUT BUILDING RECIRCULATION
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED
SAFE TEMPERATURE AT FIXTURES. SEE WATER
TEMPERATURE CONTROL WARNING ON PAGE
3. IF HIGHER PREHEAT TEMPERATURES ARE
NECESSARY TO OBTAIN ADEQUATE BOOSTER
OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
*PIPE TO OPEN DRAIN
INSTALL IN ACCORDANCE
WITH LOCAL CODES
30
TWO TEMPERATURE - ONE HEATER HIGH TEMPERATURE
WITH OR WITHOUT BUILDING RECIRCULATION
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED
SAFE TEMPERATURE AT FIXTURES. SEE WATER
TEMPERATURE CONTROL WARNING ON PAGE 3. IF
HIGHER PREHEAT TEMPERATURES ARE NECESSARY
TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN
ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO
FIXTURES.
*PIPE RELIEF VALVE TO OPEN DRAIN.
N O T E : I F T E M P E R E D W AT E R I S
RECIRCULATED, RETURN LINE SHOULD
BE CONNECTED AT POINT “A”.
INSTALL IN ACCORDANCE WITH LOCAL
CODES.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A
BACK-FLOW PREVENTER, CHECK VALVE OR WATER
METER WITH CHECK VALVE PROVISIONS FOR
THERMAL EXPANSION OF WATER IN THE HOT WATER
SYSTEM MUST BE PROVIDED.
31
TWO TEMPERATURE - TWO HEATERS HIGH TEMPERATURE
WITH OR WITHOUT BUILDING RECIRCULATION
TWO TEMPERATURE - THREE HEATERS (TWO PRE-HEATERS/ONE BOOSTER HEATER)
WITH OR WITHOUT BUILDING RECIRCULATION
MUST BE IDENTICAL HEATERS
FOR MULTIPLE HEATER INSTALLATION SEE MANIFOLD KIT
SPECIFICATIONS, PAGE 35.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACKFLOW PREVENTER, CHECK VALVE OR WATER METER WITH
CHECK VALVE PROVISIONS FOR THERMAL EXPANSION OF
WATER IN THE HOT WATER SYSTEM MUST BE PROVIDED.
32
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 3. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
TWO TEMPERATURE - TWO HEATERS (ONE PRE-HEATER/ONE BOOSTER HEATER)
WITH OR WITHOUT BUILDING RECIRCULATION
* PIPE RELIEF VALVE TO OPEN DRAIN
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE TEMPERATURE
AT FIXTURES. SEE WATER TEMPERATURE CONTROL WARNING ON
PAGE 3. IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO
OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE
FOR HOT WATER SUPPLIED TO FIXTURES
**140°F (60°C)TO 150°F (66°C) SHOULD BE MAXIMUM WATER
TEMPERATURE MAINTAINED IN THE PRE-HEATERS.
120°F (49°C) SHOULD BE THE MINIMUM TEMPERATURE OF
WATER IN THE PRE-HEATERS.
CONNECT CIRCULATING LINE FROM FIXTURES, IF USED,
TO COLD WATER SUPPLY LINE OF PRE-HEATER.
CONNECT CIRCULATING LINE OF 180°F (82°C) OR BOOSTED
WATER, IF USED, TO INLET WATER LINE TO BOOSTER.
INSTALL IN ACCORDANCE WITH LOCAL CODES.
33
TWO TEMPERATURE - ONE HEATER HIGH TEMPERATURE
WITH RECIRCULATION OF SANITIZING LOOP
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 3. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACKFLOW PREVENTER, CHECK VALVE OR WATER METER WITH
CHECK VALVE PROVISIONS FOR THERMAL EXPANSION OF
WATER IN THE HOT WATER SYSTEM MUST BE PROVIDED.
*PIPE RELIEF VALVE TO OPEN DRAIN
NOTE 1: TOGGLE SWITCH CONTROLS 180°F (82°C) WATER
CIRCULATION. INSTALL ON OR CLOSE TO DISHWASHER.
TOGGLE SWITCH MUST BE CLOSED (ON) DURING THE RINSE
OPERATION AND OPEN (OFF) WHEN DISHWASHER IS NOT
OPERATING OR WHEN ON LONG STANDBY.
NOTE 2: INSTALL LINE TEMPERATURE CONTROL IN AN
UNINSULATED TEE BEYOND THE DISHWASHER TAKEOFF
IN THE SANITIZING LOOP. CONTROL SHOULD BE SET AT
185°F (85°C).
