Bryant 312AAV/JAV User Manual

312AAV/JAV
2--STAGE DELUXE, INDUCED COMBUSTION
4--WAY MULTIPOISE GAS FURNACE

Installation, Start--up, Operating and

Service and Maintenance Instructions

Series 140/E

SAFETY CONSIDERATIONS 2........................

INTRODUCTION 3..................................

CODES AND STANDARDS 5..........................

Safety 5...........................................

General Installation 5................................

Combustion and Ventilation Air 5......................

Duct Systems 5.....................................

Acoustical Lining and Fibrous Glass Duct 5...............

Gas Piping and Gas Pipe Pressure Testing 5...............

Electrical Connections 5..............................

Venting 5.........................................

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS

PROCEDURE 5.....................................

LOCATION 6.......................................

AIR FOR COMBUSTION AND VENTILATION 7.........

INSTALLATION 10..................................

UPFLOW INSTALLATION 10......................

DOWNFLOW INSTALLATION 11...................

HORIZONTAL INSTALLATION 11..................

FILTER ARRANGEMENT 15.......................

AIR DUCTS 15...................................

GAS PIPING 17..................................

ELECTRICAL CONNECTIONS 21..................

VENTING 26....................................

START--UP, ADJUSTMENT, AND SAFETY CHECK 33.....

General 33........................................

Start--Up Procedures 34..............................

Adjustments 34.....................................

Check Safety Controls 39.............................

Checklist 39.......................................

SERVICE AND MAINTENANCE PROCEDURES 44.....

Introduction 44...................................

Care and Maintenance 45...........................

Sequenceof Operation 49...........................

Wiring Diagrams 52...............................

Troubleshooting 52................................

Accessory List 55.................................

PARTS REPLACEMENT INFORMATION GUIDE 56.....

I

G

S

E

N

D

C

E

E

R

I

T

F

I

Use of the AHRI Certified TM Mark indicates a
manufacturer’s participation in the program. For
verification of certification for individual products,
go to www.ahridirectory.org.

ISO 9001:2000

D

REGISTERED

Always Ask For

NOTE: Read the entire instruction manual before starting the
installation.

Portions of the text and tables are reprinted from NFPA 54/ANSI
Z223.1--2009E, with permission of National Fire Protection
Association, Quincy, MA 02269 and American Gas Association,
Washington DC 20001. This reprinted material is not the
complete and official position of the NFPA or ANSI on the
referenced subject, which is represented only by the standard in
its entirety.

A

B

[736.9]

29

Ø7/8

[22.2]

ACCESSORY

5 15/16
[150.7]

28.39

[721.2]

Ø7/8

[22.2]

ACCESSORY

14 7/8
[337.3]

(BOTH SIDES)

Ø7/8
[22.2]
ACCESSORY

Ø7/8

[22.2]

ACCESSORY

Ø1 3/4
[44.5]
GAS ENTRY

Ø1/2
[12.7]
THERMOSTAT WIRE ENTRY

22 1/16

[560]

SIDE INLET

(BOTH SIDES)

11 7/16
[290.7]

9 11/16
[245.4]

[197.8]

7 13/16

Ø7/8
[22.2]

J.BOX PROVISION

Ø7/8
[22.2]
JUNCTION BOX
LOCATION

Ø1 3/4
[44.5]
GAS ENTRY

1 15/16
[49.2]

1

[25.4]

1 1/4
[31.8]

29 9/16
[750.7]

1 15/16

[49.2]

5 5/8

[143.3]

5 7/16

[138.5]

6 13/16
[172.3]

Ø1/2

[12.7]

THERMOSTAT WIRE ENTRY

19

[481.7]

OUTLET

D

21.6

[549.5]

BOTTOM INLET

C

33 1/4

[843.9]

9 9/16
[243.3]

3/4

[19.1]

5 7/8
[148.5]

3 7/16
[86.8]

9 7/8

[250.7]

27 3/4
[704.7]

2 5/16
[59]

FRONT OF CASING

TOP OF CASING

4 13/16
[122.2]

27 3/4
[704.7]

5 7/8

[148.5]

8 5/8
[219]

5 1/2
[140.3]

8 7/16
[213.5]

FRONT OF CASING

TOP OF CASING

6.1

[155.7]

2 1/16
[51.6]

5.1

5.1

[130.5]

1.7
[43.5]

Ø7/8
[22.2]
ACCESSORY (2)

AIR FLOW

AIR FLOW

BOTTOM RETURN

WIDTH

AIR FLOW

KNOCK OUTS FOR
VENTING(5
PLACES)

[130.5]

2 1/16
[51.6]

1.7
[43.5]

Ø7/8
[22.2]
ACCESSORY (2)

FRONT OF CASING

8 5/8
[219]

6 13/16

FRONT OF CASING

1 15/16
[49.2]

5 15/16
[150.7]

5 1/2
[140.3]

8 7/16
[213.5]

9 7/8

[250.7]

27 3/4
[704.7]

33 1/4

[843.9]

312AAV

NOTES:

1. Two additional 7/8 --- in. (22 mm) diameter holes are located in the top plate.

2. Minimum return ---air openings at furnace, based on metal duct. If flex duct is used, see flex duct manufacturer’s recommendations for equivalent diameters.

AIR FLOW

ACCESSORY

THERMOSTAT WIRE ENTRY

ACCESSORY

21.6

[549.5]

BOTTOM INLET

28.39

[721.2]

29

[736.9]

Ø7/8

[22.2]

Ø7/8

[22.2]

Ø1/2

[12.7]

6.1

[155.7]

3 7/16
[86.8]

5 7/8
[148.5]

2 5/16
[59]

TOP OF CASING

Ø7/8
[22.2]
JUNCTION BOX
LOCATION

Ø1 3/4
[44.5]
GAS ENTRY

AIR FLOW

A

BOTTOM RETURN

WIDTH

TOP OF CASING

3/4

[19.1]

29 9/16
[750.7]

27 3/4
[704.7]

KNOCK OUTS FOR
VENTING(5
PLACES)

[148.5]

5 7/16

[138.5]

4 13/16
[122.2]

9 9/16
[243.3]

J.BOX PROVISION

ACCESSORY

5 7/8

[172.3]

[143.3]

1 15/16

[49.2]

Ø7/8

[22.2]

Ø7/8

[22.2]

5 5/8

AIR FLOW

19

[481.7]

OUTLET

Ø1/2
[12.7]
THERMOSTAT WIRE ENTRY

Ø1 3/4
[44.5]
GAS ENTRY

Ø7/8
[22.2]
ACCESSORY

22 1/16

[560]

SIDE INLET

(BOTH SIDES)

a. For 800 CFM---16 ---in. (406 mm) round or 14 1/2 x 12---in. (368 x 305 mm) rectangle.

b. For 1200 CFM---20 ---in. (508 mm) round or 14 1/ 2 x 19 1/2 ---in. (368 x 495 mm) rectangle.

c. For 1600 CFM---22 ---in. (559 mm) round or 14 1/ 2 x 22 1/16 ---in. (368 x 560mm) rectangle.

d. For airfl ow requirements above 1800 C FM, see Air Delivery table in Product Data literature for specific use of single side inlets. The use of both sideinlets,

a combination of 1 side and the bottom, or the bottom only will ensure adequate return air openings f o r airflow requirements above 1800 CFM.

7 13/16

[197.8]

14 7/8
[337.3]

(BOTH SIDES)

[25.4]

9 11/16
[245.4]

1 1/4
[31.8]

A10290

11 7/16
[290.7]

Fig. 1 -- Dimensional Drawing

Table 1 – Dimensions -- In. (mm)

A

FURNACE SIZE

045 ---08/024045 14--- 3/16 (360) 12---9/16 (319) 9--- 5/16 (237) 12---11/16 (322) 4 (102) 104 (47) 16 (406)
045 ---12/036045 14--- 3/16 (360) 12---9/16 (319) 9--- 5/16 (237) 12---11/16 (322) 4 (102) 107 (49) 16 (406)
070 ---08/024070 14--- 3/16 (360) 12---9/16 (319) 9--- 5/16 (237) 12---11/16 (322) 4 (102) 111 (50) 16 (406)
070 ---12/036070 14--- 3/16 (360) 12---9/16 (319) 9--- 5/16 (237) 12---11/16 (322) 4 (102) 115 (52) 16 (406)
070 ---16/048070 17---1/2 (445) 15--- 7/8 (403) 11--- 9/16 (294) 16 (406) 4 (102) 126 (57) 16 (406)
090 ---14/042090 17---1/2 (445) 15--- 7/8 (403) 11--- 9/16 (294) 16 (406) 4 (102) 127 (58) 16 (406)
090 ---16/048090 21 (533) 19 --- 3/8 (492) 13--- 5/16 (338) 19--- 1/2 (495) 4 (102) 140 (64) 20 (508)
090 ---20/060090 21 (533) 19 --- 3/8 (492) 13--- 5/16 (338) 19--- 1/2 (495) 4 (102) 146 (66) 20 (508)

CABINET

WIDTH

B

OUTLET WIDTH

110 ---12/036110 17---1/2 (445) 15--- 7/8 (403) 11--- 9/16 (294) 16 (406) 4 (102) 135 (61) 16 (406)
110 ---16/048110 21 (533) 19 --- 3/8 (492) 13--- 5/16 (338) 19--- 1/2 (495) 4 (102) 146 (66) 20 (508)
110 ---22/066110 21 (533) 19 --- 3/8 (492) 13--- 5/16 (338) 19--- 1/2 (495) 4 (102) 152 (69) 20 (508)
135 ---16/048135 21 (533) 19 --- 3/8 (492) 13--- 5/16 (338) 19--- 1/2 (495) 4 (102){ 149 (68) 20 (508)
135 ---22/066135 24---1/2 (622) 22--- 7/8 (581) 15--- 1/16 (383) 23 (584) 4 (102){ 163 (74) 24 (610)
155 ---20/060155 24---1/2 (622) 22--- 7/8 (581) 15--- 1/16 (383) 23 (584) 4 (102){ 170 (77) 24 (610)

*135 and 155 size furnaces require a 5 or 6---in. (127 or 152 mm) vent. Use a vent adapter between furnace and vent stack. See Installation Instructions for
complete installation requirements.

