INSTALLATION INSTRUCTIONS
A80US2V
Warm Air Gas Furnace
Upflow / Horizontal Left and Right Air Discharge
This manual must be left with the homeowner for future reference.
This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in
manuals, be alert to the potential for personal injury or death.
CAUTION
NOTICE
As with any mechanical equipment, personal injury can
result from contact with sharp sheet metal edges. Be
careful when you handle this equipment.
A thermostat is not included and must be ordered
separately.
• A Comfort Sync™ thermostat must be used in
communicating applications.
• In non-communicating applications, a traditional noncommunication thermostat may be used.
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause property damage, personal injury
or loss of life. Installation and service must be performed
by a licensed professional installer (or equivalent), service
agency or the gas supplier.
In all cases, setup is critical to ensure proper system
operation.
Field wiring for both communicating and noncommunicating applications is illustrated in these
instructions.
TABLE OF CONTENTS
Electrical ..................................................................... 25
Thermostat .................................................................. 27
Unit Start-Up ............................................................... 30
High Altitude ................................................................ 32
Gas Pressure Adjustment ........................................... 33
Sequence of Operation ............................................... 33
Other Unit Adjustments ............................................... 33
Maintenance ............................................................... 36
Repair Parts List ......................................................... 40
Wiring Diagram ........................................................... 41
Wiring Schematic ........................................................ 42
Start Up & Performance Check List ............................ 43
Unit Dimensions ............................................................ 2
A80US2V Parts Arrangement ....................................... 3
A80US2V Gas Furnace ................................................ 4
Shipping and Packing List ............................................ 4
Safety Information ......................................................... 4
Use of Furnace as a Construction Heater .................... 5
General ......................................................................... 6
Combustion, Dilution, Ventilation Air ............................. 6
Setting Equipment ........................................................ 9
Filters .......................................................................... 12
Duct System ................................................................ 12
Venting ........................................................................ 13
Gas Piping .................................................................. 23
Manufactured By
Allied Air Enterprises LLC
A Lennox International, Inc. Company
215 Metropolitan Drive
West Columbia, SC 29170
*p506891-01*
(P) 506891-01
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Page 1 of 65
A80US2V Unit Dimensions - inches (mm)
1. NOTE - 20C and 20D size units installed in upflow applications
that require air volumes of 1800 cfm (850 L/s) or greater must
have one of the following:
1. Single side return air with transition to accommodate
20 x 25 x 1in. (508 x 635 x 25 mm) cleanable air filter.
(Required to maintain proper air velocity.)
2. Single side return air with optional RAB Return Air Base
3. Return Air from bottom and one side.
4. Return air from both sides.
5. Return air from bottom.
2. Flue outlet may be horizontal but furnace must be vented
vertically.
3. Optional external side return air filter kit cannot be used with
the optional RAB Return Air Base.
* Consider sizing requirements for optional IAQ equipment before
cutting side return opening.
SIDE VIEW
FRONT VIEW
Model
070-12
B
A
in.
mm
D
C
in.
mm
in.
mm
in.
mm
14-1/2
368
13-3/8
340
13
330
4-3/4
121
17-1/2
446
16-3/8
416
16
406
6-1/4
159
21
533
19-7/8
504
19-1/2
495
8
203
24-1/2
622
546
23
584
9-3/4
248
090-12
090-16
090-20
110-20
135-20
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23-3/8
Issue 1235
506891-01
EXPANDED VIEW
HEAT EXCHANGER
COMBUSTION AIR INDUCER
COMBUSTION AIR INDUCER
PRESSURE SWITCH
ROLLOUT SWITCH
GAS VALVE
CABINET
BURNER BOX
CONTROL BOX
(INCLUDES INTEGRATED CONTROL,
AND TRANSFORMER)
BURNER
ACCESS PANEL
BLOWER
ACCESS
PANEL
BLOWER ASSEMBLY
Figure 1
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A80US2V Gas Furnace
The A80US2V gas furnace is shipped ready for installation
in the upflow or horizontal position (left or right). The furnace
is shipped with the bottom panel in place. The bottom panel
must be removed if the unit is to be installed in a horizontal
application. The panel may also be removed in upflow
applications.
The furnace is equipped for installation in natural gas
applications. A conversion kit (ordered separately) is required
for use in propane/LP gas applications.
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
Please refer to specification sheets for available accessories.
DANGER
DANGER OF EXPLOSION!
There are circumstances in which odorant used with
LP/Propane gas can lose its scent. In case of a leak,
LP/Propane gas will settle close to the floor and may be
difficult to smell. An LP/Propane leak detector should
be installed in all LP applications.
WARNING
As with any mechanical equipment, personal injury can
result from contact with sharp sheet metal edges. Be
careful when you handle this equipment.
Certifications
These units are CSA International certified to ANSI Z21.47.
In the USA, installation of gas furnaces must conform with
local building codes. In the absence of local codes, units
must be installed according to the current National Fuel Gas
Code (ANSI-Z223.1). The National Fuel Gas Code is
available from the following address: American National
Standards Institute, Inc., 11 West 42nd Street, New York,
NY 10036.
Shipping and Packing List
1 - Assembled Gas Furnace
1 - Bag assembly containing the following:
2 - Screws
3 - Wire nuts
1 - Snap bushing
1 - Snap Plug
1 - Wire tie
1 - Vent warning label
1 - Owner’s manual and warranty card
Safety Information
CAUTION
Clearances
Adequate clearance must be made around the air openings
into the vestibule area. In order to ensure proper unit
operation, combustion and ventilation air supply must be
provided according to the current National Fuel Gas Code.
Vent installations must be consistent with the venting tables
(in this instruction) and applicable provisions of local building
codes.
This furnace is CSA International certified for installation
clearances to combustible material as listed on the unit
nameplate and in the tables in Figures 7 and 11. Accessibility
and service clearances must take precedence over fire
protection clearances.
NOTE: For installation on combustible floors, the furnace
shall not be installed directly on carpeting, tile, or other
combustible material other than wood flooring.
Installed Locations
For installation in a residential garage, the furnace must be
installed so that the burner(s) and the ignition source are
located no less than 18 inches (457 mm) above the floor.
The furnace must be located or protected to avoid physical
damage by vehicles. When a furnace is installed in a public
garage, hangar, or other building that has a hazardous
atmosphere, the furnace must be installed according to
recommended good practice requirements and current
National Fuel Gas Code.
Improper installation, adjustment, alteration, service or
maintenance can cause property damage, personal
injury or loss of life. Installation and service must be
performed by a licensed professional installer (or
equivalent), service agency or the gas supplier.
Page 4 of 65
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506891-01
Temperature Rise
NOTE: Furnace must be adjusted to obtain a temperature
rise (high and low fire) within the range(s) specified on the
unit nameplate. Failure to do so may cause erratic limit
operation and may result in premature heat exchanger
failure.
This furnace must be installed so that its electrical
components are protected from water.
Installed in Combination with a Cooling Coil
When this furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating compartment. See
Figure 2. With a parallel flow arrangement, a damper (or
other means to control the flow of air) must adequately
prevent chilled air from entering the furnace. If the damper
is manually operated, it must be equipped to prevent
operation of either the heating or the cooling unit, unless it
is in the full HEAT or COOL setting. See Figure 2.
This furnace may be installed in alcoves, closets, attics,
basements, garages, and utility rooms in the upflow or
horizontal position.
This furnace design has not been certified for
installation in mobile homes, recreational vehicles, or
outdoors.
Use of Furnace as a Construction Heater
Allied Air does not recommend the use of these units as a
construction heater during any phase of construction. Very
low return air temperature, harmful vapors and operation of
the unit with clogged or misplaced filters will damage the
unit.
Units may be used for heating of buildings or structures
under construction, if the following conditions are met:
• The vent system must be permanently installed per these
installation instructions.
•
A room thermostat must control the furnace. The use of
fixed jumpers that will provide continuous heating is not
allowed.
•
The return air duct must be provided and sealed to the
furnace.
•
Return air temperature range between 60°F (16°C) and
80°F (27°C) must be maintained.
•
Air filters must be installed in the system and must be
maintained during construction.
•
Air filters must be replaced upon construction
completion.
•
The input rate and temperature rise must be set per the
furnace rating plate.
•
One hundred percent (100%) outdoor air must be
provided for combustion air requirements during
construction. Temporary ducting may supply outdoor air
to the furnace. Do not connect duct directly to the
furnace. Size the temporary duct following these
instructions in section for Combustion, Dilution and
Ventilation Air in a confined space with air from outside.
•
The furnace heat exchanger, components, duct system,
air filters and evaporator coils must be thoroughly
cleaned following final construction clean-up.
•
All furnace operating conditions (including ignition, input
rate, temperature rise and venting) must be verified
according to these installation instructions.
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Heating Unit Installed Parallel to Air Handler Unit
Heating Unit Installed Upstream of Cooling Unit
Figure 2
When installed, this furnace must be electrically grounded
according to local codes. In addition, in the United States,
installation must conform with the current National Electric
Code, ANSI/NFPA No. 70. The National Electric Code (ANSI/
NFPA No. 70) is available from the following address:
National Fire Protection Association
1 Battery March Park
Quincy, MA 02269
NOTE: This furnace is designed for a minimum continuous
return air temperature of 60° F (16°C) or an intermittent
operation down to 55° F (13°C) dry bulb for cases where a
night setback thermostat is used. Return air temperature
must not exceed 85° F (29°C) dry bulb.
506891-01
General
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
In addition to the requirements outlined previously, the
following general recommendations must be considered
when installing one of these furnaces:
•
•
•
•
Place the furnace as close to the center of the air
distribution system as possible. The furnace should also
be located close to the chimney or vent termination point.
Do not install the furnace where drafts might blow directly
into it. This could cause improper combustion.
Do not block the furnace combustion air openings with
clothing, boxes, doors, etc. Air is needed for proper
combustion and safe unit operation.
When the furnace is installed in an attic or other insulated
space, keep insulation away from the furnace.
NOTE: The Commonwealth of Massachusetts stipulates
these additional requirements:
•
•
•
Gas furnaces shall be installed by a licensed plumber
or fitter only.
The gas cock must be “T handle” type.
When a furnace is installed in an attic, the passageway
to and service area surrounding the equipment shall be
floored.
Combustion, Dilution & Ventilation Air
In the past, there was no problem in bringing in sufficient
outdoor air for combustion. Infiltration provided all the air
that was needed. In today’s homes, tight construction
practices make it necessary to bring in air from outside for
combustion. Take into account that exhaust fans, appliance
vents, chimneys, and fireplaces force additional air that could
be used for combustion out of the house. Unless outside
air is brought into the house for combustion, negative
pressure (outside pressure is greater than inside pressure)
will build to the point that a downdraft can occur in the furnace
vent pipe or chimney. As a result, combustion gases enter
the living space creating a potentially dangerous situation.
In the absence of local codes concerning air for combustion
and ventilation, use the guidelines and procedures in this
section to install these furnaces to ensure efficient and safe
operation. You must consider combustion air needs and
requirements for exhaust vents and gas piping.
A portion of this information has been reprinted with
permission from the National Fuel Gas Code (ANSI-Z223.1).
This reprinted material is not the complete and official
position of the ANSI on the referenced subject, which is
represented only by the standard in its entirety.
Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rusting
and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result in
safety and performance related problems. Avoid
exposure to the following substances in the combustion
air supply:
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine base swimming pool chemicals
Water softening chemicals
De-icing salts or chemicals
Carbon tetrachloride
Halogen type refrigerants
Cleaning solvents (such as perchloroethylene)
Printing inks, paint removers, varnishes, etc.
Hydrochloric acid
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials
WARNING
The State of California has determined that this product
may contain or produce a chemical or chenmicals, in
very low doses, which may cause serious illness or
death. It may also cause cancer, bith defects or other
reproductive harm.
Page 6 of 65
WARNING
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506891-01
All gas fired appliances require air for the combustion
process. If sufficient combustion air is not available, the
furnace or other appliances will operate inefficiently and
unsafely. Enough air must be provided to meet the needs
of all fuel burning appliances and appliances such as exhaust
fans which force air out of the house. When fireplaces,
exhaust fans, or clothes dryers are used at the same time
as the furnace, much more air is necessary to ensure proper
combustion and to prevent a downdraft. Insufficient air
causes incomplete combustion which can result in carbon
monoxide.
Equipment in Confined Space - All Air From Inside
In addition to providing combustion air, fresh outdoor air
dilutes contaminants in the indoor air. These contaminants
may include bleaches, adhesives, detergents, solvents and
other contaminants which can corrode furnace components.
NOTE: Each opening shall have a free area of at least one square
inch per 1,000 Btu (645 mm² per .29 kW) per hour of the total input
rating of all equipment in the enclosure, but not less than 100 square
inches (64516 mm²).
The requirements for providing air for combustion and
ventilation depend largely on whether the furnace is installed
in an unconfined or a confined space.
Unconfined Space
An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the
combined input rating of all appliances installed in that space.
This space also includes adjacent rooms which are not
separated by a door. Though an area may appear to be
unconfined, it might be necessary to bring in outdoor air for
combustion if the structure does not provide enough air by
infiltration. If the furnace is located in a building of tight
construction with weather stripping and caulking around the
windows and doors, follow the procedures in the air from
outside section.