NOTE 3: ADJUST PLUG COCK SO THE SANITIZING LOOP
FLOW RATE DOES NOT CAUSE UNNECESSARY TURBULENCE
IN THE TANK.
NOTE 4: IF TEMPERED WATER IS RECIRCULATED, RETURN
LINE SHOULD BE CONNECTED AT POINT A.
INSTALL IN ACCORDANCE WITH LOCAL CODES
34
MULTIPLE UNIT INSTALLATIONS
Proper installation of multiple water heaters assures water flow balance of all units. Without this balance, the full water heating and storage
potential of the system cannot be achieved. Plus, the units with the higher water flow may have a shortened life.
Dimensions shown are for minimum space occupied by the water heaters assemblies.
Space for the venting system and unit servicing must be added.
Manifold Kits for multiple unit installations are not available from the manufacturer.
35
CHECKLIST AND SERVICE INFORMATION
10.Condensate hose may be blocked where it connects to the
exhaust elbow.
IMPORTANT
The installer may be able to observe and correct certain problems
which might arise when the unit is put into operation or when it is
re-fired after a prolonged shutdown. HOWEVER, it is recommended
that only qualified servicemen, using appropriate test equipment, be
allowed to service the heater.
• Verify the condensate drains from the unit without restriction.
WATER IS TOO HOT
1. Refer to WATER TEMPERATURE CONTROL.
WATER HEATER MAKES SOUNDS
BE SURE TO TURN OFF THE ELECTRICITY WHENEVER
POSSIBLE OR APPROPRIATE WHILE CHECKING EQUIPMENT.
1. Sediment or lime scale accumulations cause rumbling and
pounding noises when the heater is operating.
WARNING
FAILURE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN
SERIOUS PERSONAL INJURY OR DEATH.
CAUTION:
LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN
SERVICING CONTROLS. WIRING ERRORS CAN CAUSE
IMPROPER AND DANGEROUS OPERATION.
• The sounds are normal, however, the tank bottom should be
cleaned. Refer to MAINTENANCE for details.
2. Some of the electrical components of the water heater make
sounds which are normal.
VERIFY PROPER OPERATION AFTER SERVICING.
BURNER OPERATIONAL PROBLEMS
• Contacts click or snap as the heater starts and stops.
• Transformers often hum.
WATER LEAKAGE IS SUSPECTED
1. Refer to TROUBLESHOOTING.
1. Check to see if the water heater drain valve is tightly closed.
Also check the cleanout opening for leakage.
NOT ENOUGH OR NO HOT WATER
1. Be certain the electrical disconnect switch serving the water
heater is in the ON position.
2. The apparent leakage may be condensation which forms on cool
surfaces of the heater and piping.
2. Check the fuses.
3. If the outlet of the relief valve is leaking it may represent:
• The electrical disconnect switch usually contains fuses.
• Excessive water pressure.
3. The capacity of the heater may have been exceeded by a large
demand for hot water.
• Excessive water temperature.
• Faulty relief valve.
• Large demands require a recovery period to restore water temperature.
Excessive water pressure is the most common cause of relief valve
leakage. It is often caused by a “closed system”. If a check valve is
in the inlet system it will not permit the expanded hot water volume
to equalize pressure with the main. The relief valve must release this
water or the water heater or plumbing system will be damaged. Refer
to MAINTENANCE-RELIEF VALVE section in this manual.
4. Colder incoming water temperature will lengthen the time
required to heat water to the desired temperature.
• If the heater was installed when incoming water
temperature was warm, colder water creates the effect
of less hot water.
When such a condition is encountered, local codes or inspection
agency should be consulted to determine which system is acceptable
in your area. See CLOSED SYSTEM section in this manual.
5. Look for hot water wastage and leaking or open hot water
faucets.
TROUBLESHOOTING
6. Sediment or lime scale may be affecting water heater operation.
Refer to MAINTENANCE for details.
1. Verify that the allowable vent length has not been exceeded and
that the blower inlet screen has been removed if direct venting.
7. The heater’s temperature high limit sensor has activated. Press
the reset button on the thermostat.
2. Verify the gas supply volume and pressure per table 3 and 4.
8. Burner may not be firing at proper rate.
3. Verify that the condensation, which WILL be present in the heater
and exhaust vent, will drain.
• Check gas pressure. Adjust to obtain required manifold
pressure.
9. Burner fan wheel may be dirty.
4. Check supply wire polarity - hot to hot and neutral to neutral and
no "stray" current in neutral.
5. Heater is properly grounded.
• Clean fan wheel with a stiff brush.