C

TOP &

BOTTOM FLUE

COLLAR

2

D

BOTTOM

INLET WIDTH

VENT

CONNECTION

SIZE

SHIP WT

LB (KG)

ACCESSORY

FILTER MEDIA

CABINET

SAFETY CONSIDERATIONS

!

WARNING

FIRE, EXPLOSION, ELECTRICAL SHOCK, AND
CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in dangerous
operation, serious injury, death, or property damage.

Improper installation, adjustment, alteration, service,
maintenance, or use could cause carbon monoxide
poisoning, explosion, fire, electrical shock, or other
conditions which may cause personal injury or property
damage. Consult a qualified service agency, local gas
supplier, or your distributor or branch for information or
assistance. The qualified service agency must use only
factory--authorized and listed kits or accessories when
modifying this product.

!

FURNACE RELIABILITY HAZARD

Improper installation or misapplication of furnace may
require excessive servicing or cause premature component
failure.

Application of this furnace should be indoors with special
attention given to vent sizing and material, gas input rate,
air temperature rise, unit leveling, and unit sizing.

!

CUT HAZARD

Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care

and wear appropriate protective clothing, safety glasses and
gloves when handling parts, and servicing furnaces.

Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical shock, or
other conditions which may cause death, personal injury, or
property damage. Consult a qualified installer, service agency, or
your distributor or branch for information or assistance. The
qualified installer or agency must use factory--authorized kits or
accessories when modifying this product. Refer to the individual
instructions packaged with the kits or accessories when installing.

Follow all safety codes. Wear safety glasses, protective clothing,
and work gloves. Have a fire extinguisher available. Read these
instructions thoroughly and follow all warnings or cautions
include in literature and attached to the unit. Consult local
building codes, the current editions of the National Fuel Gas
Code (NFGC) NFPA 54/ANSI Z223.1 and the National
Electrical Code (NEC) NFPA 70.

Recognize safety information. This is the safety--alert symbol
When you see this symbol on the unit and in instructions or
manuals, be alert to the potential for personal injury.

Understand the signal words DANGER, WARNING,and

CAUTION. These words are used with the safety--alert symbol.
DANGER identifies the most serious hazards which will result in

severe personal injury or death. WARNING signifies hazards
which could result in personal injury or death. CAUTION is
used to identify unsafe practices which may result in minor
personal injury or product and property damage. NOTE is used
to highlight suggestions which will result in enhanced
installation, reliability, or operation.

CAUTION

CAUTION

.

product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.

1. Use only with type of gas approved for this furnace. Refer
to the furnace rating plate.

2. Install this furnace only in a location and position as spe­cified in the “Location” section of these instructions.

3. Provide adequate combustion and ventilation air to the
furnace space as specified in “Air for Combustion and
Ventilation” section.

4. Combustion products must be discharged outdoors. Con­nect this furnace to an approved vent system only, as spe­cified in the “Venting” section of these instructions.

5. Never test for gas leaks with an open flame. Use a com­mercially available soap solution made specifically for the
detection of leaks to check all connections, as specified in
the “Gas Piping” section.

6. Always install furnace to operate within the furnace’s in­tended temperature--rise range with a duct system which
has an external static pressure within the allowable range,
as specified in the “Start--Up, Adjustments, and Safety
Check” section. See furnace rating plate.

7. When a furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space con­taining the furnace, the return air shall also be handled by
duct(s) sealed to the furnace casing and terminating out­side the space containing the furnace. See “Air Ducts” sec­tion.

8. A gas--fired furnace for installation in a residential garage
must be installed as specified in the warning box in the
“Location” section.

9. The furnace may be used for construction heat provided
that the furnace installation and operation complies with
the first CAUTION in the LOCATION section of these in­structions.

10. These Multipoise Gas--Fired Furnaces are CSA (formerly
A.G.A. and C.G.A.) design--certified for use with natural
and propane gases (see furnace rating plate) and for install­ation in alcoves, attics, basements, closets, utility rooms,
crawlspaces, and garages. The furnace is factory--shipped
for use with natural gas. A CSA (A.G.A. and C.G.A.) lis­ted accessory gas conversion kit is required to convert fur­nace for use with propane gas.

11. See Fig. 2 for required clearances to combustible construc­tion.

12. Maintain a 1--in. (25 mm) clearance from combustible ma­terials to supply air ductwork for a distance of 36 inches
(914 mm) horizontally from the furnace. See NFPA 90B
or local code for further requirements.

13. These furnaces SHALL NOT be installed directly on car­peting, tile, or any other combustible material other than
wood flooring. In downflow installations, factory access­ory floor base MUST be used when installed on combust­ible materials and wood flooring. Special base is not re­quired when this furnace is installed on manufacturer’s
Coil Assembly Part No. CAR, CAP, CNRV, CNPV or
when Coil Box Part No. KCAKC is used. See Fig. 2 for
clearance to combustible construction information.

INTRODUCTION

The Series 140/E 4--way multipoise Category I fan--assisted
furnace is CSA (formerly A.G.A. and C.G.A.) design--certified. A
Category I fan--assisted furnace is an appliance equipped with an
integral mechanical means to either draw or force products of
combustion through the combustion chamber and/or heat
exchanger. The furnace is factory--shipped for use with natural

312AAV

3

gas. This furnace is not approved for installation in mobile
homes, recreational vehicles, or outdoors.

These furnaces shall not be installed directly on carpeting, tile, or
any other combustible material other than wood flooring. For
downflow installations, a factory accessory floor base must be
used when installed on combustible materials and wood flooring.
This special base is not required when this furnace is installed on
the manufacturer’s coil assembly, or when the manufacturer’s coil
box is used. See Fig. 2 for clearance to combustible material
information.

This furnace is designed for minimum continuous return--air
temperature of 60_F(16_C) db or intermittent operation down to

312AAV

55_F(13_C) db such as when used with a night setback
thermostat. Return--air temperature must not exceed 80_F(27_C)
db. Failure to follow these return--air temperature limits may
affect reliability of heat exchangers, motors, and controls. (See
Fig. 3.)

For accessory installation details, refer to the applicable
instruction literature.

NOTE: Remove all shipping brackets and materials before
operating the furnace.

Fig. 2 -- Clearances to Combustibles

4

A10269

80 / 27 C

60

/ 16 C

A06745

Fig. 3 -- Return Air Temperature

CODES AND STANDARDS

Follow all national and local codes and standards in addition
to these instructions. The installation must comply with

regulations of the serving gas supplier, local building, heating,
plumbing, and other codes. In absence of local codes, the
installation must comply with the national codes listed below and
all authorities having jurisdiction.

In the United States, follow all codes and standards for the
following:

Step 1 — Safety

National Fuel Gas Code (NFGC) NFPA 54--2009/ANSI
Z223.1--2009 and the Installation Standards, Warm Air Heating
and Air Conditioning Systems ANSI/NFPA 90B

Step 2 — General Installation

Current edition of the NFGC and the NFPA 90B. For copies,
contact the National Fire Protection Association Inc.,
Batterymarch Park, Quincy, MA 02269; (www.NFPA.org) or for
only the NFGC, contact the American Gas Association, 400 N.
Capitol Street, N.W., Washington DC 20001 (www.AGA.org.)

Step 3 — Combustion and Ventilation Air

Section 9.3 of the NFGC, NFPA 54/ ANSI Z223.1--2009 Air for
Combustion and Ventilation

Step 4 — Duct Systems

Air Conditioning Contractors Association (ACCA) Manual D,
Sheet Metal and Air Conditioning Contractors National
Association (SMACNA), or American Society of Heating,
Refrigeration, and Air Conditioning Engineers (ASHRAE) 2001
Fundamentals Handbook Chapter 34 or 2000 HVAC Systems
and Equipment Handbook Chapters 9 and 16.

Step 5 — Acoustical Lining and Fibrous Glass Duct

Current edition of SMACNA and NFPA 90B as tested by UL
Standard 181 for Class I Rigid Air Ducts

Step 6 — Gas Piping and Gas Pipe Pressure Testing

NFPA 54 / ANSI Z223.1--2009; chapters 5, 6, 7, and 8 and
National Plumbing Codes

Step 7 — Electrical Connections

National Electrical Code (NEC) ANSI/NFPA 70--2008

Step 8 — Venting

NFGC; NFPA 54 / ANSI Z223.1--2009 chapters 12 and 13

ELECTROSTATIC DISCHARGE (ESD)

PRECAUTIONS PROCEDURE

!