Confined Space
A confined space is an area with a volume less than 50
cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the
combined input rating of all appliances installed in that space.
This definition includes furnace closets or small equipment
rooms.
When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space
containing the furnace, the return air must be handled by
ducts which are sealed to the furnace casing and which
terminate outside the space containing the furnace. This is
especially important when the furnace is mounted on a
platform in a confined space such as a closet or small
equipment room. Even a small leak around the base of the
unit at the platform or at the return air duct connection can
cause a potentially dangerous negative pressure condition.
Air for combustion and ventilation can be brought into the
confined space either from inside the building or from outside.
506891-01
Figure 3
Air from Inside
If the confined space that houses the furnace adjoins a
space categorized as unconfined, air can be brought in by
providing two permanent openings between the two spaces.
Each opening must have a minimum free area of 1 square
inch (645 mm2) per 1,000 Btu (.29 kW) per hour of total
input rating of all gas fired equipment in the confined space.
Each opening must be at least 100 square inches (64516
mm2). One opening shall be within 12 inches (305 mm) of
the top of the enclosure and one opening within 12 inches
(305 mm) of the bottom. See Figure 3.
Air from Outside
If air from outside is brought in for combustion and ventilation,
the confined space must have two permanent openings. One
opening shall be within 12 inches (305 mm) of the top of the
enclosure and one opening within 12 inches (305 mm) of
the bottom. These openings must communicate directly or
by ducts with the outdoors or spaces (crawl or attic) that
freely communicate with the outdoors or indirectly through
vertical ducts. Each opening shall have a minimum free
area of 1 square inch (645 mm2) per 4,000 Btu (1.17 kW)
per hour of total input rating of all equipment in the enclosure.
See Figures 4 and 5. When communicating with the
outdoors through horizontal ducts, each opening shall have
a minimum free area of 1 square inch (645 mm2) per 2,000
Btu (.56 kW) per total input rating of all equipment in the
enclosure. See Figure 6.
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When ducts are used, they shall be of the same cross
sectional area as the free area of the openings to which
they connect. The minimum dimension of rectangular air
ducts shall be no less than 3 inches (75 mm). In calculating
free area, the blocking effect of louvers, grilles, or screens
must be considered. If the design and free area of protective
covering is not known for calculating the size opening
required, it may be assumed that wood louvers will have 20
to 25 percent free area and metal louvers and grilles will
have 60 to 75 percent free area. Louvers and grilles must
be fixed in the open position or interlocked with the
equipment so that they are opened automatically during
equipment operation.
EQUIPMENT IN CONFINED SPACE
(ALL AIR FROM OUTSIDE)
EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE
(Inlet Air from Crawlspace &
Outlet Air to Ventilated Attic)
NOTE: Each air duct opening shall have a free area of at least one
square inch per 2,000 Btu (645 mm² per .59 kW) per hour of the
total input rating of all equipment in the enclosure. If the equipment
room is located against an outside wall and the air openings
communicate directly with the outdoors, each opening shall have a
free area of at least 1 square inch per 4,000 Btu (645 mm² per 1.17
kW) per hour of the total input rating of all other equipment in the
enclosure.
Figure 6
NOTE: The inlet and outlet air openings shall each have a free area
of at least one square inch per 4,000 Btu (645 mm² per 1.17 kW) per
hour of the total input rating of all equipment in the enclosure.
Figure 4
EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE
(All Air through Ventilated Attic)
NOTE: The inlet and outlet air openings shall each have a free area
of at least one square inch per 4,000 Btu (645 mm² per 1.17 kW) per
hour of the total input rating of all equipment in the enclosure.
Figure 5
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506891-01
Setting Equipment
Upflow Applications
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or
alcove installations are shown in Figure 8.
WARNING
Do not install the furnace on its front or its back. Do not
connect the return air ducts to the back of the furnace.
Doing so will adversely affect the operation of the safety
control devices, which could result in personal injury or
death.
Upflow Application Installation Clearances
The gas furnace can be installed as shipped in either the
upflow position or the horizontal position.
Select a location that allows for the required clearances that
are listed on the unit nameplate. Also consider gas supply
connections, electrical supply, vent connection, and
installation and service clearances [24 inches (610 mm) at
unit front]. The unit must be level.
NOTE: Units with 1/2 hp blower motors are equipped with
three flexible legs and one rigid leg. See Figure 7. The rigid
leg is equipped with a shipping bolt and a flat white plastic
washer (rather than the rubber mounting grommet used with
a flexible mounting leg). The bolt and washer must be
removed before the furnace is placed into operation. After
the bolt and washer have been removed, the rigid leg will
not touch the blower housing.
Units with 1/2 HP
Blower Motor.
* Front clearance In alcove Installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
‡ For installation on a combustible floor, do not install the furnace
directly on carpeting, tile or other combustible materials other than
wood flooring.
† Left side requires 3 inches if a single wall vent is used on 14-1/2
inch cabinets.
Figure 8
Figure 7
506891-01
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Return Air - Upflow Applications
Return air can be brought in through the bottom or either
side of the furnace installed in an upflow application. If the
furnace is installed on a platform with bottom return, make
an airtight seal between the bottom of the furnace and the
platform to ensure that the furnace operates properly and
safely. The furnace is equipped with a removable bottom
panel to facilitate installation.
Single Side Return Air
(with transition and filter)
Markings are provided on both sides of the furnace cabinet
for installations that require side return air. Cut the furnace
cabinet at the maximum dimensions shown on page 2.
NOTE: 20C and 20D units that require air volumes over
1800 cfm (850 L/s) must have one of the following:
1. Single side return air with transition to
accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm)
cleanable air filter. (Required to maintain proper air
velocity.) See Figure 9.
2. Single side return air with optional return airbase.
See Figure 10.
3. Bottom return air.
4. Return air from both sides.
5. Bottom and one side return air.
Figure 9
Optional Return Air Base
(Upflow Applications Only - For use with A, B, C and D cabinets))
NOTE: Optional Side Return Air Filter Kits are not for use with Return Air Base.
1 Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.
Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in. (584 x 279 mm).
The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.
Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return air opening.
The size of the opening must not extend beyond the markings on the furnace cabinet.
² To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.
Figure 10
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506891-01
Removing the Bottom Panel
Remove the two screws that secure the bottom cap to the
furnace. Pivot the bottom cap down to release the bottom
panel. Once the bottom panel has been removed, reinstall
the bottom cap. See Figure 11.
Removing the Bottom Panel
Horizontal Applications
The furnace can be installed in horizontal applications. Order
horizontal suspension kit (51W10) from Allied Air, or use
equivalent suspension method.
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or
alcove installations are shown in Figure 12.
This furnace may be installed in either an attic or a crawl
space. Either suspend the furnace from roof rafters or floor
joists, as shown in Figure 13, or install the furnace on a
platform, as shown in Figure 14.
Typical Horizontal Application
Unit Suspended in Attic or Crawlspace
Figure 11
Horizontal Application
Installation clearances
Figure 13
NOTE: Heavy gauge perforated sheet metal straps may
be used to suspend the unit from roof rafters or ceiling joists.
When straps are used to suspend the unit in this way, support
must be provided for both the ends. The straps must not
interfere with the plenum or exhaust piping installation.
Cooling coils and supply and return air plenums must
be supported separately.
NOTE: When the furnace is installed on a platform in a
crawlspace, it must be elevated enough to avoid water
damage and to allow the evaporator coil to drain.
* Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 21 in. (610 mm) for front service access.
‡ For installations on a combustible floor, do not install the furnace
directly on carpeting, tile or other combustible materials other than
wood flooring.
Return Air - Horizontal Applications
Return air must be brought in through the end of a furnace
installed in a horizontal application. The furnace is equipped
with a removable bottom panel to facilitate installation. See
Figure 11.
Figure 12
506891-01
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Page 11 of 65
Horizontal Application
Unit installed on Platform
Table 1
Duct System
Use industry approved standards (such as those published
by Air Conditioning Contractors of America or American
Society of Heating, Refrigerating and Air Conditioning
Engineers) to size and install the supply and return air duct
system. This will result in a quiet and low static system that
has uniform air distribution.
Figure 14
NOTE: Do not operate the furnace in the heating mode
with an external static pressure that exceeds 0.8 inches w.c.
Higher external static pressures may cause erratic limit
operation.
WARNING
Improper installation of the furnace can result in personal
injury or death. Combustion and flue products must
never be allowed to enter the return air system or the
living space. Use screws and joint tape to seal the return
air system to the furnace.
Supply Air Plenum
If the furnace is installed without a cooling coil, a removable
access panel must be installed in the supply air duct. The
access panel should be large enough to permit inspection
(either by smoke or reflected light) of the heat exchanger
for leaks after the furnace is installed. The furnace access
panel must always be in place when the furnace is operating
and it must not allow leaks into the supply air duct system.
In platform installations with bottom return air, the furnace
should be sealed airtight to the return air plenum. A
door must never be used as a portion of the return air
duct system. The base must provide a stable support
and an airtight seal to the furnace. Allow absolutely no
sagging, cracks, gaps, etc..
Return Air Plenum
NOTE: Return air must not be drawn from a room where
this furnace, or any other gas fueled appliance (i.e., water
heater), or carbon monoxide producing device (i.e., wood
fireplace) is installed.
The return and supply air duct systems must never be
connected to or from other heating devices such as a
fireplace or stove, etc.. Fire, explosion, carbon
monoxide poisoning, personal injury and/or property
damage could result.
When return air is drawn from a room, a negative pressure
is created in the room. If a gas appliance is operating in a
room with negative pressure, the flue products can be pulled
back down the vent pipe and into the room. This reverse
flow of the flue gas may result in incomplete combustion
and the formation of carbon monoxide gas. This toxic gas
might then be distributed throughout the house by the furnace
duct system.
WARNING
The inner blower panel must be securely in place when
the blower and burners are operating. Gas fumes,
which could contain carbon monoxide, can be drawn
into living space resulting in personal injury or death.
Filters
This unit is not equipped with a filter or rack. A field provided
high velocity filter is required for the unit to operate properly.
Table 1 lists recommended filter sizes.
A filter must be in place any time the unit is operating.
Page 12 of 65
In upflow applications, the return air can be brought in through
the bottom or either side of the furnace. If a furnace with
bottom return air is installed on a platform, make an airtight
seal between the bottom of the furnace and the platform to
ensure that the unit operates properly and safely. Use
fiberglass sealing strips, caulking, or equivalent sealing
method between the plenum and the furnace cabinet to
ensure a tight seal. If a filter is installed, size the return air
duct to fit the filter frame.
Issue 1235
506891-01
Venting
A 4 inch diameter flue transition is factory installed on the
combustion air inducer outlet of all models. Figure 16 shows
the combustion air inducer as shipped from the factory.
Mounting Screws Location
If necessary reposition the combustion air inducer, pressure
switch and/or make-up box as needed per the following
steps. See Figures 16 through 22.
1. Remove the four mounting screws (Figure 15) which
secure the combustion air inducer / pressure switch
assembly to the orifice plate. Lift the assembly and rotate it
90° clockwise or counter clockwise to either the 3 o’clock
position or 9 o’clock position. Resecure with four secrews.
Gasket should be left in place.
2. Use tin snips to cut preferred opening on the cabinet for
repositioning the flue outlet. Use the cut-out piece as a cover
plate to patch unused opening on cabinet.
UPFLOW POSITION
Left Side Vent Discharge
Figure 15
UPFLOW POSITION
Top Vent Discharge
•
•
Remove make-up box assembly (2 screws) and cut wire tie to free makeup box wires. Reinstall make-up box on other side of cabinet.
Resecure make-up box wires: Either pull excess wires through the blower
companrtment and secure using supplied wire tie, or coil excess wire and
secure to the gas manifold.
Figure 17
UPFLOW POSITION
Right Side Vent Discharge
Figure 16
IMPORTANT
The unit will not vent properly with the flue transition
pointed down in the 6 o’clock position.
The combustion air inducer may be rotated clockwise
or counterclockwise by 90° to allow for top or side vent
discharge in all applications. When the unit is installed,
the flue transition must be in the 9 o’clock, 12 o’clock or
3 o’clock position.
•
Pressure switch tubing may be too long. Cut to fit, then reattach to barbed
fitting on pressure switch. Tubing must not be allowed to sag.
Figure 18
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Horizontal Position
HORIZONTAL LEFT POSITION
Top Vent discharge
•
•
HORIZONTAL RIGHT POSITION
Top Vent Discharge
Disconnect pressure switch hose from barbed fitting on the pressure
switch assembly. Remove pressure switch assembly (1 screw) and cut
wire tie to free pressure switch wires. Reinstall pressure switch on the
other side of orifice plate and reconnect pressure switch hose.
Resecure pressure switch wires: Either pull excess wires through the
blower compartment and secure using supplied wire tie, or coil excess
wire and secure to the gas manifold.
•
•
Remove make-up box assembly (2 screws) and cut wire tie to free makeup box wires. Reinstall make-up box on other side of cabinet.
Resecure make-up box wires: Either pull excess wires through the blower
compartment and secure using supplied wire tie, or coil excess wire and
secure to the gas manifold.