36
this tubing is damaged it must be replaced. If these steps do not
eliminate the problem, replace the pressure switches.
Checking these four (4) items first will often result in a timely solution
to the service call.
WARNING
JUMPING OUT COMPONENTS AND/OR CIRCUITS DURING
TROUBLESHOOTING CAN CAUSE SERIOUS PROBLEMS WITH
THE UNIT’S OPERATING SEQUENCE AND IGNITION SAFETY.
IF YOU DO NOT HAVE THE PROPER TEST EQUIPMENT, I.E. A
VOLT-OHM METER AND A MICROMETER, DO NOT ATTEMPT TO
TROUBLESHOOT OR REPAIR A.O. SMITH EQUIPMENT.
5. Check to see if there is resistance across the igniter terminal
with an OHM meter. If there is no continuity, the igniter is
broken and should be replaced.
If the igniter appears to function properly, then verify that the
inlet pressure is 11.0" Natural Gas (2.74 kPa). The gas valve
supplied on this appliance is not designed to open against a
higher pressure. At this time also check that the inlet pressure
is not lower than the minimal gas supply pressure, as shown
in Table 4: that is, for Natural Gas, 5.2" (1.29 kPa) W.C. If
the inlet pressure is not within these limits then adjust the
supply pressure accordingly.
If the inlet pressure falls within the allowable limits, then verify
that the manifold pressure, when the gas is fully open, with
the heater running, is as called out in Table 4: that is, for
Natural Gas, 4.0" (0.996 kPa) W.C. If the manifold pressure
is not correct then adjust accordingly. See ADJUSTMENT
PROCEDURE in OPERATING INSTRUCTIONS for the
manifold pressure adjustment procedure.
ALTERING THE CONTROLLER AND/OR CONTROLLER WIRING
IN ANY WAY COULD RESULT IN INTERNAL DAMAGE TO THE
MODULE CIRCUITS, POSSIBLY ALTERING THE IGNITION
SEQUENCE ALLOWING GAS VALVES TO OPEN BEFORE THE
HOT SURFACE IGNITER IS UP TO IGNITION TEMPERATURE.
NOTE: ANY BYPASS OR ALTERATION OF THE UNITS SAFETIES
WILL RESULT IN VOIDING THE APPLIANCE WARRANTY.
Before performing any troubleshooting familiarize yourself with the
particular appliance.
Refer to the SEQUENCE OF OPERATION and the connection
diagram before continuing.
Make sure the appliance is connected to a 120V AC power supply,
manual gas valve is in the ON position, and all electrical connections
are secure before continuing to troubleshoot this appliance.
CAUTION
THE WATER HEATER IS POLARITY SENSITIVE. BEFORE APPLYING
ELECTRICITY TO THIS HEATER BE CERTAIN THAT SUPPLY NEUTRAL
WIRE TO GROUND CHECK INDICATES ZERO VOLTAGE.
6. If the inlet and manifold pressures are within the limits
specified in step 5, then reset the appliance. Verify 24V AC
at the gas valve during the three (3) second ignition trial, after
the igniter reaches operating temperature. If 24V AC at the
gas valve is not seen during this period, the controller must
be replaced.
MOTOR WILL NOT RUN
1. Confirm 120V AC. Also, to verify correct polarity, check for 120 V
AC between hot supply and ground. If there is no voltage, check
for a loose connection.
2. For BTH 400 and 500 a VFD (Variable Frequency Drive) is
used. "rdy" (stands for ready) will be shown on display in
standby heating mode. "155" (155 output Hz) shall be shown
on VFD display during heater running for BTH 400. "196" will be
displayed on VFD during BTH 500 running. Any other display
on the VFD indicates a faulty VFD or wrong speed reference,
call A.O. Smith Tech Center for assistance.
MOTOR RUNS, PREPURGE TIME ELAPSES BUT
MAIN FLAME NOT ESTABLISHED
1. Check to see if main manual gas valve is open.
2. Check for a loose connection at the transformer, or a defective
transformer.
3. Check for a loose connection at the gas valve.
4. Check for open pressure switches or open reset button. Check for
blockage in the intake and exhaust venting or at the vent hoods.
If no blockage is found, check vinyl tubing for cuts or crimps. If
If there is 24V AC at the gas valve during the four second
ignition trial and the manifold pressure does not increase
above 0" W.C. then verify that the manual gas control valve
is in the “ON” position. If the valve is in the “ON” position and
the previous voltage and gas pressure conditions are met,
then the gas valve is defective and must be replaced.