CAUTION

FURNACE RELIABILITY HAZARD

Improper installation or service of furnace may cause
premature furnace component failure.

Electrostatic discharge can affect electronic components.
Follow the Electrostatic Discharge Precautions Procedure
listed below during furnace installation and servicing to
protect the furnace electronic control. Precautions will
prevent electrostatic discharges from personnel and hand
tools which are held during the procedure. These
precautions will help to avoid exposing the control to
electrostatic discharge by putting the furnace, the control,
and the person at the same electrostatic potential.

1. Disconnect all power to the furnace. Multiple disconnects
may be required. DO NOT TOUCH THE CONTROL OR
ANY WIRE CONNECTED TO THE CONTROL PRIOR
TO DISCHARGING YOUR BODY’S
ELECTROSTATIC CHARGE TO GROUND.

2. Firmly touch the clean, unpainted, metal surface of the fur­nace chassis which is close to the control. Tools held in a
person’s hand during grounding will be satisfactorily dis­charged.

3. After touching the chassis, you may proceed to service the
control or connecting wires as long as you do nothing to
recharge your body with static electricity (for example;
DO NOT move or shuffle your feet, do not touch un­grounded objects, etc.).

4. If you touch ungrounded objects (and recharge your body
with static electricity), firmly touch a clean, unpainted
metal surface of the furnace again before touching control
or wires.

5. Use this procedure for installed and uninstalled (ungroun­ded) furnaces.

6. Before removing a new control from its container, dis­charge your body’s electrostatic charge to ground to pro­tect the control from damage. If the control is to be in­stalled in a furnace, follow items 1 through 4 before
bringing the control or yourself in contact with the fur­nace. Put all used and new controls into containers before
touching ungrounded objects.

7. An ESD service kit (available from commercial sources)
mayalsobeusedtopreventESDdamage.

312AAV

5

THE BLOWER IS LOCATED

TO THE RIGHT OF THE

BURNER SECTION, AND

AIR CONDITIONED AIR IS

DISCHARGED TO THE LEFT.

THE BLOWER IS

LOCATED BELOW THE

BURNER SECTION, AND

CONDITIONED AIR IS

DISCHARGED UPWARD.

THE BLOWER IS

LOCATED ABOVE THE

BURNER SECTION, AND

312AAV

CONDITIONED AIR IS

DISCHARGED DOWNWARD

LOCATION

GENERAL

This multipoise furnace is shipped in packaged configuration.
Some assembly and modifications are required when used in any
of the four applications shown in Fig. 4.

NOTE: For high--altitude installations, the high--altitude
conversion kit MUST be installed at or above 5500 ft. (1676 M)
above sea level. Obtain high--altitude conversion kit from your
area authorized distributor.

This furnace must:
S be installed so the electrical components are protected from

water.

S not beinstalled directly onany combustible material other than

wood flooring for upflow applications. Downflow installations
require use of a factory--approved floor base or coil assembly
when installed on combustible materials or wood flooring (refer
to SAFETY CONSIDERATIONS).

S be located close to the chimney or vent and attached to an air

distribution system. Refer to Air Ducts section.

S be provided ample space for servicing and cleaning. Always

comply with minimum fire protection clearances shown on the
furnace clearance to combustible construction label.

The following types of furnace installations may require
OUTDOOR AIR for combustion due to chemical exposures:

S Commercial buildings
S Buildings with indoor pools
S Laundry rooms
S Hobby or craft rooms, and
S Chemical storage areas

If air is exposed to the following substances, it should not be used
for combustion air, and outdoor air may be required for

combustion:

S Permanent wave solutions
S Chlorinated waxes and cleaners
S Chlorine based swimming pool chemicals

Fig. 4 -- Multipoise Orientations

S Water softening chemicals
S De--icing salts or chemicals
S Carbon tetrachloride
S Halogen type refrigerants
S Cleaning solvents (such as perchloroethylene)
S Printing inks, paint removers, varnishes, etc.
S Hydrochloric acid
S Cements and glues
S Antistatic fabric softeners for clothes dryers

S Masonry acid washing materials

CARBON MONOXIDE POISONING AND UNIT
DAMAGE HAZARD

Failure to follow this warning could result in personal
injury or death, and furnace damage.

Corrosive or contaminated air may cause failure of parts
containing flue gas, which could leak into the living space.
Air for combustion must not be contaminated by halogen
compounds, which include fluoride, chloride, bromide, and
iodide. These elements can corrode heat exchangers and
shorten furnace life. Air contaminants are found in aerosol
sprays, detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products. Do not install
furnace in a corrosive or contaminated atmosphere. Make
sure all combustion and circulating air requirements are met,
in addition to all local codes and ordinances.

All fuel--burning equipment must be supplied with air for fuel
combustion. Sufficient air must be provided to avoid negative
pressure in the equipment room or space. A positive seal must be
made between the furnace cabinet and the return--air duct to
prevent pulling air from the burner area and from draft safeguard
opening.

!

WARNING

THE BLOWER IS

LOCATED TO THE LEFT

OF THE BURNER SECTION,

AND CONDITIONED AIR IS

DISCHARGED TO THE RIGHT.

A02097

6

!

WARNING

!

CAUTION

FIRE, INJURY OR DEATH HAZARD

Failure to follow this warning could result in personal
injury, death, and/or property damage.

When the furnace is installed in a residential garage, the
burners and ignition sources must be located at least 18
inches (457 mm) above the floor. The furnace must be
located or protected to avoid damage by vehicles. When the
furnace is installed in a public garage, airplane hangar, or
other building having a hazardous atmosphere, the furnace
must be installed in accordance with the NFGC. (See Fig.

5.)

18-IN. (457.2 mm)

MINIMUM TO BURNERS

A93044

Fig. 5 -- Installation in a Garage

!

WARNING

FIRE HAZARD

Failure to follow this warning could result in personal
injury, death and/or property damage.

Do not install the furnace on its back or hang furnace with
control compartment facing downward. Safety control
operation will be adversely affected. Never connect
return--air ducts to the back of the furnace. (See Fig. 6.)

PROPERTY DAMAGE HAZARD

Improper use or installation of this furnace may cause
premature component failure. This gas furnace may be used
for construction heat provided that:

--The furnace is permanently installed with all electrical
wiring, piping, venting and ducting installed according to
these installation instructions. A return air duct is provided,
sealed to the furnace casing, and terminated outside the
space containing the furnace. This prevents a negative
pressure condition as created by the circulating air blower,
causing a flame roll--out and/or drawing combustion
products into the structure.

--The furnace is controlled by a thermostat. It may not be
”hot wired” to provide heat continuously to the structure
without thermostatic control.

--Clean outside air is provided for combustion. This is to
minimize the corrosive effects of adhesives, sealers and
other construction materials. It also prevents the
entrainment of drywall dust into combustion air, which can
cause fouling and plugging of furnace components.

--The temperature of the return air to the furnace is
maintained between 55_F(13_C) and 80_F(27_C), with
no evening setback or shutdown. The use of the furnace
while the structure is under construction is deemed to be
intermittent operation per our installation instructions.

--The air temperature rise is within the rated rise range on
the furnace rating plate, and the gas input rate has been set
to the nameplate value.

--The filters used to clean the circulating air during the
construction process must be either changed or thoroughly
cleaned prior to occupancy.

--The furnace, ductwork and filters are cleaned as necessary
to remove drywall dust and construction debris from all
HVAC system components after construction is completed.

--Verify proper furnace operating conditions including
ignition, gas input rate, air temperature rise, and venting
according to these installation instructions.

LOCATION RELATIVE TO COOLING EQUIPMENT

The cooling coil must be installed parallel with, or on the
downstream side of the unit to avoid condensation in the heat
exchangers. When installed parallel with the furnace, dampers or
other flow control must prevent chilled air from entering the
furnace. If the dampers are manually operated, they must be
equipped with means to prevent operation of either unit unless
the damper is in the full--heat or full--cool position.

312AAV

Fig. 6 -- Prohibit Installation on Back

AIR FOR COMBUSTION AND

VENTILATION

Provisions for adequate combustion, ventilation, and dilution air
must be provided in accordance with:

U.S. installations: Section 9.3 of the NFPA 54 /A ANSI
Z223.1--2009, Air for Combustion and Ventilation, and
applicable provisions of the local building codes.

A02054

7

!

CAUTION

FURNACE CORROSION HAZARD

Failure to follow this caution may result in furnace damage.
Air for combustion must not be contaminated by halogen

compounds, which include fluoride, chloride, bromide, and
iodide. These elements can corrode heat exchangers and
shorten furnace life. Air contaminants are found in aerosol
sprays, detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products.

!

WARNING

CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in personal
injury or death.

The operation of exhaust fans, kitchen ventilation fans,

312AAV

clothes dryers, attic exhaust fans or fireplaces could create a
NEGATIVE PRESSURE CONDITION at the furnace.
Make--up air MUST be provided for the ventilation devices,
in addition to that required by the furnace. Refer to Carbon
Monoxide Poisoning Hazard warning in venting section of
these instructions to determine if an adequate amount of
make--up air is available.

The requirements for combustion and ventilation air depend upon
whether or not the furnace is located in a space having a volume
of at least 50 cubic feet per 1,000 Btuh input rating for all gas
appliances installed in the space.