Figure 21
Figure 19
HORIZONTAL LEFT POSITION
Side Vent Discharge
•
•
HORIZONTAL RIGHT POSITION
Side Vent Discharge
Disconnect pressure switch hose from barbed fitting on the pressure
switch assembly. Remove pressure switch assembly (1 screw) and cut
wire tie to free pressure switch wires. Reinstall pressure switch on the
other side of orifice plate and reconnect pressure switch hose.
Resecure pressure seitch wires: Either pull excess wires through the
blower compartment and secure using supplied wire tie, or coil excess
wire and secure to the gas manifold.
Figure 22
Figure 20
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These series units are classified as fan assisted Category I
furnaces when vertically vented according to the latest edition
of National Fuel Gas Code (NFPA 54 / ANSI Z223.1) in the
USA. A fan assisted Category I furnace is an appliance
equipped with an integral mechanical means to either draw
or force combustion products through the combustion
chamber and/or heat exchanger. This unit is not approved
for use with horizontal venting.
NOTE: Use these instructions as a guide. They do not
supersede local codes. This furnace must be vented
according to all local codes, these installation instructions,
and the provided venting tables in these instructions.
The venting tables in this manual were extracted from the
National Fuel Gas Code (NFPA 54 / ANSI Z223.1) and are
provided as a guide for proper vent installation. Proper
application, termination, construction and location of vents
must conform to local codes having jurisdiction. In the
absence of local codes, the NFGC serves as the defining
document.
Refer to the tables and the venting information contained in
these instructions to properly size and install the venting
system.
IMPORTANT
Once the venting system is installed, attach the
“Disconnected Vent” warning sticker to a visible area of
the plenum near the vent pipe. See Figure 23. The
warning sticker is provided in the bag assembly. Order
kit 66W04 for additional stickers.
WARNING
Use self drilling sheet metal screws or a mechanical fastener
to firmly secure the vent pipe to the round collar of the flue
transition. If self drilling screws are used to attach the vent
pipe, it is recommended that three be used. Drive one self
drilling screw through the front and one through each side
of the vent pipe and collar. See Figure 23.
Install the first vent connector elbow at a minimum of six
inches (152 mm) from the furnace vent outlet. See Figure
23.
Venting Using a Masonry Chimney
The following additional requirements apply when a lined
masonry chimney is used to vent this furnace.
Masonry chimneys used to vent Category I central furnaces
must be either tile lined or lined with a listed metal lining
system or dedicated gas vent. Unlined masonry chimneys
are prohibited. See Figures 24 and 25 for common venting.
A chimney with one or more sides exposed to the outside of
the structure is considered to be an exterior chimney.
An exterior masonry chimney that is not tile lined must be
lined with B1 vent or a listed insulated flexible metal vent.
An exterior tile lined chimney that is sealed and capped may
be lined with a listed uninsulated flexible metal vent.
If the existing chimney will not accommodate a listed metal
liner, either the chimney must be rebuilt to accommodate
one of these liners or an alternate approved venting method
must be found.
Insulation for the flexible vent pipe must be an encapsulated
fiberglass sleeve recommended by the flexible vent pipe
manufacturer. See Figure 24.
Asphyxiation hazard. The exhaust vent for this furnace
must be securely connected to the furnace flue transitiion
at all times.
Common Venting Using Metal Lined
Masonry Chimney
Vent Connection
NOTE 1: Refer to the provided venting tables for installations.
Refer to the capacity requirements shown in the provided venting
tables.
Figure 24
Figure 23
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Common Venting Using Tile Lined Interior Masonry Chimney and Combined Vent Connector
NOTE: Refer to provided venting
tables for installations.
NOTE: The chimney must be properly sized
per provided venting tables or lined with
listed metal lining system.
Figure 25
DO NOT insulate the space between the liner and the
chimney wall with puffed mica or any other loose granular
insulating material.
IMPORTANT
SINGLE appliance venting of a fan assisted furnace into
a tile lined masonry chimney (interior or outside wall) is
prohibited. The chimney must first be lined with either
type B1 vent or an insulated single wall flexible vent
lining system which has been sized according to the
provided venting tables and the vent pipe manufacturer’s
instructions.
Never connect a Category I appliance to a chimney that is
servicing a solid fuel appliance. If a fireplace chimney flue
is used to vent this appliance, the fireplace opening must be
permanently sealed.
A type B or listed chimney lining system that passes through
an unused masonry chimney flue is not considered to be
exposed to the outdoors.
A fan assisted furnace may be commonly vented into an
existing lined masonry chimney if the following conditions
are met:
• The chimney is currently serving at least one drafthood
equipped appliance.
• The vent connectors and chimney are sized according
to the provided venting tables.
If type B1 double wall vent is used inside a chimney, no
other appliance can be vented into the chimney. The outer
wall of type B1 vent pipe must not be exposed to flue
products. A type B1 vent or masonry chimney liner shall
terminate above the roof surface with a listed cap or a listed
roof assembly according to the terms of their respective
listings and the vent manufacturer’s instructions.
When inspection reveals that an existing chimney is not safe
for the intended purpose, it shall be rebuilt to conform to
nationally recognized standards, lined or relined with suitable
materials, or replaced with a gas vent or chimney suitable
for venting. The chimney passageway must be checked
periodically to ensure that it is clear and free of obstructions.
Page 16 of 65
Do not install a manual damper, barometric draft regulator,
or flue restrictor between the furnace and the chimney.
General Venting Requirements
Vent these furnaces according to these instructions:
1. Vent diameter recommendations and maximum
allowable piping runs are found in the provided venting
tables.
2. In no case should the vent or vent connector diameter
be less than the diameter specified in the provided
venting tables.
3. The minimum vent capacity determined by the sizing
tables must be less than the low fire input rating and the
maximum vent capacity must be greater than the high
fire input rating.
4 . Single appliance vents - If the vertical vent or tile lined
chimney has a larger diameter or flow area than the
vent connector, use the vertical vent diameter to
determine the minimum vent capacity and the vent
connector diameter to determine the maximum vent
capacity. The flow area of the vertical vent, however,
shall not exceed 7 times the flow area of the listed
appliance categorized vent area, drafthood outlet area
or flue collar area unless designed according to
approved engineering methods.
5. Multiple appliance vents - The flow area of the largest
section of vertical vent or chimney shall not exceed 7
times the smallest listed appliance categorized vent
area, drafthood outlet area or flue collar area unless
designed according to approved engineering methods.
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506891-01
6. The entire length of single wall metal vent connector
shall be readily accessible for inspection, cleaning, and
replacement.
7. Single appliance venting configurations with zero lateral
lengths (Tables 3 and 4) are assumed to have no elbows
in the vent system. For all other vent configurations,
the vent system is assumed to have two 90° elbows.
For each additional 90° elbow or equivalent (for example
two 45° elbows equal one 90° elbow) beyond two, the
maximum capacity listed in the venting table should be
reduced by 10% (0.90 x maximum listed capacity).
8. The common venting Tables (5, 6, 7, and 8) were
generated using a maximum horizontal vent connector
length of 1-1/2 feet (.46 m) for each inch (25 mm) of
connector diameter as follows:
Table 2
9. If the common vertical vent is offset, the maximum
common vent capacity listed in the common venting
tables should be reduced by 20%, the equivalent of two
90° elbows (0.80 x maximum common vent capacity).
The horizontal length of the offset shall not exceed
1-1/2 feet (.46 m) for each inch (25 mm) of common
vent diameter.
10. The vent pipe should be as short as possible with the
least number of elbows and angles required to complete
the job. Route the vent connector to the vent using the
shortest possible route.
11. A vent connector shall be supported without any dips or
sags and shall slope a minimum of 1/4 inch (6.4 mm)
per linear foot (305 mm) of connector, back toward the
appliance.
12. Vent connectors shall be firmly attached to the furnace
flue collar by self drilling screws or other approved
means,except vent connectors of listed type B vent
material which shall be assembled according to the
manufacturer’s instructions. Joints between sections
of single wall connector piping shall be fastened by
screws or other approved means.
506891-01
13. When the vent connector used for Category I appliances
must be located in or pass through a crawl space, attic
or other areas which may be cold, that portion of the
vent connector shall be constructed of listed doublewall
type B vent material or material having equivalent
insulation qualities.
14. All venting pipe passing through floors, walls, and
ceilings must be installed with the listed clearance to
combustible materials and be fire stopped according to
local codes. In absence of local codes, refer to NFGC
(2223.1 ).
15. No portion of the venting system can extend into, or
pass through any circulation air duct or plenum.
16. Vent connectors serving Category I appliances shall not
be connected to any portion of mechanical draft systems
operating under positive pressure such as Category III
or IV venting systems.
17. If vent connectors are combined prior to entering the
common vent, the maximum common vent capacity
listed in the common venting tables must be reduced by
10%, the equivalent of one 90° elbow (0.90 x maximum
common vent capacity).
18. The common vent diameter must always be at least as
large as the largest vent connector diameter.
19. In no case, shall the vent connector be sized more than
two consecutive table size diameters over the size of
the draft hood outlet or flue collar outlet.
20. Do not install a manual damper, barometric draft
regulator or flue restrictor between the furnace and the
chimney.
21. When connecting this appliance to an existing dedicated
or common venting system, you must inspect the venting
system’s general condition and look for signs of
corrosion. The existing vent pipe size must conform to
these instructions and the provided venting tables. If
the existing venting system does not meet these
requirements, it must be resized.
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Capacity of Type B Double Wall Vents with Type B Double Wall Connectors
Serving a Single Category I Appliance
NOTE: Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent
configurations, the vent system is assumed to have two 90 ° elbows. For each additional 90° elbow or equivalent (for example two 45° elbows equal
one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maximum listed capacity).
Table 3
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Capacity of Type B Double Wall Vents with Single Wall Metal Connectors
Serving a Single Category I Appliance
NOTE: Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent
configurations, the vent system is assumed to have two 90 ° elbows. For each additional 90° elbow or equivalent (for example two 45° elbows equal
one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maximum listed capacity).
Table 4
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Vent Connector Capacity
Type B Double Wall Vents with Type B Double Wall Connectors
Serving Two or More Category I Appliances
Table 5
Common Vent Capacity
Type B Double Wall Vents with Type B Double Wall Connectors
Serving Two or More Category I Appliances
Table 6
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Vent Connector Capacity
Type B Double Wall Vents with Single Wall Metal Connectors
Serving Two or More Category I Appliances
NOTE: Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent
configurations, the vent system is assumed to have two 90 ° elbows. For each additional 90° elbow or equivalent (for example two 45° elbows equal
one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maximum listed capacity).
Table 7
Common Vent Capacity
Type B Double Wall Vents with Single Wall Metal Connectors
Serving Two or more Category I Appliances
Table 8
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Removal of the Furnace from Common Vent
In the event that an existing furnace is removed from a
venting system commonly run with separate gas appliances,
the venting system is likely to be too large to properly vent
the remaining attached appliances.
Conduct the following test while each appliance is operating
and the other appliances (which are not operating) remain
connected to the common venting system. If the venting
system has been installed improperly, you must correct the
system as indicated in the general venting requirements
section.
WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each
appliance connected to the venting system being placed
into operation could result in carbon monoxide poisoning
or death.
3. Close all building doors and windows and all doors
between the space in which the appliances remaining
connected to the common venting system are located
and other spaces of the building. Turn on clothes dryers
and any appliances not connected to the common
venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they will
operate at maximum speed. Do not operate a summer
exhaust fan. Close fireplace dampers.
4. Follow the lighting instructions. Turn on the appliance
that is being inspected. Adjust the thermostat so that
the appliance operates continuously.
5. After the burners have operated for 5 minutes, test for
leaks of flue gases at the draft hood relief opening. Use
the flame of a match or candle.
6. After determining that each appliance connected to the
common venting system is venting properly, (step 3)
return all doors, widows, exhaust fans, fireplace
dampers, and any other gas burning appliances to their
previous mode of operation.
7. If a venting problem is found during any of the preceding
tests, the common venting system must be modified to
correct the problem.
The following steps shall be followed for each appliance
connected to the venting system being placed into operation,
while all other appliances connected to the venting system
are not in operation:
Resize the common venting system to the minimum vent
pipe size determined by using the appropriate tables in
Appendix G. (These are in the current standards of the
National Fuel Gas Code ANSI 2223.1.
1. Seal any unused openings in the common venting
system.
2. Inspect the venting system for proper size and horizontal
pitch. Determine that there is no blockage, restriction,
leakage, corrosion, or other deficiencies which could
cause an unsafe condition.
Page 22 of 65
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Gas Piping
CAUTION
If a flexible gas connector is required or allowed by the
authority that has jurisdiction, black iron pipe shall be
installed at the gas valve and extend outside the furnace
cabinet. The flexible connector can then be added
between the black iron pipe and the gas supply line.
Gas Supply
1. This unit is shipped standard for left or right side
installation of gas piping (or top entry in horizontal
applications). Connect the gas supply to the piping
assembly.
2. When connecting the gas supply piping, consider factors
such as length of run, number of fittings, and furnace
rating to avoid excessive pressure drop. Table 9 lists
recommended pipe sizes for typical applications.
3. The gas piping must not run in or through air ducts,
clothes chutes, gas vents or chimneys, dumb waiters,
or elevator shafts.
4. The piping should be sloped 1/4 inch (6.4 mm) per 15
feet (4.57 m) upward toward the meter from the furnace.
The piping must be supported at proper intervals [every
8 to 10 feet (2.44 to 3.01 m)] with suitable hangers or
straps. Install a drip leg in vertical pipe runs to the unit.