MOTOR RUNS, BURNER LIGHTS MOMENTARILY,
THEN LOCKS OUT
1. Reset the appliance two more times to ensure that all of the
air has been purged from the gas line.
2. If the burner lights momentarily but does not sustain
ignition, verify that the inlet pressure is not greater than
11.0" (2.74 kPa) W.C. or lower than the minimal gas
supply pressure, as shown in Table 4: that is, for Natural
Gas, 5.2" (1.29 kPa) W.C. pressure. Also, the manifold
pressure should rise during the three (3) second trial for
ignition to the manifold pressure value for the individual
unit listed in Table 4: that is, for Natural Gas, 4.0" (0.996
kPa) W.C. If the manifold pressure is not correct then
adjust accordingly. See ADJUSTMENT PROCEDURE in
OPERATING INSTRUCTIONS section for the manifold
pressure adjustment procedure.
3. Check for the reversed polarity in the supply wiring. This
controller is polarity sensitive. If the hot and neutral supply
wires are reversed, the controller will not sense flame. Reverse
the supply wires and try to fire the unit.
37
NOISY BURNER OPERATION
NOTE: Always turn off and disconnect main supply wiring before
servicing the unit.
The exhaust of this unit produces some noise during ignition period.
When combustion is too lean or too rich, start up noise will get worse.
Check for flue gas CO2 reading, adjust gas valve manifold pressure
if required to bring the flue gas CO2 to 9–9.5% level for natural gas,
10.75–11.25% for LP. This noise may be objectionable if the exhaust
terminal is located too close to the opening of an occupied space.
The noise may also be objectionable if the exhaust is located in the
confined space between two buildings such as an alley or walkway.
Since everyone's perception and tolerance for background noise
varies, there is no standard recommendation. The best option
when the noise is a concern is to fine-tune the air/gas ratio of the
combustion system or locate the exhaust as far away from any
occupied spaces as practical.
4. Check connecting wire to the flame sensor. Verify that the flame
sensor has not been damaged in any way.
5. Verify that the air supply is adequate. The air inlet screen or blower
wheel may be restricted. Also, check the installation for proper
ventilation. See AIR REQUIREMENTS.
6. Check the venting system for the correct sizing, excess or
insufficient. See VENTING.
7. Check for a maximum inlet pressure of 11" Natural Gas
(2.74 kPa) W.C. and the manifold pressure as listed in Table 4:
that is, for Natural Gas, 4.0" (0.996 kPa) W.C. Please note that
the manifold pressure listed is the maximum value for the manifold
pressure. Do not set the manifold pressure higher than the value
shown for your heater in Table 4. Overfiring the heater will result
in rough ignition and/or noisy operation.
GAS FAILS TO SHUT OFF
Check for defective gas valve or thermostat. If operation is
incorrect, replace.
REPLACEMENT PARTS
8. Confirm that the air inlet screen (see Figures 7 & 8) is free of
obstructions.
Replacement parts may be ordered through A.O. Smith dealers,
authorized servicers or distributors. Refer to the Yellow Pages for
where to call or contact the A.O. Smith Water Products Company,
125 Southeast Parkway, Franklin, TN 37068, 1-800-433-2545.
When ordering parts be sure to state the quantity, part number
and description of the items including the complete model and
serial number as it appears on the product. Refer to the parts list
for more information.
CAUTION
Do not reach into the burner housing or combustion chamber if the
heater is still hot. Allow the heater to cool and always use gloves as
the combustion chamber and the burner sleeve and housing can
become very hot after operation. Overfiring is a dangerous condition
that must be corrected immediately.
38
Model BTH Limited Warranty
A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this water heater.
1. THE TANK
If the glass-lined tank in this water heater shall prove upon examination by the warrantor to have leaked due to natural corrosion from potable water
therein, during the first THREE years after initial installation, the warrantor will supply a replacement tank less burner and controls or a complete new
A.O. Smith water heater of equivalent size and current model at the warrantor's option. Some government agencies are requiring energy efficient
standards for water heaters. In the event regulations prohibit sale of a model of equivalent size and construction, A.O. Smith will provide a model which
complies with the regulations of your area, in which case the consumer will be charged the difference in price between the like replacement and the
energy efficient model required. The warranty on the replacement water heater will be limited to the unexpired term of the original warranty.
2. ALL OTHER PARTS
If within ONE year after initial installation of this water heater, any part or portion shall prove upon examination by the warrantor to be defective in material
or workmanship, the warrantor will repair or replace such part or portion at its option.