S Spaces having less than 50 cubic feet per 1,000 Btuh require the

Outdoor Combustion Air Method.

S Spaces having at least 50 cubic feet per 1,000 Btuh may use the

Indoor Combustion Air, Standard orKnown Air Infiltration
Method.

Outdoor Combustion Air

Method

1. Provide the space with sufficient air for proper combus­tion, ventilation, and dilution of flue gases using perman­ent horizontal or vertical duct(s) or opening(s) directly
communicating with the outdoors or spaces that freely
communicate with the outdoors.

2. Fig. 7 illustrates how to provide TWO OUTDOOR
OPENINGS, one inlet and one outlet combustion and
ventilation air opening, to the outdoors.

e. One opening MUST commence within 12 in. (300 mm)

of the ceiling and the second opening MUST commence
within 12 in. (300 mm) of the floor.

f. Size openings and ducts per Fig. 7 and Table 2.

2

g. TWOHORIZONTALDUCTS require1 --in

per 2,000 Btuh (1,100 mm

2

/kW) of combined input for

of freearea

all gas appliances in the space per Fig.7 and Table 2.

h. TWO OPENINGS OR VERTICAL DUCTS require 1

2

of free area per 4,000Btuh (550mm2/kW) for com-

-- i n
bined input of all gas appliances in the space per Fig. 7
and Table 2.

3. ONE OUTDOOR OPENING requires:

a. One square inch of free area per 3,000 Btuh (734

2

/kW)for combined input of all gas appliancesin the

mm
space per Table 2 and

b. Not less than the sum of the areas of all vent connectors

in the space.

Table 2 – Minimum Free Area Required for Each Combustion Air opening of Duct to Outdoors

FURNACE

INPUT

(BTUH)

44,000 22 (14194) 6 (152) 14.7 (9484) 5 (127) 11 (7096) 4 (102)
66,000 33 (21290) 7 (178) 22 (14193) 6 (152) 16.5 (10645) 5 (127)

88,000 44 (28387) 8 (203) 29.3 (18903) 7 (178) 22 (14193) 6 (152)
110,000 55 (35484) 9 (229) 36.7 (23677) 7 (178) 27.5 (17742) 6 (152)
132,000 66 (42580) 10 (254) 44 (28387) 8 (203) 33 (21290) 7 (178)
154,000 77 (49677) 10 (254) 51.3 (33096) 9 (229) 38.5 (24839) 8 (203)

TWO HORIZONTAL DUC TS SINGLE DUCT OR OPENING TWO OPENINGS OR VERTICAL DUCTS

(1 SQ. IN./2,000 BTUH) (1,100 SQ. MM/KW) (1 SQ. IN./3,000 BTUH) (734 SQ. MM/KW) (1 SQ. IN./4,000 BTUH) (550 SQ. MM/KW)

Free Area of Opening

and Duct

Sq. In. (Sq. mm)

Round Duct

Dia.

In. (mm)

Free Area of Opening

and Duct

Sq. In. (Sq. mm)

Round Duct

Dia.

In. (mm)

Free Area of Opening

and Duct

Sq. In. (Sq. mm)

Round Duct

Dia.

In. (mm)

EXAMPLES: Determining Free Area

FURNACE WATER HEATER TOTAL INPUT

110,000 + 30,000 = (140,000 divided by 4,000) = 35.0 Sq. In. for each two Vertical Ducts or Openings

66,000 + 40,000 = (106,000 divided by 3,000) = 35.3 Sq. In. for a Single Duct or Opening
88,000

+ 30,000 = (118,000 divided by 2,000) = 59.0 Sq. In. for each of two Horizontal Ducts

8

1 SQ IN.

E

12 ″ MAX

(305mm)

1 SQ IN.
PER 4000
BTUH*

PER 4000
BTUH*

F

1 SQ IN .

BTUH*

1 SQ IN .

BTUH*

G

12 ″
MAX

PER

4000

OUTDOORS

PER
4000

12 ″
MAX

DUCTS

TO

O UTDOORS

(305mm)

12 ″ MAX

1 SQ IN.
PER 2000
BTUH*

DUCT S

TO

OUTDOORS

1 SQ IN.
PER 2000
BTUH*

(305mm)

12 ″ MAX

CIRCULA TING AIR DUCT S

*Minimum dimensions of 3 ---in. (76 mm).
Note: Use any of the following combinations of openings:

A&BC&DD&EF&G

B

AIR DUCTS

C IRCULA TING

A

OF COMB USTION AIR

CLEARANCE IN FRONT

D

VENT
THR OUGH
R OOF

(76mm)

AT LEAST 3 IN .

OPENINGS SHALL BE

C

DUCT

TO

OUTDOORS

Fig. 7 -- Air for Combustion, Ventilation, and Dilution for

Outdoors

(305mm)

(305mm)

A03174

CIRCULATING AIR

DUCTS

INTERIOR

HEATED

SPACE

CIRCULATING AIR DUCTS

* Minimum opening size is 100 sq in. (64516 sq. mm) with minimum

dimensions of 3 in. (76 mm)

†Minimumof3in.(76mm)whentype-B1ventisused.

VENT THROUGH ROOF

12" MAX

1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL

UNCONFINED
SPACE

(152mm)

6" MIN
(FRONT)

1 SQ IN.
PER 1000
BTUH* IN DOOR

OPENINGS SHALL BE AT LEAST 3 IN.

OR WALL

CLEARANCE IN FRONT OF COMBUSTION AIR

12" MA X

(305mm)

Ü

(305mm)

A03175

Fig. 8 -- Air for Combustion, Ventilation, and Dilution from

Indoors

312AAV

The opening shall commence within 12 in. (300 mm) of the
ceiling. Appliances in the space shall have clearances of at least 1
in. (25 mm) from the sides and back and 6 in. (150 mm) from the
front. The opening shall directly communicate with the outdoors
or shall communicate through a vertical or horizontal duct to the
outdoors or spaces (crawl or attic) that freely communicate with
the outdoors.

Indoor Combustion Air
Known--Air--Infiltration Rate

E NFPA & AGA Standard and

Methods

Indoor air is permitted for combustion, ventilation, and dilution,
if the Standard or Known--Air--Infiltration Method is used.

!

WARNING

CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in death and/or
personal injury.

Many homes require air to be supplied from outdoors for
furnace combustion, ventilation, and dilution of flue gases.
The furnace combustion air supply must be provided in
accordance with this instruction manual.

The Standard Method:

1. The space has no less volume than 50 cubic feet per 1,000
Btuh of the maximum input ratings for all gas appliances
installed in the space and

2. The air infiltration rate is not known to be less than 0.40
air changes per hour (ACH).

The Known Air Infiltration Rate Method shall be used, if the
infiltration rate is known to be:

1. Less than 0.40 ACH and

2. Equal to or greater than 0.10 ACH

Infiltration rates greater than 0.60 ACH shall not be used. The
minimum required volume ofthe space varies with the number of
ACH and shall be determined per Table 3 or Equations 1 and 2.
Determine the minimum required volume for each appliance in
the space and add the volumes together to get the total minimum
required volume for the space.

9

Table 3 – Minimum Space Volumes for 100% Combustion, Ventilation, and Dilution from Indoors

OTHER THAN FAN---ASSISTED TOTAL

ACH

0.60 1,050 1,400 1,750 1,100 1,650 2,200 2,750 3,300 3,850

0.50 1,260 1,680 2,100 1,320 1,980 2,640 3,300 3,960 4,620

0.40 1,575 2,100 2,625 1,650 2,475 3,300 4,125 4,950 5,775

0.30 2,100 2,800 3,500 2,200 3,300 4,400 5,500 6,600 7,700

0.20 3,150 4,200 5,250 3,300 4,950 6,600 8,250 9,900 11,550

0.10 6,300 8,400 10,500 6,600 9,900 13,200 16,500 19,800 23,100

0.00 NP NP NP NP NP NP NP NP NP

NP = Not Permitted

Table 3--Minimum Space Volumes were determined by using
the following equations from the National Fuel Gas Code ANSI

Z223.1--2009/NFPA 54--2009, 9.3.2.2:

1. For other than fan--assisted appliances, such as a draft

hood--equipped water heater:

312AAV

Volume

2. For fan--assisted appliances such as this furnace:

Volume

If:

= combined input of all other than fan--assisted

I

other

= combined input of all fan--assisted appliances in

I

fan

ACH = air changes per hour (ACH shall not exceed 0.60.)

The following requirements apply to the Standard Method and
to the Known Air Infiltration Rate Method.

1. Adjoining rooms can be considered part of a space if:
a. There are no closeable doors between rooms.

b. Combining spaces on same floor level. Each opening

shall have free area of at least 1 in.
mm
in the space, but not less than 100 in.
opening shall commence within 12 in. (300 mm) of the
ceiling and the second opening shall commence within
12 in. (300 mm) of the floor. The minimum dimension
of air openings shall be at least 3 in. (80 mm). (See Fig.

8.)

c. Combining space on different floor levels. The volumes

of spaces on different floor levels shall be considered as
communicating spaces if connected by oneor moreper­manent openings in doors or floors having free area of
at least 2 in.
rating of all gas appliances.

2. An attic or crawlspace may be considered a space that

freely communicates with the outdoors provided there are
adequate permanent ventilation openings directly to out­doors having free area of at least 1--in.2/4,000 Btuh of
total input rating for all gas appliances in the space.