5. A 1/8" N.P.T. plugged tap or pressure post is located on
the gas valve to facilitate test gauge connection. See
Figure 38.
6. In some localities, codes may require the installation of
a manual main shut off valve and union (furnished by
the installer) external to the unit. The union must be of
the ground joint type.
IMPORTANT
Compounds used on threaded joints of gas piping must
be resistant to the actions of liquified petroleum gases.
NOTE: If emergency shutoff is necessary, shut off the main
manual gas valve and disconnect main power to the furnace.
The installer should properly label these devices.
Gas Pipe Capacity - ft³/hr (m³/hr)
Note: Capacity given in cubic feet (m³) of gas per hour and based on 0.60 specific gravity gas.
Table 9
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NOTE: BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET
Figure 26
Horizontal Applications
Possible Gas Piping Configurations
NOTE: BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET
Figure 27
Page 24 of 65
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Leak Check
After gas piping is completed, carefully check all piping
connections (factory and field installed) for gas leaks. Use
a leak detecting solution or other preferred means.
NOTE: If emergency shutoff is necessary, shut off the main
manual gas valve and disconnect the main power to the
furnace. The installer should properly label these devices.
The unit is equipped with a field make-up box on the left
hand side of the cabinet. The make-up box may be moved
to the right side of the furnace to facilitate installation. If the
make-up box is moved to the right side, clip the wire ties
that bundle the wires together. The excess wire must be
pulled into the blower compartment. Secure the excess wire
to the existing harness to protect it from damage.
INTERIOR MAKE-UP BOX INSTALLATION
CAUTION
Some soaps used for leak detection are corrosive to
certain metals. Carefully rinse piping thoroughly after
leak test has been completed. Do not use matches,
candles, flame or other sources of ignition to check for
gas leaks.
The furnace must be isolated by closing its individual manual
shut-off valve and disconnecting from from the gas supply
system the during any pressure testing of the gas supply
system at pressures less than or equal to 1/2 psig (3.48
kPa, 14 inches w.c.).
Figure 29
IMPORTANT
INTERIOR MAKE-UP BOX INSTALLATION
When testing pressure of gas lines, gas valve must be
disconnected and isolated. See Figure 28. Gas valves
can be damaged if subjected to pressures greater than
1/2 psig (3.48 kPa, 14 inches w.c.).
Figure 30
Figure 28
Refer to Figure 40 for schematic wiring diagram and
troubleshooting and Figure 41 for field wiring.
Electrical
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic
components. Take precautions during furnace
installation and service to protect the furnace’s electronic
controls. Precautions will help to avoid control exposure
to electrostatic discharge by putting the furnace, the
control and the technician at the same electrostatic
potential. Neutralize electrostatic charge by touching
hand and all tools on an unpainted unit surface, such
as the gas valve or blower deck, before performing any
service procedure.
506891-01
1. The power supply wiring must meet Class I restrictions.
Protected by either a fuse or circuit breaker, select circuit
protection and wire size according to unit nameplate.
NOTE: Unit nameplate states maximum current draw.
Maximum over current protection allowed is shown in Table
10.
2. Holes are on both sides of the furnace cabinet to facilitate
wiring.
3. Install a separate (properly sized) disconnect switch near
the furnace so that power can be turned off for servicing.
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Page 25 of 65
3. When there is a cooling demand, the indoor blower will
run on the cooling speed designated by the positions of
DIP switches (A, B, C, D) of the COOL jumper plug.
Table 10
4. Before connecting the thermostat, check to make sure
the wires will be long enough for servicing at a later
date. Make sure that thermostat wire is long enough to
facilitate future removal of blower for service.
5. Complete the wiring connections to the equipment. Use
the provided unit wiring diagram and the field wiring
diagram shown in Figure 41. Use 18 gauge wire or
larger that is suitable for Class II rating for thermostat
connections.
6. Electrically ground the unit according to local codes or,
in the absence of local codes, according to the current
National Electric Code (ANSI/NFPA No. 70). A green
ground wire is provided in the field make-up box.
Generator Use - Voltage Requirements
The following requirements must be kept in mind when
specifying a generator for use with this equipment:
• The furnace requires 120 volts ± 10% (Range: 108 volts
to 132 volts).
• The furnace operates at 60 Hz ± 5% (Range: 57 Hz to
63 Hz).
• The furnace integrated control requires both polarity and
proper ground. Both polarity and proper grounding
should be checked before attempting to operate the
furnace on either permanent or temporary power.
• Generator should have a wave form distortion of less
than 5% RHD.
Electrical Wiring
WARNING
NOTE: This furnace contains electronic components that
are polarity sensitive. Make sure that the furnace is wired
correctly and is properly grounded.
7. One line voltage “EAC” 1/4" spade terminal is provided
on the furnace integrated control. Any electronic air
cleaner or other accessory rated up to one amp can be
connected to this terminal with the neutral leg of the
circuit being connected to one of the provided neutral
terminals. See Figure ?? for control configuration. This
terminal is energized when the indoor blower is
operating.
8. One line voltage “HUM” 1/4" spade terminal is provided
on the furnace integrated control. Any humidifier rated
up to one amp can be connected to this terminal with
the neutral leg of the circuit being connected to one of
the provided neutral terminals. See Figure ?? for control
configuration. This terminal is energized in the heating
mode whenever the combustion air inducer is operating.
9. Install the room thermostat according to the instructions
provided with the thermostat. If the furnace is being
matched with a heat pump, refer to the instruction
packaged with the dual fuel thermostat.
Indoor Blower Speeds
1. When the thermostat is set to “FAN ON,” the indoor
blower will run continuously at approximately 50% of
the second stage cooling speed when there is no cooling
or heating demand.
2. When this unit is running in the heating mode, the indoor
blower will run on the heating speed designated by the
positions of DIP switches 1 (A,B,C,D) of the HEAT
jumper plug.
Page 26 of 65
Risk of electrical shock. Disconnect electrical power at
the circuit breaker or service panel before making
electrical connections. Failure to disconnect power
supplies can result in property damage, personal injury,
or death.
The furnace must be grounded and wired in accordance
with local codes or, in the absence of local codes, with the
National Electrical Code ANSI/NFPA No. 70 (latest edition)
and/or CSA C22.1 Electrical Code (latest edition) if an
external electrical source is utilized.
In all instances, other than wiring for the thermostat, the
wiring to be done and any replacement of wire shall conform
with the temperature limitation for Type T wire –63°F (35°C)
rise.
Connect a sufficiently sized wire with ground to the furnace’s
line voltage connections and ground wire. Refer to the
furnace rating plate for electrical characteristics to be used
in sizing field supply wiring and overcurrent protection.
The line voltage supply should be routed through a readily
accessible disconnect located within sight of the furnace. A
junction box on the furnace side panel is provided for line
voltage connections. Refer to the furnace wiring diagram
for specific connection information.
Proper polarity of the supply connections (“HOT” and
“NEUTRAL”) must be observed to ensure that safety
controls provide the protection intended.
A connection to the unit’s ground wire and actual earth ground
(typically a ground stake or buried steel pipe) must be
maintained for proper operation.
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506891-01
Figure 31
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Optional Accessories for use with any ConfortSync® System
Figure 32
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A80US2V Field Wiring Applications with Conventional Thermostat
* Not required on all units.
Table 11A
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A80US2V Field Wiring Applications with Conventional Thermostat (continued)
* Not required on all units.
Table 11B
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A80US2V Field Wiring Applications with Conventional Thermostat (continued)
* Connect W1 to W1 ONLY if using defrost tempering kit 67M41
NOTE: Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the A80
integrated control.
Table 11C
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A80US2V Field Wiring Applications with Conventional Thermostat (continued)
* Connect W1 to W1 ONLY if using defrost tempering kit 67M41
NOTE: Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the A80
integrated control.
Table 11D
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A80US2V Schematic Wiring Diagram
Figure 33
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Typical A80US2V Field Wiring Diagram
Figure 34
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Integrated Control
Figure 35
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Integrated Control DIP Switch Settings - Conventional
Thermostat (non-communicating)
A95US2V units are equipped with a two-stage, variable
speed integrated control. This control manages ignition
timing, heating mode fan off delays and indoor blower
speeds based on selections made using the control dip
switches and jumpers. The control includes an internal
watchguard feature which automatically resets the ignition
control when it has been locked out. After one hour of
continuous thermostat demand for heat, the watchguard
will break and remake thermostat demand to the furnace
and automatically reset the control to relight the furnace.
NOTE: All ComfortSync® settings are set at the
ComfortSync® thermostat. See ComfortSync® installation
instruction. InComfortSync® communication system all DIP
switch and clippable link settings are ignored. For
conventional thermostats proceed with DIP switch and
clippable link settings as outlined in the following.
Heating Operation DIP Switch Settings
Switch 1 - Thermostat Selection — This unit may be used
with either a single-stage or two-stage thermostat. The
thermostat selection is made using a DIP switch which must
be properly positioned for the particular application. The
DIP switch is factory-positioned for use with a two-stage
thermostat. If a single-stage thermostat is to be used, the
DIP switch must be repositioned.
blower OFF delay to achieve a supply air temperature
between 90° and 110°F at the exact moment that the blower
is de-energized. Longer OFF delay settings provide lower
supply air temperatures; shorter settings provide higher
supply air temperatures. Table 10 provides the blower OFF
timings that will result from differentswitch settings.
Blower OFF Delay Switch Settings
B lo w er O ff D elay
(S eco n d s)
60
90 (F actory)
120
180
Switch 2 — Second Stage Delay
(Used with Single-Stage Thermostat Only) — This switch
is used to determine the second stage on delay when a
single-stage thermostat is being used. The switch is factoryset in the OFF position, which provides a 7-minute delay
before second-stage heat is initiated. If the switch is toggled
to the ON position, it will provide a 12-minute delay before
second-stage heat is initiated. This switch is only activated
when the thermostat selector jumper is positioned for
SINGLE- stage thermostat use.
Switches 3 and 4 — Blower-Off Delay — The blower-ON
delay of 30 seconds is not adjustable. The blower OFF
delay (time that the blower operates after the heating
demand has been satisfied) can be adjusted by moving
switches 3 and 4 on the integrated control. The unit is
shipped from the factory with a blower-OFF delay of 90
seconds. The blower OFF delay affects comfort and is
adjustable to satisfy individual applications. Adjust the
blower OFF delay to achieve a supply air temperature
between 90° and 110°F at the exact moment that the blower
is de-energized. Longer OFF delay
Page 36 of 65
S w itch 4
On
O ff
O ff
On
O ff
O ff
On
On
Table 12
Indoor Blower Operation DIP Switch Settings
Switches 5 and 6 — Cooling Mode Blower Speed
The unit is shipped from the factory with the dip switches
positioned for high speed (4) indoor blower motor operation
during the cooling mode. Table 11 provides the cooling
mode blower speeds that will result from different switch
settings. Switches 5 and 6 set the blower cfm for secondstage cool. The integrated control automatically ramps down
to 70% of the second-stage cfm for first-stage cfm. Refer
to tables for corresponding cfm values.
Cooling Mode Blower Speeds
S p ee d
Low
M edium Lo w
M edium H igh
H iqh (F actory)
Select “OFF for two-stage heating operation controlled
by a two-stage heating thermostat (factory setting);
Select “ON” for two-stage heating operation controlled
by a single-stage heating thermostat. This setting
provides a timed delay before second-stage heat
is initiated.
S w itch 3
S w itch 5
On
O ff
On
O ff
S w itch 6
On
On
O ff
O ff
Table 13
Switches 7 and 8 — Cooling Blower Speed Adjustment
The unit is shipped from the factory with the dip switches
positioned for NORMAL (no) adjustment. The dip switches
may be positioned to adjust the blower speed by +10% or
-10% to better suit the application. Table 12 below provides
blower speed adjustments that will result from different
switch settings. Refer to tables for corresponding cfm
values.
Cooling Blower Speed Adjustment
A d ju stm en t
+10% (ap pro x.)
F actory D efault
-10% (appro x.)
S w itch 7
On
O ff
O ff
S w itch 8
O ff
O ff
On
Table 14
Switches 9 and 10 — Cooling Mode Blower Speed
Ramping — Blower speed ramping may be used to
enhance dehumidification performance. The switches are
factory set at option A which has the greatest effect on
dehumidification performance. Table 13 provides the
cooling mode blower speed ramping options that will result
from different switch settings. The cooling mode blower
speed ramping options are detailed on the next page.
NOTE: The off portion of the selected ramp profile also
applies during heat pump operation in dual fuel applications.
Issue 1235
506891-01
Ramping Option 0
• Motor runs at 100% until demand is satisfied.
• Once demand is met, motor ramps down to stop.
Cooling Mode Blower Speed Ramping
R am p in g O p tio n
A (F actory)
B
C
D
S w itch 9
O ff
O ff
On
On
S w itch 10
O ff
On
O ff
On
Table 15
Ramping Option A (Factory Selection)
• Motor runs at 50% for 30 seconds.
• Motor then runs at 82% for approximately 7-1/2 minutes.
• If demand has not been satisfied after 7-1/2 minutes,
motor runs at 100% until demand is satisfied.
• Once demand is met, motor runs at 50% for 30 seconds
then ramps down to stop.