3. CONDITIONS AND EXCEPTIONS
This warranty shall apply only when the water heater is installed in accordance with local plumbing and building codes, ordinances and regulations, the
printed instructions provided with it and good industry practices. In addition, a temperature and pressure relief valve, certified by A.G.A. and approved
by the American Society of Mechanical Engineers, must have been installed.
a.This warranty shall apply only when the heater is:
(1) owned by the original purchaser;
(2) used at temperatures not exceeding the maximum setting of its thermostat;
(3) used at water pressure not exceeding the working pressure shown on the heater;
(4) used when operated free of the damaging effects of uncontrolled water hammer;
(5) used when filled with potable water, free to circulate at all times;
(6) used in a non-corrosive and non-contaminated atmosphere;
(7) used with factory approved anode(s) installed;
(8) in its original installation location;
(9) in the United States, its territories or possessions, and Canada;
(10) sized in accordance with proper sizing techniques for commercial water heaters;
(11) bearing a rating plate which has not been altered, defaced or removed except as required by the warrantor;
(12) fired at the factory rated input using the fuel stated on the rating plate;
(13) maintained in accordance with the instructions printed in the manual included with the heater.
b.Any accident to the water heater, any misuse, abuse (including freezing) or alteration of it, any operation of it in a modified form, or any attempt to
repair tank leaks will void this warranty.
c.This warranty is void if a device acting as a backflow prevention device (check valves etc.) is installed in the cold water supply the heater is connected
to, unless an effective method of controlling thermal expansion is also installed at the heater(s) and operational at all times.
The relief valve installed on the heater is not an acceptable method.
4. SERVICE AND REPAIR EXPENSES
Under the limited warranty the warrantor will provide only a replacement water heater or part thereof. The owner is responsible for all other costs. Such
costs may include but are not limited to:
a. Labor charges for service removal, repair or reinstallation of the water heater or any component part;
b. Shipping, delivery, handling, and administrative charges for forwarding the new heater or replacement part from the nearest distributor and returning
the claimed defective heater or part to such distributor.
c. All cost necessary or incidental for any material and/or permits required for installation of the replacement.
5. LIMITATIONS ON IMPLIED WARRANTIES
Implied warranties, including the warranty of merchantability imposed on the sale of this heater under state law are limited to one (1) year duration for the
heater or any of its parts. Some states do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply to you.
6. CLAIM PROCEDURE
Any claim under the warranty should be initiated with the dealer who sold the water heater, or with any other dealer handling the warrantor’s
products. If this is not practicable, the owner should contact:
U.S. Customers
Canadian Customers
A. O. Smith Corporation
A. O. Smith Enterprises Ltd.
500 Tennessee Waltz Parkway
P. O. Box, 310 - 768 Erie Street
Ashland City, TN 37015
Stratford (Ontario) N5A 6T3
Telephone: 1-(800)-323-2636
Telephone: 1-(800) 265-8520
a. The warrantor will only honor replacement with identical or similar water heater or parts thereof which are manufactured or distributed by the warrantor.
b. Dealer replacements are made subject to in-warranty validation by warrantor.
7. DISCLAIMERS
NO OTHER EXPRESS WARRANTY HAS BEEN OR WILL BE MADE IN BEHALF OF THE WARRANTOR WITH RESPECT TO THE MERCHANTABILITY
OF THE HEATER OR THE INSTALLATION, OPERATION, REPAIR OR REPLACEMENT OF THE WATER HEATER. THE WARRANTOR SHALL NOT BE
RESPONSIBLE FOR WATER DAMAGE, LOSS OF USE OF THE UNIT, INCONVENIENCE, LOSS OR DAMAGE TO PERSONAL PROPERTY OR OTHER
CONSEQUENTIAL DAMAGE. THE WARRANTOR SHALL NOT BE LIABLE BY VIRTUE OF THIS WARRANTY OR OTHERWISE FOR DAMAGE TO ANY
PERSONS OR PROPERTY, WHETHER DIRECT OR INDIRECT, AND WHETHER ARISING IN CONTRACT OR TORT.
a. Some states do not allow the exclusion or limitation of the incidental or consequential damage, so the above limitations or exclusions may not apply to you.
b. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.
Fill in the following for your own reference. Keep it. Registration is not a condition of warranty. The model and serial number are found on the heater’s
rating plate.
Date Installed________________________Model No.____________________________________________Serial No._________________________________________
Dealer’s Name _____________________________________________________________________Phone No.________________________________________________
Dealer’s Address__________________________________________________City and State________________________________________Zip Code________________
FILL IN WARRANTY AND KEEP FOR FUTURE REFERENCE.
39
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