3. In spaces that use the Indoor Combustion Air Method, in-

filtration should be adequate to provide air for combus­tion, permanent ventilation and dilution of flue gases.

(1,000s BTUH GAS INPUT RATE)

30 40 50 44 66 88 110 132 154

SpaceVolume(ft.3)

3

21ft

=

Other

Fan

appliances in Btuh/hr

Btuh/hr

2

/kW) of the total input rating of all gas appliances

ACH

3

15ft

=

ACH

2

/1,000 Btuh (4,400 mm2/kW) of totalinput

I

other

1000 Btu/hr

I

fan

1000 Btu/hr

2

/1,000 Btuh (2,000

2

(0.06 m2). One

A04002

Combination of Indoor and Outdoor

1. Indoor openings shall comply with the Indoor Combus-

A04003

2. Outdoor openings shall be located as required in the Out-

3. Outdoor openings shall be sized as follows:

UPFLOW INSTALLATION
Bottom Return Air

These furnaces are shipped with bottom closure panel installed in
bottom return--air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel,
perform the following:

1. Tilt or raise furnace and remove 2 screws holding bottom

2. Rotate bottom filler panel downward to release holding

3. Remove bottom closure panel.

4. Reinstall bottom filler panel and screws.

Side Return Air

These furnaces are shipped with bottom closure panel installed in
bottom return--air opening. This panel MUST be in place when
only side return air is used.

FAN---ASSISTED TOTAL

(1,000s BTUH GAS INPUT RATE)

However, in buildings with unusually tight construction,
additional air MUST be provided using the methods de­scribed in the Outdoor Combustion Air Method section.
Unusually tight construction is defined as Construction
with:

a. Walls and ceilings exposed to the outdoors have a con-

tinuous, sealed vapor barrier. Openings are gasketed or

sealed and
b. Doors and openable windows are weatherstripped and
c. Other openings are caulked or sealed. These include

joints around window and door frames, between sole

plates and floors, between wall--ceiling joints, between

wall panels, at penetrations for plumbing, electrical and

gas lines, etc.

Air

tion Air Method below and,

door Combustion Air Method mentioned previously and,

a. Calculate the Ratio of all Indoor Space volume divided

by required volume for IndoorCombustion Air Meth-

od below.
b. Outdoor opening size reduction Factor is 1 minus the

Ratio in a. above.
c. Minimum size of Outdoor openings shall be the size re-

quiredinOutdoorCombustionAirMethodabovemul-

tiplied by reduction Factor in b. above. The minimum

dimension ofair openings shall be not lessthan 3 in. (80

mm).

INSTALLATION

Inlet

filler panel. (See Fig. 9.)

tabs.

Inlet

10

NOTE: Side return--air openings can be used in UPFLOW and
most HORIZONTAL configurations. Do not use side return--air
openings in DOWNFLOW configuration.

Bottom
Closure Panel

Bottom Filler Panel

A10273

Fig. 9 -- Removing Bottom Closure Panel

Leveling Legs (If Desir

ed)

In upflow position with side return inlet(s), leveling legs may be
used. (See Fig. 10.) Install field--supplied, 5/16 x 1--1/2 in. (8 x
38 mm) (max) corrosion--resistant machine bolts, washers and
nuts.

NOTE: Bottom closure must be used when leveling legs are
used. It may be necessary to remove and reinstall bottom closure
panel to install leveling legs. To remove bottom closure panel, see
item 1 in Bottom Return Air Inlet section in Step 1 above.

To install leveling legs:

1. Position furnace on its back. Locate and drill a hole in
each bottom corner of furnace. (See Fig. 10.)

2. For each leg, install nut on bolt and then install bolt and
nut in hole. (Install flat washer if desired.)

3. Install another nut on other side of furnace base. (Install
flat washer if desired.)

4. Adjust outside nut to provide desired height, and tighten
inside nut to secure arrangement.

5. Reinstall bottom closure panel if removed.

5/

16 ″

(8mm)

(8mm)

5/

16 ″

1 3 / 4 ″

(44mm)

3

1

/ 4 ″

(44mm)

(8mm)

5

/ 16 ″

(8mm)

5/

16 ″

1

(44mm)

3/

4 ″

3/

1

4 ″

A89014

(44mm)

Fig. 10 -- Leveling Legs

DOWNFLOW INSTALLA

TION

NOTE: For downflow applications, this furnace is approved for

use on combustible flooring when any one of the following 3
accessories are used:

S Special Base, KGASB
S Cased Coil Assembly Part No. CNPV, CNRV, CAP, and CAR
S Coil Box Part No. KCAKC

1. Determine application being installed from Table 4.

2. Construct hole in floor per Table 4 and Fig. 11.

3. Construct plenum to dimensions specified in Table 4 and
Fig. 11.

4. If downflow subbase, KGASB is used, install as shown in
Fig. 12. If Coil Assembly Part No. CNPV, CNRV, CAP,
CAR or Coil Box Part No. KCAKC is used, install as
shown in Fig. 13.

NOTE: It is recommended that the perforated supply--air duct
flanges be completely folded over or removed from furnace when
installing the furnace on a factory--supplied cased coil or coil box.
To remove the supply--air duct flange, use wide duct pliers or
hand seamers to bend flange back and forth until it breaks off. Be
careful of sharp edges. (See Fig. 14.)

Bottom Return Air

Inlet

These furnaces are shipped with bottom closure panel installed in
bottom return--air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel,
perform the following:

1. Tilt or raise furnace and remove 2 screws holding bottom
filler panel. (See Fig. 9.)

2. Rotate bottom filler panel downward to release holding
tabs.

3. Remove bottom closure panel.

4. Reinstall bottom filler panel and screws.

HORIZONTAL INSTALLA

TION

The furnace can be installed horizontally in an attic or crawl space
on either the left--hand (LH) or right--hand (RH) side. The furnace
can be hung from floor joists, rafters or trusses or installed on a
non--combustible platform, blocks, bricks or pad.

!

WARNING

FIRE, EXPLOSION, AND CARBON MONOXIDE
POISONING HAZARD

Failure to follow this warning could result in personal
injury, death, or property damage.

Do not install the furnace on its back or hang furnace with
control compartment facing downward. Safety control
operation will be adversely affected. Never connect
return--air ducts to the back of the furnace.

Suspended Furnace Support

The furnace may be supported under each end with threaded rod,
angle iron or metal plumber’s strap as shown. (See Fig. 15 and

16.) Secure angle iron to bottom of furnace as shown.
Heavy--gauge sheet metal straps (plumber’s straps) may be used
to suspend the furnace from each bottom corner. To prevent
screws from pulling out, use 2 #8 x 3/4--in. (19 mm) screw into
the side and 2 #8 x 3/4--in. (19 mm) screw in the bottom of the
furnace casing for each strap. (See Fig. 15 and 16.)

If the screws are attached to ONLY the furnace sides and not the
bottom, the straps must be vertical against the furnace sides and
not pull away from the furnace sides, so that the strap attachment
screws are not in tension (are loaded in shear) for reliable support.

312AAV

11

Platform Furnace

Support

Construct working platform at location where all required furnace
clearances are met. (See Fig. 2 and 17.) For furnaces with 1--in.
(25 mm) clearance requirement on side, set furnace on
non--combustible blocks, bricks or angle iron. For crawlspace
installations, if the furnace is not suspended from the floor joists,
the ground underneath furnace must be level and the furnace set
on blocks or bricks.

Roll--Out Pr

otection

Provide a minimum 17--3/4--in. x 22--in. (451 x 559 mm) piece of
sheet metal for flame roll--out protection in front of burner area
for furnaces closer than 12 inches (305 mm) above the
combustible deck or suspended furnaces closer than 12 inches
(305 mm) to joists. The sheet metal MUST extend underneath the
furnace casing by 1 in. (25 mm) with the door removed.

The bottom closure panel on furnaces of widths 17--1/2 in. (445
mm) and larger may be used for flame roll--out protection when
bottom of furnace is used for return air connection. See Fig. 17.
for proper orientation of roll--out shield.

Bottom Return Air

312AAV

Inlet

These furnaces are shipped with bottom closure panel installed in
bottom return--air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel,
perform the following:

1. Tilt or raise furnace and remove 2 screws holding bottom
filler panel. (See Fig. 9.)

2. Rotate bottom filler panel downward to release holding
tabs.

3. Remove bottom closure panel.

4. Reinstall bottom filler panel and screws.

Side Return Air

Inlet

These furnaces are shipped with bottom closure panel installed in
bottom return--air opening. This panel MUST be in place when
side return air inlet(s) are used without a bottom return air inlet.