Switches 11, 12 and 13 — Heating Mode Blower Speed
The switches are factory set to the OFF position which
provides factory default heat speed. Refer to Table 14 for
switches 11, 12 and 13 that provided the corresponding
increases or decrease to both high and low heat demand.
Heating Mode Blower Speeds
S w itch
S w itch
S w itch
11
12
13
On
On
On
On
On
O ff
Increase 12%
On
O ff
On
Increase 6%
On
O ff
O ff
F actory D efault
O ff
O ff
O ff
D ecrease 6%
O ff
O ff
On
D ecrease 12%
O ff
On
O ff
D ecrease18%
O ff
On
On
H eat S p e ed
Increase 24%
Ramping Option B
• Motor runs at 82% for approximately 7-1/2 minutes. If
demand has not been satisfied after 7-1/2 minutes,
motor runs at 100% until demand is satisfied.
• Once demand is met, motor ramps down to stop.
Increase 18%
Table 16
Ramping Option C
• Motor runs at 100% until demand is satisfied.
• Once demand is met, motor runs at 100% for 45
seconds then ramps down to stop.
Switches 14 and 15 - Continuous Blower Speed
Table 15 provides continuous blower speed adjustments that
will result from different switch settings.
Continuous Blower Speed
C o n tin u o u s
S w itch 14
S w itch 15
O ff
On
O ff
O ff
70% of H igh C o ol S pee d
On
O ff
100% of H igh C ool S pe ed
On
On
B lo w er S p eed
28% of H igh C o ol S pee d
38% of H igh C o ol S pee d
(F actory)
Table 17
506891-01
Issue 1235
Page 37 of 65
On-Board Links
NOTE: In systems with a conventional outdoor unit (noncommunicating), the on-board clippable links must be set to
properly configure the system.
On-Board Link W915 2 Stage Compr (Y1 to Y2)
On-board link W915 is a clippable connection between
terminals Y1 and Y2 on the integrated control. W915 must
be cut if two-stage cooling will be used. If the Y1 to Y2 link
is not cut the outdoor unit will operate in second-stage
cooling only.
Diagnostic LED (Figure 34)
The seven-segment diagnostic LED displays operating
status, target airflow, error codes and other information. The
table beginning on Page ?? lists diagnostic LED codes.
WARNING
Carefully reviews all configuration information provided.
Failure to properly set DIP switches, jumpers and onboard links can result in improper operation!
On-Board Link W914 Dehum or Harmony (R to DS)
On-board link W914, is a clippable connection between
terminals Rand DS on the integrated control. W914 must
be cut when the furnace is installed with either the control
or a thermostat which features humidity control. If the link
is left intact the PMW signal from the control will be blocked
and also lead to control damage. Refer to Table 18 for
operation sequence in applications including A80US2V, a
thermostat which fetures humidity control and a singlespeed outdoor Unit. Table 19 gives the operation sequence
in applications with a two-speed outdoor unit.
On-Board Link W951 Heat Pump (R to 0)
On-board link W951 is a clippable connection between
terminals R and a on the integrated control. W951 must be
cut when the furnace is installed in applications which
include a heat pump unit and a thermostat which features
dual fuel use. If the link is left intact, terminal “0” will remain
energized eliminating the HEAT MODE in the heat pump.
Diagnostic Push Button (Figure ??)
The diagnostic push button is located adjacent to the sevensegment diagnostic LED. This button is used to enable the
Error Code Recall “E” mode and the Flame Signal “F” mode.
Press the button and hold it to cycle through a menu of
options. Every five seconds a new menu item will be
displayed. When the button is released, the displayed item
will be selected. Once all items in the menu have been
displayed, the menu resumes from the beginning until the
button is released.
Error Code Recall Mode
Select “E” from the menu to access the most recent 10
error codes. Select “c” from the Error Code Recall menu to
clear all error codes. Button must be pressed a second time
while “c” is flashing to confirm command to delete codes.
Press the button until a solid “=” is displayed to exit the
Error Code Recall mode.
Flame Signal Mode
Select “F” from the menu to access the flame signal mode.
The integrated control will display the flame current on 7
segment LED in. in micro amps (uA).
Flame signal mode is exited after the following:
•
•
•
Page 38 of 65
Issue 1235
Power is reset
Pressing and holding push button until 3 horizontal lines
“=” are displayed
10 minutes of entering the flame sense mode.
506891-01
OPERATING SEQUENCE
A80US2V, Non-Communicating Thermostat with Humidity Control Feature and Single-Speed Outdoor Unit
O P E R A T IN G
SYSTEM DEMAND
SEQUENCE
T herm ostat D em and
S ystem
S tep
C ondition
SYSTEM RESPONSE
R elative H um idity
W
Y1
0
G
On
On
1
S tatus
D
B low er
C om pressor
CFM
C om m ents
(C O O L)
N O C A LL FO R D E H U M ID IF IC A T IO N
N orm al O peration
1
On
A cceptable
24
VAC
H igh
100%
H igh
100%
C om pressor and indoor
blow er follow therm ostat
dem and
B A S IC M O D E (only active on a Y 1 therm ostat dem and)
N orm al O peration
D ehum idification
C all
1
2
On
On
On
On
On
On
A cceptable
D em and
24
VAC
0
VAC
H igh
70% *
H igh
100%
therm ostat energizes Y 1
and de-energizes 0 on a
call for de -hum idification
P R E C IS IO N M O D E (operates independent of a Y 1 therm ostat dem and)
N orm al O peration
1
On
On
On
A cceptable
24
VAC
D ehum idification
call
0
2
On
On
On
D em and
VAC
D ehum idification
call O N LY
D ehum idification m ode
begins w hen hum idity is
H igh
70% *
H igh
70% *
greater than set point
0
1
On
On
On
D em and
VAC
Jum pers at indoor unit w ith a single stage outdoor unit
W ith C ondensing unit - C ut W 914 (R to O S ) on S ureLight® control
W ith H eat P um p - C ut W 914 (R to D S ) & W 951 (R to 0) on S ureLight® control
therm ostat w ill try to
m aintain room hum idity
setpoint by allow ing the
room space to m aintain a
cooler room therm ostat
setpoint**
* Dehumidification blower speed is 70% of COOL speed for all units.
** In Precision mode, thermostat will maintain room temperature up to 2°F (1.2°C) cooler than room setting.
Table 19
506891-01
Issue 1235
Page 39 of 65
OPERATING SEQUENCE
A80US2V, Non-Communicating Thermostat with Humidity Control Feature and Two-Speed Outdoor Unit
O P E R A T IN G
SEQUENCE
SYSTEM DEMAND
T herm ostat D em and
S ystem
C ondition
SYSTEM RESPONSE
R elative H um idity
S te
p
Y1
Y2
a
G
On
On
W
W
1
2
B low er
C om pressor
CFM
S tatus
D
On
A cceptable
24
VAC
Low
70% *
On
A cceptable
24
VAC
H igh
100%
24
Low
70% *
C om m ents
(C O O L)
N O C AL L F O R D E H U M ID IF IC ATIO N
N orm al O pera tion - Y 1
1
On
N orm al O pera tion - Y 2
2
On
On
C om pressor and indoor
blow er follow therm ostat
dem and
R O O M TH E R M O S T AT C AL L S F O R F IR S T S T AG E C O O L IN G
B A S IC M O D E (only active on a Y 1 therm ostat dem and)
N orm al O pera tion
D ehum idification
C all
1
2
On
On
On
On
On
On
On
A cceptable
D em and
VAC
0
VAC
H igh
70% **
Low
70% *
H igh
70% **
therm ostat energizes Y 2
and de-energizes D on a
call for de -hum idification
P R E C IS IO N M O D E (operates independent of a Y 1 therm ostat dem and)
N orm al O pera tion
D ehum idification
call
1
On
2
On
On
On
On
A cceptable
On
On
D em and
D ehum idification
call O N LY
24
VAC
0
VAC
On
On
On
On
D em and
VAC
greater than set point
therm ostat w ill try to
m aintain room hum idity
0
1
D ehum idification m ode
begins w hen hum idity is
H igh
70% **
setpoint by allow ing the
room space to m aintain a
cooler room therm ostat
setpoint***
R O O M TH E R M O S T AT C AL L S F O R F IR S T AN D S E C O N D S T AG E C O O LIN G
B A S IC M O D E (only active on a Y 1 therm ostat dem and)
N orm al O pera tion
D ehum idification
C all
1
2
On
On
On
On
On
On
On
On
A cceptable
D em and
24
VAC
0
VAC
H igh
100%
H igh
70% **
Low
70% *
H igh
70% **
H igh
70% **
therm ostat energizes Y 2
and de-energizes D on a
call for de -hum idification
P R E C IS IO N M O D E (operates independent of a Y 1 therm ostat dem and)
N orm al O pera tion
D ehum idification
call
D ehum idification
call O N LY
1
On
2
On
1
On
On
On
A cceptable
On
On
On
D em and
On
On
On
D em and
24
VAC
0
VAC
0
VAC
Jum pers at indoor unit w ith a tw o stage outdoor unit
C ut factory jum per from Y 1 to Y 2 or cut W 915 (Y 1 to Y 2)
W ith C ondensing unit - C ut W 914 (R to D S ) on S ureLight® control
W ith H eat P um p - C ut W 914 (R to D S ) & W 951 (R to 0) on S ureLight® control
D ehum idification m ode
begins w hen hum idity is
greater than set point
therm ostat w ill try to
m aintain room hum idity
setpoint by allow ing the
room space to m aintain a
cooler room therm ostat
setpoint***
*Normal operation first stage cooling blower speed is 70% COOL speed.
**Dehumidification blower speed is reduced to 70% of COOL.
Table 20
Page 40 of 65
Issue 1235
506891-01
START-UP
WARNING
For Your Safety, Read Before Operating
If you do not follow these instructions exactly, a fire or
explosion may result causing property damage, personal
injury, or loss of life.
WARNING
Do not use this furnace if any part has been under water.
Immediately call a licensed professional service
technician (or equivalent) to inspect the furnace and to
replace any part of the control system and any gas
control which has been under water.
Gas Valve Operation (Figures 36 and 37)
1. STOP! Read the safety information at the beginning of
this section.
2. Set the thermostat to the lowest setting.
3. Turn OFF all electrical power to the unit.
4. This furnace is equipped with an ignition device which
automatically lights the burners. Do not try to light the
burners by hand.
5. Remove the upper access panel.
6. Move gas valve switch to OFF position. Do not force.
See Figure 36 or 37.
7. Wait five (5) minutes to clear out any gas. If you then
smell gas, STOP! Immediately call your gas supplier
from a neighbor’s phone. Follow the gas supplier’s
instructions. If you do not smell gas go to next step.
WARNING
If overheating occurs or if gas supply fails to shut off,
shut off the manual gas valve to the appliance before
shutting off electrical supply.
CAUTION
White Rodgers Gas Valve
Before attempting to perform any service or
maintenance, turn the electrical power to unit OFF at
disconnect switch.
WARNING
During blower operation, the ECM motor emits energy
that may interfere with pacemaker operation.
Interference is reduced by both the sheet metal cabinet
and distance.
Shown in ON position.
Figure 36
Honeywell Gas Valve
BEFORE LIGHTING 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.
The gas valve on this unit is equipped with a gas control
switch. Use only your hand to move the switch. Never use
tools. If the switch will not turn or if the control switch will not
move by hand, do not try to repair it.
Shown in ON position.
Placing the furnace into operation:
These units are equipped with an automatic ignition system.
Do not attempt to manually light burners on these furnaces.
Each time the thermostat calls for heat, the burners will
automatically light. The ignitor does not get hot when there
is no call for heat on units with an automatic ignition system.
Figure 37
8. Move gas valve switch to ON position. Do not force.
See Figure 36 or 37.
9. Replace the upper access panel.
10. Turn ON all electrical power to the unit.
11. Set the thermostat to desired setting.
NOTE: When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.
506891-01
Issue 1235
Page 41 of 65
12. If the appliance will not operate, follow the instructions
“Turning Off Gas to Unit” and call your service technician
or gas supplier.
Supply Line Pressure
A threaded plug on the inlet side of the gas valve provides
access to the supply pressure tap.
Turning Off Gas to Unit
1. Set the thermostat to the lowest setting.
2. Turn off all electrical power to the unit if service is to be
performed.
3. Remove the upper access panel.
4. Move gas valve switch to OFF position. Do not force.
See Figure 36 or 37.
5. Replace the upper access panel.
White Rodgers Valve:
An inlet post located on the gas valve provides access to
the supply pressure. See Figure 36. Back out the 3/32 hex
screw one turn, connect a piece of 5/16 tubing and connect
to a manometer to measure supply pressure. See Table 23
for supply line pressure.
Failure To Operate
If the unit fails to operate, check the following:
1. Is the thermostat calling for heat?
2. Are access panels securely in place?
3. Is the main disconnect switch closed?
4. Is there a blown fuse or tripped circuit breaker?
5. Is the filter dirty or plugged? Dirty or plugged filters will
cause the limit control to shut the unit off.
6. Is gas turned on at the meter?
7. Is the manual main shut-off valve open?
8. Is the internal manual shut-off valve open?
9. Is the unit ignition system in lock out? If the unit locks
out again, call the service technician to inspect the unit
for blockages.