FURNACE

(OR COIL CASING

WHEN USED)

COMBUSTIBLE

FLOORING

DOWNFLOW

SUBBASE

SHEET METAL

PLENUM

FLOOR

OPENING

Fig. 12 -- Furnace, Plenum, and Subbase installed on a

Combustible Floor

FURNACE

APPROVED

COIL ASSEMBLY

OR

COIL BOX

A96285

A

PLENUM

OPENING

B

OPENING

D

FLOOR

C

Fig. 11 -- Floor and Plenum Opening Dimensions

A96283

COMBUSTIBLE

FLOORING

SHEET METAL

PLENUM

FLOOR

OPENING

A08556

Fig. 13 -- Furnace, Plenum, and Coil Assembly or Coil Box

Installed on a Combustible Floor

12

Table 4 – Opening dimensions -- In. (mm)

FURNACE

CASING

WIDTH

14–3/16

(376)

17–1/2

(445)

21

(533)

24--- 1/2

(622)

APPLICATION

Upflow Applications on Combustible or Noncombustible Floor-

ing (KGASB subbase not required)

Downflow Applications on Noncombustible Flooring (KGASB

subbase not required)

Downflow applications on combustible flooring (KGASB sub-

base required)

Downflow Applications on Combustible Flooring with CNPV,

CNRV, CAR, or CAP Coil Assembly or KCAKC coil box

(KGASB subbase not required)

Upflow Applications on Combustible or Noncombustible Floor-

ing (KGASB subbase not required)

Downflow Applications on Noncombustible Flooring (KGASB

subbase not required)

Downflow applications on combustible flooring (KGASB sub-

base required)

Downflow Applications on Combustible Flooring with CNPV,

CNRV, CAR, or CAP Coil Assembly or KCAKC coil box

(KGASB subbase not required)

Upflow Applications on Combustible or Noncombustible Floor-

ing (KGASB subbase not required)

Downflow Applications on Noncombustible Flooring (KGASB

subbase not required)

Downflow applications on combustible flooring (KGASB sub-

base required)

Downflow Applications on Combustible Flooring with CNPV,

CNRV, CAR, or CAP Coil Assembly or KCAKC coil box

(KGASB subbase not required)

Upflow Applications on Combustible or Noncombustible Floor-

ing (KGASB subbase not required)

Downflow Applications on Noncombustible Flooring (KGASB

subbase not required)

Downflow applications on Combustible flooring (KGASB sub-

base required)

Downflow Applications on Combustible Flooring with CNPV,

CNRV, CAR, or CAP Coil Assembly or KCAKC coil box

(KGASB subbase not required)

PLENUM OPENING FLOOR OPENING

A B C D

12--- 11/16

(322)

12--- 9/16

(319)

11--- 13/16

(284)

12--- 5/16

(319)

16

(406)

15--- 7/8

(403)

15--- 1/8

(384)

15--- 1/2

(394)

19--- 1/2

(495)

19--- 3/8

(492)

18--- 5/8

(473)

19

(483)

23

(584)

22--- 7/8

(581)

22--- 1/8

(562)

22--- 1/2

(572)

21--- 5/8

(549)

19

(483)

19

(483)

19

(483)

21--- 5/8

(549)

19

(483)

19

(483)

19

(483)

21--- 5/8

(549)

19

(483)

19

(483)

19

(483)

21--- 1/8

(537)

19

(483)

19

(483)

19

(483)

13--- 5/16

(338)

13--- 3/16

(335)

13--- 7/16

(341)

13--- 5/16

(338)

16--- 5/8

(422)

16--- 1/2

(419)

16--- 3/4

(425)

16--- 1/2

(419)

20--- 1/8

(511)

20

(508)

20--- 1/4

(514)

20

(508)

23--- 5/8

(600)

23--- 1/2

(597)

23--- 3/4

(603)

23--- 1/2

(597)

22--- 1/4

(565)

19--- 5/8

(498)

20--- 5/8

(600)

20

(508)

22--- 1/4

(565)

19--- 5/8

(498)

20--- 5/8

(600)

20

(508)

22--- 1/4

(565)

19--- 5/8

(498)

20--- 5/8

(600)

20

(508)

22--- 1/4

(565)

19--- 5/8

(498)

20--- 5/8

(600)

20

(508)

312AAV

UPFLOW DOWNFLOW HORIZONTAL

120°

MIN

90°

YES

YES

NO

YES

120°

MIN

YES

Fig. 14 -- Duct Flanges

13

NO

120°

MIN

90°

YES

YES

NO

A02020

1

/

4 " (6mm) THREADED ROD

4 REQ.

OUTER DOOR
A S SEMBLY

SECURE ANGLE

312AAV

8" (203mm)
FOR DOOR REMOVAL

MIN

1” (25mm) SQUARE, 1-1/4”x1-1/4”x1/8” (32x32x3mm)
ANGLE IRON OR UNI-STRUT MAY BE USED

IRON TO BOTTOM
OF FURNACE WITH

3

/4" (19mm) SCREWS

3 #8 x
TYPICAL FOR 2 SUPPORTS

(2) HEX NUTS, (2) WASHERS & (2) LOCK WASHERS
REQ. PER ROD

Fig. 15 -- Horizontal Unit Suspension

METHOD 2
USE (4) #8 x 3/4 (19 mm) SHEET
METAL SCREWS FOR EACH
STRAP. THE STRAPS
SHOULD BE VERTICAL
AGAINST THE FURNACE
SIDES AND NOT PULL AWAY
FROM THE FURNACE
SIDES.

A10130

METHOD 1
FOLD ALL STRAPS UNDER
FURNACE AND SECURE WTH
(4) #8 x 3/4 (19 mm) SHEET METAL SCREWS
(2 SCREWS IN SIDE AND 2 SCREWS
IN BOTTOM).

Fig. 16 -- Horizontal Suspension with Straps

14

A10131

LINE CONT A CT ONL Y PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE T OP AND TW O SIDES OF THE FURNA CE
JA CKET AND BUILDING JOISTS ,
STUDS , OR FRAMING.

EQUIPMENT MANU AL

SHUT -OFF GAS VA LV E

SEDIMENT

TRAP

UNION

SHEET
MET AL

GAS
ENTR Y

17 3 / 4 ″

22

(559mm)

″

(451mm)

6 ″

M IN

TYPE-B
VENT

(152mm)

*

Fig. 17 -- Typical Attic Installation

17 3 / 4 ″
4 3 / 4 ″
1 ″

(25mm)

EXTEND OUT 12 ″
FR OM FA CE OF DOOR

30-IN . (762mm)
MIN WORK AREA

(451mm)

(121mm)

* WHEN USED W ITH
SINGLE W ALL VEN T
CONNECTIONS

OVERALL

UNDER DOOR

UNDER FURNACE

(305mm)

312AAV

A10164

Not all horizontal furnaces are approved for side return air
connections. (See Fig. 20.)

FILTER

ARRANGEMENT

!

WARNING

CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in personal
injury, or death.

Never operate a furnace without a filter or with filter access
door removed.

There are no provisions for an internal filter rack in these
furnaces. A field--supplied, accessory external filter rack is
required.

Refer to the instructions supplied with the external filter rack for
assembly and installation options.

DUCTS

AIR
General Requir

ements

The duct system should be designed and sized according to
accepted national standards such as those published by: Air
Conditioning Contractors Association (ACCA), Sheet Metal and
Air Conditioning Contractors National Association (SMACNA)
or American Society of Heating, Refrigerating and Air
Conditioning Engineers (ASHRAE) or consult The Air Systems
Design Guidelines reference tables available from your local
distributor. The duct system should be sized to handle the
required system design CFM at the design external static pressure.
The furnace airflow rates are provided in Table 5--Air Delivery
CFM (With Filter).

When a furnace is installed so that the supply ducts carry air
circulated by the furnace to areas outside the space containing the
furnace, the return air shall also be handled by duct(s) sealed to
the furnace casing and terminating outside the space containing
the furnace.

Secure ductwork with proper fasteners for type of ductwork used.
Seal supply-- and return--duct connections to furnace with code
approved tape or duct sealer.

NOTE: Flexible connections should be used between ductwork
and furnace to prevent transmission of vibration.

Ductwork passing through unconditioned space should be
insulated to enhance system performance. When air conditioning
is used, a vapor barrier is recommended.

Maintain a 1--in. (25 mm) clearance from combustible materials
to supply air ductwork for a distance of 36 in. (914 mm)
horizontally from the furnace. See NFPA 90B or local code for
further requirements.

Ductwork Acoustical Tr

eatment

NOTE: Metal duct systems that do not have a 90_ elbow and 10

ft. (3 M) of main duct to the first branch take--off may require
internal acoustical lining. As an alternative, fibrous ductwork may
be used if constructed and installed in accordance with the latest
edition of SMACNA construction standard on fibrous glass
ducts. Both acoustical lining and fibrous ductwork shall comply
with NFPA 90B as tested by UL Standard 181 for Class 1 Rigid
air ducts.

Supply Air

Connections

For a furnace not equipped with a cooling coil, the outlet duct
shall be provided with a removable access panel. This opening
shall be accessible when the furnace is installed and shall be of
such a size that the heat exchanger can be viewed for possible
openings using light assistance or a probe can be inserted for
sampling the air stream. The cover attachment shall prevent leaks.

Upflow and Horizontal

Furnaces

Connect supply--air duct to flanges on furnace supply--air outlet.
Bend flange upward to 90_ with wide duct pliers. (See Fig. 14.)
The supply--air duct must be connected to ONLY the furnace
supply--outlet--air duct flanges or air conditioning coil casing
(when used). DO NOT cut main furnace casing side to attach
supply air duct, humidifier, or other accessories. All accessories
MUST be connected to duct external to furnace main casing.

NOTE: For horizontal applications, the top--most flange may be
bent past 90_ to allow the evaporator coil to hang on the flange
temporarily while the remaining attachment and sealing of the
coil are performed.

15

Table 5 – Air Delivery -- CFM (With Filter)*

FURNACE

SIZE

045--- 08 /

024045

045--- 12/

036045

070--- 081 /

024070

070--- 12/

036070

312AAV

070--- 16/

048070

090--- 14/

042090

090--- 16/

048090

090--- 20/

060090

110--- 12/

036110

110--- 16/

048110

110--- 22/

066110

*A filter is r equired for each return --- air inlet. Airflow performance included 3/4 - --in. (19 mm) washable filter media such as contained in factory ---authorized ac­cessory filter rack. To determine airflow performance without this filter, assume an additional 0.1 In. W.C. available external static pressure.

------ Indicates unstable operating conditions.

RETURN---AIR

INLET

Bottom or

Side(s)

Bottom or

Side(s)

Bottom or

Side(s)

Bottom or

Side(s)

Bottom or

Side(s)

Bottom or

Side(s)

Bottom or

Side(s)

Bottom Only

Both Side or 1
Side & Bottom

1Side Only

Bottom or

Side(s)

Bottom or

Side(s)

Bottom Only

Bottom Sides or
1 Side & Bottom

1Side Only

SPEED

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

Medium

M e d --- L o w

Low

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

Medium

M e d --- L o w

Low

High

M e d --- H i g h

Medium

M e d --- L o w

Low

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

Medium

M e d --- L o w

Low

High

M e d --- H i g h

Medium

M e d --- L o w

Low

High

M e d --- H i g h

Medium

M e d --- L o w

Low

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

Medium

M e d --- L o w

Low

High

M e d --- H i g h

Medium

M e d --- L o w

Low

High

M e d --- H i g h

High

M e d --- H i g h

Medium

M e d --- L o w

Low

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1120

930
820

725
1465
1295
1150
1030

860
1140

915

795

690
1440
1180
1015

885

695
1840

1610
1460
1260
1065

1650
1515
1385
1205
2060
1710
1470
1260
1030

2380
2185
1905
1595
1340

2485
2175
1845
1540
1280

2420
2160
1850
1530
1290

1625
1510
1360
1195
2055
1750
1545
1300
1050

2530
2225
1895
1565
1320

--- ---

2205
2485

2155
1830
1520
1275

1075

890
785

690
1400
1260
1120
1010

835
1105

885

770

665
1400
1165
1020

885

700
1790

1575
1430
1240
1040

1600
1485
1360
1180
2000
1695
1475
1365
1025

2295
2115
1865
1565
1310

2415
2130
1815
1515
1250

2345
2110
1815
1490
1250

1575
1470
1335
1180
1990
1725
1525
1290
1045

2460
2190
1885
1555
1295

--- ---

2175
2430

2135
1830
1505
1260

EXTERNAL STATIC PRESSURE (IN. W.C.)

1020

850
750

655
1325
1210
1085

980

810
1055

855

740

630
1355
1150
1010

880

700
1730

1535
1400
1215
1015

1535
1440
1320
1160
1930
1665
1450
1245
1020

2205
2045
1815
1530
1280

2330
2070
1770
1475
1220

2265
2045
1765
1455
1220

1515
1415
1295
1155
1910
1670
1490
1275
1015

2380
2135
1865
1535
1265

2415
2120

2360
2100
1810
1490
1240

960
805
700

605
1250
1155
1040

945

780
1010

825

700

590
1300
1125

990

865

690
1670

1485
1360
1180

985
1465

1380
1260
1120
1835
1585
1390
1225

990
2105

1960
1740
1485
1225

2230
2000
1720
1435
1190

2165
1960
1710
1420
1190

1445
1355
1250
1115
1815
1605
1445
1235

975
2285

2075
1820
1505
1235

2330
2065

2270
2040
1780
1470
1210

895
750
650

555
1175
1090

985

895

745

955

785

655

550
1240
1085

965

845

670
1605

1435
1315
1145

955
1385

1300
1195
1065
1755
1480
1335
1165

940
2005

1875
1670
1430
1170

2135
1930
1655
1385

115
2070

1885
1635
1375

115
1355

1285
1180
1065
1695
1515
1355
1165

935
2200

1995
1770
1465
1205

2235
1975

2175
1970
1730
1430
1180

815
680
585

495
1085
1015

920

835

700

885

725

600

475
1170
1030

925

815

640
1530

1370
1260

110

915
1285

1220
1120
1005
1620
1390
1230
1090

890
1900

1770
1590
1355
1120

2030
1840
1580
1335
1105

1960
1790
1560
1320
1110

1260
1185
1100

980
1575
1400
1260
1085

880
2085

1910
1700
1410
1160

2125
1900

2070
1885
1665
1385
1135

720
600
505
405
980
930
835
765
635

815
655
510
415

1090

970
875
770
600

1450
1305
1205
1040

875

1175
1115
1025

925
1490
1245
1120

995

810
1775

1655
1490
1275
1040

1920
1740
1500
1270
1035

1850
1695
1480
1250
1040

1165
1070

985

860
1425
1255
1135
1005

815
1970

1805
1610
1350
1105

1995
1790

1950
1790
1595
1330
1090

605
500
400
305
860
830
740
685
555

715
530
420
340

1000

890
800
700
540

1370
1230
1130

985
825

1055

990
915

810
1315
1110
1005

880

720
1650

1535
1390
1160

955
1790

1620
1395
1175

945
1720

1570
1380
1160

950

990

890

810

740
1230
1120
1020

895

715
1835

1695
1520
1265
1035

1860
1685

1825
1680
1505
1250
1025

455
345
235

--- --­725
700
620
570
445
545
420
325
245
890
785
700
605
460

1275
1145
1055

915
765

895
830
710
630

1115

955
855
750
615

1510
1400
1245
1055

850

1645
1495
1270
1045

845

1570
1445
1250
1055

835
785

725
670
605

1090

975
880
750
610

1695
1565
1410
1175

950

1735
1580

1685
1560
1395
1165

930

340
195

--- ---

--- --­560
545
510
345
260
390
280

--- ---

--- --­745
645
560
475
345

1170
1055

965
835
695

645
600
565
510
910
775
690
600
500

1335
1240
1110

920
750

1485
1345
1090

915
745

1420
1305
1110

905
740

595
530
475
410
910
785
750
620
515

1545
1430
1290
1050

870

1605
1460

1535
1420
1275
1055

840

16

Table 5 -- Air Delivery -- CFM (With Filter)* (Cont.)

FURNACE

SIZE

135--- 16/

048135

135--- 22/

066135

155--- 20/

060155

*A filter is r equired for each return --- air inlet. Airflow performance included 3/4 - --in. (19 mm) washable filter media such as contained in factory ---authorized ac­cessory filter rack. To determine airflow performance without this filter, assume an additional 0.1 In. W.C. available external static pressure.

------ Indicates unstable operating conditions.

RETURN---AIR

INLET

Bottom

or

Side(s)

Bottom

Only

Bottom Sides

or

1 Side & Bottom

1SideOnly

Bottom Only

Both Sides O r 1

Side & Bottom

1SideOnly

SPEED

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

M e d --- L o w

Low

High

M e d --- H i g h

High

M e d --- H i g h

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

2090
1790
1545
1325
2485
2195
1880
1640

--- --­2180
1880
1640

2320
2125
1845
1640

2465
2115
1800
1570

--- --­2155

--- --­2140

2010
1755
1525
1320
2400
2150
1850
1635

--- --­2145
1850
1635

2250
2065
1825
1620

2430
2105
1790
1565

--- --­2135

--- --­2095

Downflow Furnaces

EXTERNAL STATIC PRESSURE (IN. W.C.)

1930
1705
1500
1295
2310
2090
1820
1615

2385
2060
1820
1615

2155
1995
1765
1580

2375
2075
1770
1550

2375
2095

2260
2040

1835
1640
1450
1265
2215
2000
1780
1585

2305
2010
1780
1585

2055
1910
1710
1540

2305
2030
1735
1525

2285
2040

2180
1975

GAS

1710
1550
1380
1210
2110
1920
1715
1530

2195
1945
1715
1530

1970
1815
1650
1485

2230
1980
1695
1495

2200
1975

2085
1890

PIPING

1590
1465
1315
1150
2000
1825
1635
1465

2085
1865
1635
1465

1855
1710
1570
1410

2110
1910
1640
1445

2105
1895

1975
1810

1470
1360
1215

995
1880
1720

1540
1370

1960
1765
1540
1370

1725
1610
1475
1330

2000
1830
1570
1370

1995
1790

1865
1705

1335
1210
1005

865
1725
1565

1415
1255

1825
1660
1415
1255

1600
1490
1370
1220

1865
1725
1465
1270

1870
1685

1740
1595

1025

945
855

745
1535
1405

1290
1150

1670
1515
1290
1150

1450
1340
1240
1080

1725
1590
1345
1175

1730
1550

1605
1480

835
785
670

540
1355
1255

1160
1040

1465
1325
1160
1040

1280
1175
1100

960
1545

1425
1225
1070

1570
1400

1455
1325

Connect supply--air duct to supply--air outlet on furnace. Bend
flange inward past 90_ with wide duct pliers. (See Fig. 14.) The
supply--air duct must be connected to ONLY the furnace
supplyoutlet or air conditioning coil casing (when used). When
installed on combustible material, supply--air duct must be
connected to ONLY the factory--approved accessory subbase, or
a factory approved air conditioning coil casing. DO NOT cut
main furnace casing to attach supply side air duct, humidifier, or
other accessories. All accessories MUST be connected to duct
external to furnace casing.