10. Is pressure switch closed? Obstructed flue will cause
unit to shut off at pressure switch. Check flue and outlet
for blockages.
11. Are flame rollout switches tripped? If flame rollout
switches are tripped, call the service technician for
inspection.
Gas Pressure Adjustment
Furnace should operate at least 5 minutes before checking
gas flow. Determine time in seconds for two revolutions of
gas through the meter. (Two revolutions assures a more
accurate time.) Divide by two and compare to time in Table
21 below. If manifold pressure matches Table 22and rate is
incorrect, check gas orifices for proper size and restriction.
Remove temporary gas meter if installed.
NOTE: Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Take care to replace
pressure tap plug.
SL280
U n it
-0 4 5
-7 0
-9 0
-1 1 0
-1 3 5
G A S M E T E R C L O C K IN G C H A R T
S e c o n d s fo r O n e R e v o lu tio n
N a tu ra l
LP
2 c u ft
1 c u ft
1 c u ft
D ia l
D ia l
D ia l
80
160
200
55
110
136
41
82
102
33
66
82
27
54
68
N a tu ra l-1 0 0 0 b tu /cu ft
Honeywell Valve:
A threaded plug on the inlet side of the gas valve provides
access to the supply pressure tap. Remove the threaded
plug, install a field-provided barbed fitting and connect a
manometer to measure supply pressure. See Table 23 for
supply line pressure. Replace the threaded plug after
measurements have been taken.
Manifold Pressure
NOTE: A pressure test adapter kit is available to facilitate
manifold pressure measurement.
1. Connect test gauge to manifold pressure post tap (Figure
36) or tap (Figure 37) on gas valve.
2. Ignite unit on high fire and let run for 5 minutes to allow
for steady state conditions.
3. After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in Table
23.
4. If necessary, make adjustments. Figures 36 and 37 show
location of high fire adjustment screw.
5. If an adjustment is made on high fire, re-check manifold
pressure on low fire. Do not adjust low fire manifold
pressure. If low fire manifold pressure is more than
1/2" above or below value specified in Table 22, replace
valve.
Proper Combustion
Furnace should operate minimum 15 minutes with correct
manifold pressure and gas flow rate before checking
combustion. Table 22 shows acceptable combustion for ALL
models. The manimum carbon monoxide reading should
not exceed 50 ppm.
2 c u ft
D IA L
400
272
204
164
136
F iring R ate
C 02% F or N at
C 02% F or L.P .
H igh F ire
6.8 - 7.4
7.5 - 9.0
Low F ire
4.2 - 5.7
5.0 - 6.0
Table 22
L P -2 5 0 0 b tu /c u ft
Table 21
Page 42 of 65
Issue 1235
506891-01
OPERATION
High Altitude
The manifold pressure, gas orifice and pressure switch may
require adjustment or replacement to ensure proper
operation at higher altitudes. See Table 23 through 26 for
manifold pressures, pressure switch and gas conversion kits
at all altitudes.
WARNING
For safety, shut unit OFF and remove manometer as
soon as an accurate reading has been obtained. Take
care to replace pressure tap plug.
Manifold Pressure Settings
This is the only permissible derate for these units.
Natural gas high altitude orifice kit required.
3
A natural to L.P./propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the
conversion procedure.
NOTE: Units may be installed at altitudes up to 4500 ft. above sea level without modifications.
1
2
Table 23
High Altitude Pressure Switch Kits
U n it
In p u t
H ig h A ltitu d e
P ress u re S w itc h K it
0- 450 0 ft.
450 1 - 7 500 ft.
750 1 - 1 0,0 00 ft.
070
N o C h an ge
N o C h an ge
73W 35
090
N o C h an ge
69W 56
73W 35
110
N o C h an ge
69W 56
73W 35
135
N o C h an ge
73W 33
73W 34
Table 24
White Rodgers Gas Valve Conversion Kits
Honeywell Gas Valve Conversion Kits
U n it
In p u t
High Altitude
Natural Gas
Orifice Kit
750 1 10,000 ft.
070
N atu ral G as to
L P I P ro p a n e K it
L P /P ro p a n e
to
N atu ral G as
U n it
In p u t
K it
0- 750 0 ft.
750 1 10,000 ft.
0- 750 0 ft.
73W 37
51W 02
73W 38
69W 79
090
73W 37
51W 02
73W 38
69W 79
110
73W 37
51W 02
73W 38
69W 79
135
73W 37
51W 02
73W 38
69W 79
750 1 10,000 ft.
N atu ral G as to
L P I P ro p a n e K it
0-7 50 0 ft.
750 1 10,000 ft.
L P /P ro p a n e
to
N atu ral G as
K it
0- 750 0 ft.
070
73W 37
77W 07
77W 11
77W 09
090
73W 37
77W 07
77W 11
77W 09
110
73W 37
77W 07
77W 11
77W 09
135
73W 37
77W 07
77W 11
77W 09
Table 26
Table 25
506891-01
H ig h A ltitu d e
N atu ral G as
O rific e K it
Issue 1235
Page 43 of 65
OTHER UNIT ADJUSTMENTS
Primary and Secondary Limits
The primary limit is located on the heating compartment
vestibule panel. The secondary limits (if equipped) are
located in the blower compartment, attached to the back
side of the blower. These auto reset limits are factory set
and require no adjustment.
Flame Rollout Switches (Two)
These manually reset switches are located on (or inside of)
the burner box. If tripped, check for adequate combustion
air before resetting.
Pressure Switches
The pressure switch assembly (includes two switches) is
located in the heating compartment adjacent to the
combustion air inducer. These switches check for proper
combustion air inducer operation before allowing ignition trial.
The switches are factory-set and require no adjustment.
Temperature Rise
Place the unit into operation with a second-stage heating
demand. After supply and return air temperatures have
stabilized, check the temperature rise. If necessary, adjust
the heating blower speed to maintain the temperature rise
within the range shown on the unit nameplate. Increase the
blower speed to decrease the temperature rise. Decrease
the blower speed to increase the temperature rise. Failure
to properly adjust the temperature rise may cause erratic
limit operation.
Thermostat Heat Anticipation
Set the heat anticipator setting (if adjustable) according to
the amp draw listed on the wiring diagram that is attached
to the unit.
NOTE: Do not secure the electrical conduit directly to the
air ducts or structure.
Heating Sequence of Operation
Electronic Ignition
The two-stage, variable speed integrated control used in
these units has an added feature of an internal control. The
feature serves as an anutomatic reset device for ignition
control lockout caused by ignition failure.. After one hour of
continuous thermostat demand for heat, the control will break
and remake thermostat demand to the furnace and
sutomatically reset the control to begin the ignition sequence.
Applications Using a Two-Stage Thermostat
A-Heating Sequence - Control Thermostat Selection DIP
switch in “Two Stage” Position (Factory Settling)
1. On a call for heat, thermostat first stage contacts close
sending a signal to the integrated control. The integrated
control runs a self diagnostic program and checks high
temperature limit switches for normally closed contacts
and pressure switches for normally open contacts. The
combustion air inducer is energized at ignition speed,
Which is approximately the same as the inducer speed
at 70 percent firing rate.
2. Once the control receives a signal that the low fire
pressure switch has closed, the combustion air inducer
begins a 15 second prepurge in the ignition speed.
3. After the prepurge is complete, a 20 second initial ignitor
warm up period begins. The combustion air inducer
continues to operate at the ignition speed.
4. After the 20 second warm up period has ended, the gas
valve is energized and ignition occurs. At the same time,
the control module sends a signal to begin an indoor
blower 30 second ON delay. When the delay ends, the
indoor blower motor is energized at a speed that
matches the firing rate. After the 10 second ignition
stabilization delay expires, the inducer speed is adjusted
to the appropriate target rate. The inducer will remain
at the 70 percent speed as long as the thermostat has a
first stage heating demand.
5. If second stage heat is required, the thermostat second
stage heat contacts close and send a signal to the
integrated control. The integrated control initiates a 30
second secon stage recognition delay.
6. At the end of the recognition delay and on all subsequent
calls for heat in the same heating cycle, the intergrated
control energizes the combustion air inducer at high
speed. The control also checks the high fire pressure
switch to make sure it is closed. As the inducer speed
is increased to high, the indoor blower motor is adjusted
to a speed which is appropriate for the target rate.
7. When the demand for high fire (second stage) heat is
satisfied, the gas valve is de-energized and the field
selected indoor blower off delay begins. The combustion
air inducer begins a 20 second post purge period.
8. When the thermostat demand for low-fire (first stage)
heat is satisfied, the gas valve is de-energized and the
field-selected indoor blower OFF delay bergins. The
combustion air inducer begins a 5 second port-purge
period.
9. When the combustion air post purge period is complete,
the inducer, the HUM contacts as well as the 120V ACC
terminals are de-energized. The indoor blower is deenergized at the end of the OFF delay.
NOTE: The ignition control thermostat selection DIP switch
is factory set in the “TWO STAGE” position.
Page 44 of 65
Issue 1235
506891-01
4.
Application Using a Two Stage Thermostat
B - Heating Sequence - Control Thermostat Selection
DIP switch in “Variable Capacity” Position
NOTE: In these applications, two-stage heat will be initiated
by the integrated control if heating demand has not been
satisfied after the field adjustable period (7 or 12 minutes).
1. On a call for heat, thermostat first stage contacts close
sending a signal to the integrated control. The integrated
control runs a self diagnostic program and checks high
temperature limit switches for normally closed contacts
and pressure switches for normally open contacts. The
combustion air inducer is energized at low speed.
2. Once the control receives a signal that the low pressure
switch has closed, the combustion air inducer begins a
15 second prepurge in low speed.
NOTE: If the low fire pressure switch does not close the
combustion air inducer will switch to high fire. After a
15 second pre-purge the high fire pressure switch will
close and the unit will begin operation on high fire. After
10 to 20 seconds of high fire operation the unit will switch
to low fire.
3. After the prepurge is complete, a 20 second initial ignitor
warm-up period begins. The combustion air inducer
continues to opeate at the ignition speed.
After the 20-second warm-up period has ended, the
gas valve is energized on low fire (first stage) and
ignition occurs. At the same time, the control module
sends a signal to begin an indoor blower 30-second
ON-delay. When the delay ends, the indoor blower
motor is energized on the low fire heating speed and
the HUM contacts are energized. The integrated control
also initiates a second-stage on delay (factory-set at 7
minutes; adjustable to 12 minutes).
5. If the heating demand continues beyond the secondstage on delay, the integrated control energizes the
combustion air inducer at high speed. The control also
checks the high fire (second stage) pressure switch to
make sure it is closed. the high fire (second-stage) gas
valve is energized and the indoor blower motor is
energized for operation at the high fire heating speed.
6. When the thermostat heating demand is satisfied, the
combustion air inducer begins a 5-second low speed
post-purge. The field-selected indoor blower off delay
begins. The indoor blower operates at the low-fire
heating speed.
7. When the combustion air post-purge period is complete,
the inducer, the HUM contacts as well as the 120V ACC
terminals are de-energized. The indoor blower is deenergized at the end of the off delay.
Figure 38
Figure 39
506891-01
Issue 1235
Page 45 of 65
SERVICE
Flue And Chimney
1. Check flue pipe, chimney and all connections for
tightness and to make sure there is no blockage.
2. Check unit for proper draft.
WARNING
ELECTRICAL SHOCK, FIRE,
OR EXPLOSION HAZARD.
Electrical
1. Check all wiring for loose connections.
2. Check for the correct voltage at the furnace (furnace
operating). Correct voltage is 120VAC ± 10%.
3. Check amp-draw on the blower motor with inner blower
panel in place.
Failure 10 follow safety warnings exactly could result
in dangerous operation, serious injury, death or property
damage.
Improper servicing could result in dangerous operation,
serious injury, death, or property damage.
Unit Nameplate________Actual ________ _
Before servicing, disconnect all electrlcal power 10
furnace.
When servicing controls, label all wires prior to
disconnecting. Take care 10 reconnect wires correctly.
Verify proper operation after servicing.
At the beginning of each heating season, a qualified
technician should check the system as follows:
Blower
Check the blower wheel for debris and clean if necessary.
The blower motors are prelubricated for extended bearing
life. No further lubrication is needed.
WARNING
The blower access panel must be securely in place
when the blower and burners are operating. Gas fumes,
which could contain carbon monoxide, can be drawn
into living space resulting in personal injury or death.
Cleaning the Heat Exchanger and Burners
NOTE: Use papers or protective covering in front of the
furnace during cleaning.
1. Turn off both electrical and gas power supplies to
furnace.
2. Remove flue pipe and top cap (some applications top
cap can remain) from the unit.
3. Label the wires from gas valve, rollout switches, primary
limit switch and make-up box then disconnect them.
4. Remove the screws that secure the combustion air
inducer/pressure switch assembly to the collector box.
Carefully remove the combustion air inducer to avoid
damaging blower gasket. If gasket is damaged, it must
be replaced to prevent leakage.
5. Remove the collector box located behind the
combustion air inducer. Be careful with the collector
box gasket. If the gasket is damaged, it must be
replaced to prevent leakage.
6. Disconnect gas supply piping. Remove the screw
securing the burner box cover and remove cover.
Remove the four screws securing the burner manifold
assembly to the vestibule panel and remove the
assembly from the unit.
7. Remove screws securing burner box and remove
burner box.
8. NOX units only - Remove screw securing NOX insert.
Filters
All A80US2V filters are installed external to the unit. Filters
should be inspected monthly. Clean or replace the filters
when necessary to ensure that the furnace operates
properly. Replacement filters must be rated for high velocity
airflow. Table 1 lists recommended filter sizes.
Page 46 of 65
Issue 1235
506891-01
A80US2V Burner, Combustion Air Inducer Assembly &
Heat Exchanger Removal
Figure 40
9. Remove screws from both sides, top and bottom of
vestibule panel.
10. Remove heat exchanger. It may be necessary to spread
cabinet side to allow more room. If so, remove five
screws from the left side or right side of cabinet. See
Figure 42.
11. Back wash using steam. Begin from the burner opening
on each clam. Steam must not exceed 275°F.
12. To clean burners, run a vacuum cleaner with a soft brush
attachment over the face of burners. Visually inspect
inside the burners and crossovers for any blockage
caused by foreign matter. Remove any blockage.
Figure 40 shows burner detail.
506891-01
13. To clean the combustion air inducer visually inspect and
using a wire brush clean where necessary. Use
compressed air to clean off debris and any rust.
14. Reinstall heat exchanger in vestibule. (Replace the five
screws in the cabinet from step 10 if removed).
15. NOX units only - replace’ NOX inserst.
16. Reinstall collector box and combustion air assembly.
Reinstall all screws to the collector box and combustion
air inducer. Failure to replace all screws may cause
leaks. Inspect gaskets for any damage and replace if
necessary.
17. Reinstall burner box, manifold assembly and burner box
cover.
Issue 1235
Page 47 of 65
A80US2V NOX Inserts
18. Reconnect all wires.
19. Reconnect top cap and vent pipe to combustion air
inducer outlet.
20. Reconnect gas supply piping.
21. Turn on power and gas supply to unit.
22. Set thermostat and check for proper operation.
23. Check all piping connections, factory and field, for gas
leaks. Use a leak detecting solution or other preferred
means.
CAUTION
Some soaps used for leak detection are corrosive to
certain metals. Carefully rinse piping thoroughly after
leat test has been completed. Do Not use matches,
candles, flame or other sources of ignition to check for
gas leaks.
Figure 41
Remove 5 Screws if necessary
(either side of cabinet)
24. If a leak is detected, shut gas and electricity off and
repair leak.
25. Repeat steps 24 and 26 until no leaks are detected.
26. Replace access panel.
Figure 42
Page 48 of 65
Issue 1235
506891-01
Planned Service
The following items should be checked during an annual inspecation. Power to the unit nmust be shut OFF for the service
technician’s safety.
Fresh air grilles and louvers (on the unit and in the room
where the furnace is installed) - Must be open and
unobstructed to provide combustion air.
Operating performance - Unit must be observed during
operation to monitor proper performance of the unit and
the vent system.
Burners - Must be inspected for rust, dirt, or signs of water.
Combustion gases - Flue products must be analyzed and
compared to the unit specifications.
Vent pipe - Must be inspected for signs of water, damaged
or sagging pipe, or disconnected joints.
Unit appearance - Must be inspected for rust, dirt, signs of
water, burnt or damaged wires, or components.
Blower access panel - Must be properly in place and
provide a seal between the return air and the room where
the furnace is installed.
Return air duct - Must be properly attached and provide
an air seal to the unit.
Problems detected during the inspection may make it
necessary to temporarily shut down the furnace until the
items can be repaired or replaced.
Instruct the homeowners to pay attention to their
furnace. Situations can arise between annual furnace
inspections that may result in unsafe operation. For
instance,items innocently stored next to the furnace may
obstruct the combustion air supply. This could cause
incomplete combustion and the production of carbon
monoxide gas.
Repair Parts List
The following repair parts are available through independent dealers. When ordering parts, include the complete furnace
model number listed on the CSA International nameplate. All service must be performed by a licensed professional installer
(or equivalent), service agency, or gas supplier.
Cabinet Parts
Upper access panel
Blower panel
Top cap
Control Panel Parts
Transformer
Two-stage, variable speed integrated control
Door interlock switch
Circuit breaker
Blower Parts
Blower wheel
Blower housing
Motor
Motor electronics
Power choke (1 hp only)
Motor mounting frame
Motor capacitor
Blower housing cutoff plate
506891-01
Heating Parts
Flame Sensor
Heat exchanger assembly
Gas manifold
Two-speed combustion air inducer
Two-stage gas valve
Main burner cluster
Main burner orifices
Pressure switch
Ignitor
Primary limit control
Flame rollout switch
Secondary limit
Issue 1235
Page 49 of 65
Integrated Control Diagnostic Modes
D isplay
N o chang e (idle)*
S olid"E"
S olid"D"
S olid"F"
S olid"P" ( variable spee d only)
A ction (w hen button release d)
R em ain in idle m od e
E nter diagn ostic recall m ode
D ischarge A ir Installed
E nter flam e signal m ode
P rogram unit capacity/size (U nit C ode)**
* No change implies the display will continue to show whatever is currently being displayed for normal operation (blinking
decimal, active error code, heat state, etc .. )
** After the “P” is selected (by releasing the push button) the integrated control will start flashing the “P” on display for 90
seconds. If push button is pressed again and held during that time, the control will start to display characters corresponding
to different variable speed furnace models for 3 seconds each. While the wanted character-model is displayed push button
has to be released. Selected option will flash display for 1 0 seconds and during that time push button has to be pressed and
held for 5 seconds. Once control accepts new setting it will store data in non-volatile memory and reset itself. If 10 seconds
expires or push button is held less than 5 seconds, control will exit filed test mode and go in idle without programming the
unit size.
Integrated Control Diagnostic Codes
Press the diagnostic push button and hold it to cycle through a menu of options. Every five seconds a new menu item will be
displayed. Release the button when the desired mode is displayed.
When a solid “P” is displayed, the furnace capacity / size is programmed.
When the solid “E” is displayed, the control enters the Diagnostic Recall (Alarm History). Diagnostic Recall mode menu
options: No change (displaying error history) remains in Diagnostic Recall mode; solid” .= “ exits Diagnostic Recall mode;
and solid “c” clears the error history. Must press button while flashing “c” is displayed to clear error codes.
When the solid “F” is displayed, the control enters the Flame Signal Mode. The Flame Signal Mode is exited: with power
cycle/reset, by pressing and holding the push button until 3 horizontal line are displayed “.= “, after 10 minutes of entering
flame signal mode.
Action Required to Clear and Recover
Diagnostic Codes / Status of Equipment
Code
Idle mode (Decimal blinks at 1 Hertz -- 0.5 second ON, 0.5 second OFF).
A
Cubic feet per minute (cfm) setting for indoor blower (1 second ON, 0.5 second OFF) /
cfm setting for current mode displayed.
C
Cooling stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed / Pause / cfm setting
displayed / Pause / Repeat codes).
d
Dehumidification mode (1 second ON) / 1 second OFF) / cfm setting displayed / Pause /
Repeat Codes).
h
Heat pump stage (1 second ON, 0.5 second OFF) / % of input rate displayed / Pause / cfm,
setting / Pause / Repeat codes.
H
Gas Heat Stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed / Pause / cfm, setting
displayed / Pause / Repeat codes. Blinking during ignition.
dF
Defrost mode.
U
Discharge Air Temperature
Page 50 of 65
Issue 1235
506891-01
Integrated Control Diagnostic Codes
C ode
E 105
D iagnostic C odes/S tatus of E quipm ent
A ction R equired to C lear and R ecover
D evice com m unication problem - N o other devices on R S B U S (C om m u nication
system ).
E 110
Low line voltage .
E 1]1
Line voltage po larity reversed.
E 112
G round not detected
E 113
H igh line voltage.
E 114
Line voltage frequency out-of-range.
E 115
Low 24V - C ontrol w ill restart if the error recovers.
E 116
H igh 24V .
E 117
P oor ground detected (W arning only)
E 120
U nresponsive device. C om m unication only.
E 124
A ctive com m unicating therm ostat signal m issing for m ore than 3 m in utes.
E 125
C ontrol failed self-check, internal error, failed hardw are. W ill restart if
error
recovers . Integrated control not com m unicating. C overs hardw are errors
(flam e sense circuit faults , pin shorts , etc.).
C ontrol internal com m unication problem .
E 126
506891-01
Issue 1235
E quipm ent is unable to com m unicate . Indicates
num erous m essage errors. In m ost cases errors are
related to electrical noise. M ake sure high voltage
pow e r is separated from R S B us. C heck for rnis w ired and/or loose connections betw een the stat,
indoor unit and outdoor unit. C heck for a h igh voltage source of noise close to the system . F ault
clears after com m unication is restored .
Line V oltage Low (V O ltage low er than nam eplate
rating). C heck pow er line voltage and correct. A larm
clears 5 seconds after fault recovered .
R everse line pow er voltage w iring. S ystem resum es
norm al operation 5 seconds afte r fault recovered.
S ystem shuts dow n . P rovide proper earth ground.
S ystem resum es norm a l operation 5 seconds after
fault recovered.
Line V oltage H igh (V oltage highe r than nam eplate
rating). P rovide pow er voltage w ith in proper range .
S ystem resum es norm al operation 5 seconds after
fault recovered.
N o 60 H ertz P ow er. C heck voltage and line pow er
frequency. C orrect voltage and frequency problem s .
S ystem resum es norm al operation 5 seconds after
fault recovered.
24-V olt P ow er Lo w (R ange · is 18 to 30 volts). C heck
and correct voltage . C heck for additional pow er-robbing equipm ent connected to system . M ay require
installation of larger V A transform er to be installed in
furnace / air handler. C lears afte r fault recovered .
24 V olt P ow er H igh (R ange is 18 to 30 V O lts ). C heck
and correct voltage . C heck for proper line voltage
(120V , 240V , etc.) to equipm ent. C lears w hen con trol senses proper voltage.
P rovide proper ground ing for unit. C heck for proper
earth ground to the system . W am ing only w ill clear
30 seconds after fault recovered .
U sually caused by delay in outdoor unit responding
to indoor unit poling. R ecycle pow er. C heck all w iring connections. C leared after unresponsive device
responds to any inquiry.
E quipm ent lost com m unication w ith the therm ostat.
C heck four w iring connections , ohm w ires and cycle
pow e r at the therm ostat. A lert stops all services and
w aits for heartbeat m essage from therm ostat (sub net controller). C leared after valid therm ostat (sub net controller) m essage is received.
H ard w are problem on the control. C ycle pow er on
control. R eplace if problem prevents service and is
persistent. C ritical alert. C leared 300 seconds after
fault recovered .
H ard w are problem on the contro l. C ycle pow er on
control. R eplace if problem prevents service and is
persistent. C leared 300 seconds after fault recovered.
Page 51 of 65
Integrated Control Diagnostic Codes (continued)
E 131
C orrupted control param eters (V erify configuration of system ). C om m unicating only.
E 180
O utdoor air tem perature sensor failure. O nly show n if shorted or out-ofrange.
E 200
H ard lockout - R ollout circuit open or previously open.
E201
Indoor blow er com m unication failure - U nable to com m unicate w ith blow er m otor.
E 202
Indoor blow er m otor m is-m atch - Indoor m otor horsepow er does not
m atch unit capacity. S ee P age 67.
E203
A ppliance capacity! size is N O T program m ed. Invalid unit codes refer to
configuration flow chart. S ee P age 6 7.
E204
G as valve m is-w ired.
E 205
G as valve control relay contact shorted.
E 206
G as valve second-stage relay failure
E 207
H ot surface ignitor sensed open - R efer to troubleshooting. S ee P age 68.
Page 52 of 65
Issue 1235
R econfigure the system . R eplace control if heating
or cooling is not availab le. O nly applicable in the
com m unicating m ode, not in startup. E xit from C om m issioning and E xecute 'S et F actory D efau lt m ode'.
C ontrol w ill still operate on defau lt param eter settings.
C om pare outdoor sensor resistance to tem perature!
resistance charts in unit installation instructions.
R eplace sensor pack if necessary. A t beginning of
(any) configuration, furnace or air handler control
w ill sense outdoor air and discharge air tem perature
sensor(s). If detected (reading in range), appropriate feature w ill be set as 'installed' and that could
be seen in 'A bout' screen. In norm al operation after
control recognizes sensors, alarm w ill be sent if
valid tem perature reading is lost. To get rid of setting and alarm , redo configuration and m ake sure
that tem perature senso r is m arked as 'not installed'
in Indoor U nit 'A bout' screen. W hen Indoor unit control is replaced, therm ostat w ill 'tell' new control if
tem perature sensor is in system o r not. C lears 30
seconds after fault recovered.
C orrect cause of rollout trip , or replace flam e rollout
sw itch. T est furnace operation . C leared after fault
recovered.
Indoor blow er com m unication failure (including pow er outage). Lost com m un ication w ith indoor blow er
m otor. P ossible ca uses: m otor not pow ered, loose
w iring. P roblem m ay be on con trol or m otor side.
C leared after fault recove red.
Incorrect appliance capacity code selected. C heck
for proper configuring under: U nit S ize C odes for
F urnace!A ir H a ndler on configuration guide or in
installation instructions. C leared afte r the correct
m atch is detected follow ing a reset. (R em ove therm ostat from system w h ile applying pow er and reprogram m ing.)
N o appliance capacity code selected. C heck for
proper configuring under: U nit S ize C odes for F urnace on configuration guide or in installation instructions. C ritical A le rt. C leared after valid unit code is
read follow ing a reset. (R em ove therm ostat from
system w hile app lying pow er and reprogram m ing.)
C heck gas valve opera tion and w iring . C lears w hen
repaired.
C heck w iring on control an d gas valve. If w iring is
correct, replace control.
F urnace w ill operate on 1 st stage for rem ainder of
the heating dem and . W ill clear after fault recovered.
If unable to ope rate 2nd stage, replace control.
M easure resistance of hot surface ignitor. R eplace if
open or not w ithin specified range found in 10M .
R esum es norm a l operation after fault is cleared.
506891-01
Integrated Control Diagnostic Codes (continued)
C ode
D iagnostic C odes/S tatus of E quipm ent
A ction R equired to C lear and R ecover
E 223
Low pressure sw itch failed open .
E 224
Low pressure sw itch fa iled closed - R efer to troubleshooting .
P age 68.
E 225
H igh pressure sw itch failed open - R efer to troubleshooting .
P age 68.
E 226
H igh pressure sw itch failed closed - R efer to troubleshooting.
P age 68.
E 227
Low pressure sw itch open during trial for ignition o r run m ode. R efer to
troubleshooting. S ee P age 68 .
C heck pressure (inches w .c.) of low pressure sw itch
closing on heat call. M easure operating pressure
(inches w .c.). Inspect vent and com bustion air in ducer for correct operation and restriction . R esum es norm al operation after fault is cleared.
E 228
C om bustion air inducer calibration failure
U nable to perform pressure sw itch calibration.
C heck vent system and pressure sw itch w iring con nections. R esum es norm a l operation after fau lt is
cleared.
E 229
Ignition on high fire
IF C sw itched to h igh fire ignition because low fire
pressure sw itch did not close in allow ed tim e. N o
action is needed.
E 240
Low flam e curren t - R un m ode - R efer to troubleshooting . S ee P age 68 .
C heck m icro-am peres of flam e sensor using control
diagnostics o r field-installed m ode . C lean or rep lace
sensor. M easure voltage of neutra l to ground to e nsure good unit ground . A lert clears after current
heat call has been com pleted.
E 241
F lam e sensed out of sequence - Flam e still present.
S hut off gas. C heck fo r gas valve leak. R eplace , if
necessary. A lert clears w hen fault is recovered.
E 250
Lim it sw itch circuit open - R efer to troubleshooting.
C heck for prope r firing rate on furnace. E nsure
there is no blockage in heater. C heck for proper air
flow . If lim it not closed w ithin 3 m inutes , unit w ill go
into 1-hour soft lockout. R esum es norm al operation
after fau It is cleared.
E 252
D ischarge air tem perature too high (gas heat only).
C heck tem perature rise, air flow and input rate.
C leared w hen heat call is finished .
E 270
S oft lockout - E xceeded m axim um num ber of retries . N o flam e curren t
sensed.
C heck for proper gas flow . E nsure that ign itor is
lighting burner. C heck flam e senso r current. C lears
w hen heat call finishes successfully.
E 271
S oft lockout - E xceeded m axim um num ber of re tries. Last retry failed due
to the pressure sw itch opening .
C heck pressure (inches w .c.) of low pressure sw itch
closing on heat call. M easure operating pressure
(inches w .c .). Inspect vent and com bustion air inducer for correct operation and restriction. C lears
w hen heat call fin ishes successfully.
506891-01
C heck pressure (inches w .c.) of low pressure sw itch
closing on heat call. M easure operating pressure
(inches w .c.). Inspect vent and com bustion a ir inducer for correct operation and restriction . R esum es norm al operation after fault is cleared
S ee
S ee
S ee
Issue 1235
C heck operation o f low pressure sw itch to see if it is
stuck closed on hea t call longer than 150 seconds.
M easure operating pressure (inches w .c.). Inspect
vent and com bustion air inducer for correct operation and restriction. R esum es norm al operation afte r
fault is cleared.
C heck pressure (inches w .c.) of high pressure
sw itch closing on heat call. M easure operating pressure (inches w .c.). Inspect vent and com bustion a ir
inducer for correct operation and restriction. R esum es norm al operation afte r fault is cleared .
C heck operation of high pressure sw itch clos ing on
heat call. M easure operating pressure (inches w .c .).
Inspect vent and com bustion air inducer for correct
operation and restriction . R esum es norm al operation after fault is cleared.
Page 53 of 65
Integrated Control Diagnostic Codes (continued)
E 272
S oft lockout - E xceeded m axim um num ber of recycles. Last recycle due
to the pressure sw itch opening.
C heck operation of low pressure sw itch to see if it is
stuck closed on heat call. C heck pressure (inches
w .c.) of high pressure sw itch c losing on heat call.
M easure operating pressure (inches w .c.). Inspect
vent and com bustion air inducer for correct ope ration and restriction. C lears w hen heat call finishes
successfully.
E 273
S oft lockout - E xceeded m axim um num ber of recycles. Last recycle due
to flam e failure .
C heck m icro -am peres of flam e senso r using control
diagnostics or fie ld-installed m ode. C lean or rep lace
sensor. M easure voltage of neutral to ground to en sure good unit ground. C lears w hen heat call finish es successfully.
E 274
S oft lockout - E xceeded m axim um num ber of recycles. Last recycle
failed due to the lim it circuit opening o r lim it rem ained open longe r than
3 m inutes.
S hut dow n system . 1-hour soft lockout. C heck firing
rate and air flow . C heck for blockage . C lears w hen
heat call finishes successfully.
E 275
S oft lockout - F lam e sensed out of sequence. F lam e signa l is gone.
S hut off gas. C heck for gas valve lea k. 1-hour soft
lockout. C lears w hen flam e has been proven stable.
E 276
W atchguard calibration failure .
U nable to perform pressure sw itch calibration.
C heck vent system and pressure sw itch w iring con nections. 1-hour soft lockout. C lears w hen calibra tion has finished successfully.
E 290
Ignitor circuit fault - F ailed ignitor or triggering circuitry.
M easure resistance of hot surface ignitor. R eplace if
open or not w ithin specifications . 1-hour soft lock out. C lears w hen flam e has been proven stable .
E 291
H eat air flow restricted below the m inim um .
C heck for dirty filter and air flow restriction. C heck
blow er perform ance . 1-hour soft lockout. C leared
w hen heat call finishes successfully.
E 292
Indoor blow er m otor unable to start due to obstructed w hee l, seized
bearings.
Indoor blow er m otor unable to start (seized bearing, stuck w heel, etc.). R eplace m otor or w heel if
assem bly does no t operate or m eet perform ance
standards. 1-hour soft lockout. C lears afte r circulator successfully starts .
E 294
C om bustion air inducer over current.
C heck com bustion blow er bearings , w iring and
am ps. R eplace if does not operate or does not m eet
perform ance standards. C lears after inducer current
is sensed to be in -range after the ignition follow ing
the soft lockout or reset.
E 295
Indoor blow er m otor tem perature is too high.
Indoor blow er m oto r over tem perature (m otor
tripped on internal protector). C heck m otor bearings
and am ps. R eplace if necessary. C leared afte r
blow er dem and is satisfied.
E 310
D ischarge error tem perature sensor failure .
out of range .
E 311
H eat rate reduced to m atch indoor blow e r air flow .
Page 54 of 65
O nly show n if shorted or
C om pare outdoor sensor resistance to tem perature/
resistance charts in installation instructions. R eplace sensor if necessary. C leared in C om m unicating m ode: 30 seconds after fault recovered. In N on C om m unicating m ode: C leared after the current
heat call is com pleted.
W arning O nly. F urnace blow er in cutback m ode due
to restricted airflow . R educe firing rate every 60
seconds to m atch available C F M . C heck filter and
duct system . T o clear, replace filter if needed o r repair/add duct. 2-stage controls w ill reduce firing rate
to 1 st stage. C lears w hen heat call finishes successfully.
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Integrated Control Diagnostic Codes (continued)
C ode
D iagnostic C odes/S tatus of E quipm ent
A ction R equired to C lear and R ecover
E 312
R estricted air flow in cooling or continuous fan m ode is low er than cfm
setting.
W arning O nly. R estricted airflow - Indoor blow er is
running at a reduced C F M (C utback M ode - T he
variable speed m otor has pre -set speed and torque
lim iters to protect the m oto r from dam age caused
by operating outs ide of design param eters (0 to 0.8 "
W .C .. total external static pressure). C heck filter and
duct system . T o clear, replace filter if needed or re pair/add duct. C leared afte r the current service de m and is satisfied .
E 313
Indoor or outdoor unit capacity m ism atch . C om m unication only.
Incorrect indoor/outdoor capacity code selected .
C heck for proper configuring in installation instruc tions. A larm is just a w arning. T he system w ill operate, but m ight not m eet efficiency and capacity pa ram eters. A larm w ill clear w hen com m iss ioning is
exited. C leared after com m issioning is com plete .
E 331
G lobal netw ork connection - C om m unication link prob lem .
F or F uture U se.
E 334
R elay "Y 1" stuck on interated control.
R eplace integrated control.
E 347
N o 24 V olt output on Y 1 of "integrated control" w ith non com m unicating
outdoor unit.
O peration stopped. Y 1 relay / S tage 1 failed . (P ilot
relay contacts did no t close or the relay coil did not
energize; no input back to IF C chip). C ritical A lert.
C leared after reset and Y 1 input sensed.
E 348
N o 24 V olt output on Y 2 of "integrated control" w ith non-com m unicating
outdoor unit.
Y 2 relay / S tage 2 failed. (P ilot relay contacts did
not close or the relay coil did not energize; no input
back to IF C chip). C ritical A lert. C leared after reset
and Y 1 input sensed.
E 349
N o 24 V olts betw een R & 0 on "integrated control" w ith non com m unicating outdoo r unit (D ual fuel m odule requ ired for heat pum p application).
C onfiguration link R to 0 needs to be restored . R eplace link or hard-w ire. A pplicable in non com m unicating m ode . C ritical A lert.
E 370
Interlock sw itch sensed open for 2 m inutes.
C ontrol sees the loss of 24V A C fo r 2 m inutes .T erm inate all services and w ait for interloc k sw itch to
close. T he alarm w ill c lear w hen 24V A C is continu ously sensed on D S term inal for a m inim um of 10
seconds or on a pow er reset.
E 400
LS O M - C om pressor internal overload tripped .
T herm ostat dem and Y 1 is present; but, com pressor
is not running . C heck pow er to outdoor unit. C lears
the error after current is sensed in both R U N and
S T A R T sensors fo r at least 2 seconds, or after service is rem oved ; or after pow e r reset.
E 401
LS O M C om pressor long run cycle or low system pressure.
C om pressor ran m o re than 18 hours to satisfy a
single therm osta t dem and. C ritical A lert. C lears the
error after 30 consecutive norm al run cycles or
pow e r reset. A lso m onitors low pressure sw itch
trips.
E 402
LS O M - O utdoor unit system pressure trip.
D ischarge or suction pressure out-of-lim its, or com pressor overloaded. C lears the error after 4 consec utive norm al com pressor run cyc les.
E 403
LS O M - C om pressor short-cycling .. (R unning less than 4 m inutes). O utdoor unit pressure trip
C om pressor runs less than 3 m inutes to satisfy a
therm ostat dem and . C lears the e rror after 4 consecutive norm al run cycles o r pow er reset.
E 404
LS O M - C om pressor
less than 4 m inutes).
C om pressor rotor locked up due to ru n capacitor
short, bearings are se ized, excessive liquid refrigerant, etc. C lears the erro r after 4 consecutive norm a l
run cycles or afte r pow er reset.
E 40 5
LS O M - C om pressor open circuit.
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rotor locked. C om pressor short-cycling. (R unning
C om pressor circuit open (due to pow e r d isconnection, open fuse, etc.) C lears the error after 1 norm al
com pressor run cycle .
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Integrated Control Diagnostic Codes (continued)
E406
LS O M - C om pressor open start circuit.
R equired am ount of current is not passing through
S tart current transform er. C lears the error after current is sensed in S T A R T sensor, or after pow er re set.
E 407
LS O M - C om pressor open run circuit.
R equired am ount of current is not passing through
R un current transform er. C lears the error after current is sensed in R U N sensor, or 1 norm al com p ressor run cycle, or after pow er reset.
E 408
LS O M - C om pressor contactor is w elded.
C om pressor runs continuously. C lears the e rror
after 1 norm al com pressor run cycle o r after pow er
reset.
E 409
LS O M - C om pressor low voltage.
S econdary voltage is below 18V A C . A fter 10 m inutes, operation is d iscontinued. C lears the code
after voltage is highe r than 20 V A C fo r 2 seconds or
after pow er reset.
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Program Unit Capacity / Size Mode
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Troubleshooting: Heating Sequence of Operation
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Troubleshooting: Heat Sequence of Operation (continued)
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Troubleshooting: Heat Sequence of Operation (continued)
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Troubleshooting: Heat Sequence of Operation (continued)
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Troubleshooting: Continuous Fan Sequence of Operation
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START-UP & PERFORMANCE CHECK LIST
UNIT SET UP
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UNIT OPERATION
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