Return Air

Connections

FIRE OR EXPLOSION HAZARD

Failure to follow this warning could result in personal
injury, death, and/or property damage.

Never purge a gas line into a combustion chamber. Never
test for gas leaks with an open flame. Use a commercially
available soap solution made specifically for the detection
of leaks to check all connections.

!

WARNING

312AAV

!

WARNING

FIRE HAZARD

Failure to follow this warning could cause personal injury,
death and/or property damage.

Never connect return--air ducts to the back of the furnace.
Follow instructions below.

Downflow Furnaces

The return--air duct must be connected to return--air opening
(bottom inlet) as shown in Fig. 1. DO NOT cut into casing sides
(left or right). Side opening is permitted for only upflow and most
horizontal furnaces. Bypass humidifier connections should be
made at ductwork or coil casing sides exterior to furnace. (See
Fig. 19.)

Upflow and Horizontal

Furnaces

The return--air duct must be connected to bottom, sides (left or
right), or a combination of bottom and side(s) of main furnace
casing as shown in Fig. 1. Bypass humidifier may be attached
into unused return air side of the furnace casing. (See Fig. 18 and

20.) Not all horizontal furnaces are approved for side return air
connections. (See Fig. 20.)

!

WARNING

FIRE OR EXPLOSION HAZARD

Failure to follow this warning could result in personal
injury, death, and/or property damage.

Use proper length of pipe to avoid stress on gas control
manifold and a gas leak.

!

WARNING

FIRE OR EXPLOSION HAZARD

Failure to protect gas valve inlet from water and debris
could result in death, personal injury and/or property
damage.

Gas valve inlet and/or inlet pipe must remain capped until
gas supply line is permanently installed to protect the valve
from moisture and debris. Also, install a sediment trap in the
gas supply piping at the inlet to the gas valve.

17

A02075

312AAV

Fig. 18 -- Upflow Return Air Configurations and Restrictions

A02163

Fig. 19 -- Downflow Return Air Configurations and Restrictions

Fig. 20 -- Horizontal Return Air Configurations and Restrictions

18

A02162

Gas piping must be installed in accordance with national and
local codes. Refer to current edition of NFGC in the U.S.

Table 6 – Maximum Capacity of Pipe

NOMINAL

IRON PIPE

SIZE

IN. (MM)

1/2 (12.7)

3/4 (19.0)

1( 25.4)

1-1/4
(31.8)

1-1/2
(38.1)

* Cubic ft. of natural gas per hr for gas pressures of 0.5 psig (14 ---In. W.C.)

or l ess and a pressure drop of 0.5 --- In. W.C. (based on a 0.60 specific
gravity gas). Ref: Table 6 and NFPA54/ANSI Z223.1---2009.

INTERNAL

DIA.

IN. (MM)

0.622
(158)

0.824
(20.9)

1.049
(26.6)

1.380
(35.0)

1.610
(40.9)

LENGTH OF PIPE --- FT. (M)

10

(3.0)20(6.0)30(9.1)40(12.1)50(15.2)

175 120 97 82 73

360 250 200 170 151

680 465 375 320 285

1400 950 770 660 580

2100 1460 1180 990 900

An accessible manual equipment shutoff valve MUST be
installed external to furnace casing and within 6 ft. of furnace. A
1/8--in. (3 mm) NPT plugged tapping, accessible for test gauge
connection, MUST be installed immediately upstream of gas
supply connection to furnace and downstream of manual
equipment shutoff valve.

NOTE: The furnace gas control valve inlet pressure tap
connection is suitable to use as test gauge connection providing
test pressure DOES NOT exceed maximum 0.5 psig (14--In.
W.C.) stated on gas control valve. (See Fig. 48.) Some
installations require gas entry on right side of furnace (as viewed
in upflow). (See Fig. 21.)

Installations must be made in accordance with all authorities
having jurisdiction. If possible, the gas supply line should be a
separate line running directly from meter to furnace.

NOTE: In the state of Massachusetts:

1. Gas supply connections MUST be performed by a li­censed plumber or gas fitter.

2. When flexible connectors are used, the maximum length
shall not exceed 36 inches (915 mm).

3. When lever handle type manual equipment shutoff valves
are used, they shall be T--handle valves.

4. The use of copper tubing for gas piping is NOT approved
by the state of Massachusetts.

Refer to Table 6 for recommended gas pipe sizing. Risers must be
used to connect to furnace and to meter. Support all gas piping
with appropriate straps, hangers, etc. Use a minimum of 1 hanger
every 6 ft. (1.8 M). Joint compound (pipe dope) should be
applied sparingly and only to male threads of joints. Pipe dope
must be resistant to the action of propane gas.

!

WARNING

FIRE OR EXPLOSION HAZARD

Failure to follow this warning could result in personal
injury, death, and/or property damage.

If local codes allow the use of a flexible gas appliance
connector, always use a new listed connector. Do not use a
connector which has previously served another gas
appliance. Black iron pipe shall be installed at the furnace
gas control valve and extend a minimum of 2 in. (51 mm)
outside the furnace.

2” (51mm)

Street Elbow

A08551

Fig. 21 -- Burner and Manifold

Install a sediment trap in riser leading to furnace as shown in Fig.

22. Connect acapped nipple into lower end of tee. Capped nipple
should extend below level of furnace gas controls. Place a ground
joint union between furnace gas control valve manifold and
exterior manual equipment gas shutoff valve.

GAS
SUPPLY

MANUAL
SHUTOFF
VALV E
(REQUIRED)

SEDIMENT
TRAP

UNION

A02035

Fig. 22 -- Typical Gas Pipe Arrangement

312AAV

!

CAUTION

FURNACE DAMAGE HAZARD

Failure to follow this caution may result in furnace damage.
Connect gas pipe to furnace using a backup wrench to

avoid damaging gas controls and burner misalignment.

19

FIVE

WIRE

THREE-WIRE

BLK

WHT

115-VOLT FIELD-

SUPPLIED

FUSED

DISCONNECT

GND

BLK

WHT

JUNCTION
BOX

312AAV

HEATING-

ONLY

CONTROL

BOX

FURNACE

W2

COM

W/W1

Y/Y2

R

G

24-VOLT

TERMINAL

BLOCK

A 1/8--in. (3 mm) NPT plugged tapping, accessible for test gauge
connection, MUST be installed immediately upstream of gas
supply connection to furnace and downstream of manual
equipment shutoff valve.

Piping should be pressure and leak tested in accordance with
NFGC in the United States, local, and national plumbing and gas
codes before the furnace has been connected. After all
connections have been made, purge lines and check for leakage at
furnace prior to operating furnace.

If pressure exceeds 0.5 psig (14--In. W.C.), gas supply pipe must
be disconnected from furnace and capped before and during
supply pipe pressure test. If test pressure is equal to or less than

0.5 psig (14--In. W.C.), turn off electric shutoff switch located on
furnace gas control valve and accessible manual equipment
shutoff valve before and during supply pipe pressure test. After
all connections have been made, purge lines and check for
leakage at furnace prior to operating furnace.

The gas supply pressure shall be within the maximum and
minimum inlet supply pressures marked on the rating plate with
the furnace burners ON and OFF.

ELECTRICAL

CONNECTIONS

!

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal
injury or death.

Blower access panel door switch opens 115--v power to
control. No component operation can occur. Do not bypass
or close switch with panel removed.

See Fig. 23 for field wiring diagram showing typical field 115--v
wiring. Check all factory and field electrical connections for
tightness.

Field--supplied wiring shall conform with the limitations of 63_F
(33_C) rise.

NOTE 2

WCY RG

NOTE 1

NOTES: 1.

Connect Y/Y2-terminal as shown for proper operation.
Some thermostats require a "C" terminal connection as shown.

2.
If any of the original wire, as supplied, must be replaced, use

3.
same type or equivalent wire.

1-STAGE
THERMOSTAT
TERMINALS

Fig. 23 -- Field Wiring Diagram

ELECTRICAL SHOCK AND FIRE HAZARD

Failure to follow this warning could result in personal
injury, death, or property damage.

The cabinet MUST have an uninterrupted or unbroken
ground according to NEC ANSI/NFPA 70--2008 or local
codes to minimize personal injury if an electrical fault
should occur. This may consist of electrical wire, conduit
approved for electrical ground or a listed, grounded power
cord (where permitted by local code) when installed in
accordance with existing electrical codes. Refer to the
power cord manufacturer’s ratings for proper wire gauge.
Do not use gas piping as an electrical ground.

FURNACE MAY NOT OPERATE HAZARD

Failure to follow this caution may result in intermittent
furnace operation.

Furnace control must be grounded for proper operation or
else control will lock out. Control must remain grounded
through green/yellow wire routed to gas valve and manifold
bracket screw.

115 --V WIRING

Verify that the voltage, frequency, and phase correspond to that
specified on unit rating plate. Also, check to be sure that service
provided by utility is sufficient to handle load imposed by this
equipment. Refer to rating plate or Table 7 for equipment
electrical specifications.

FIELD 24-VOLT WIRING
FIELD 115-, 208/230-, 460-VOLT WIRING
FACTORY 24-VOLT WIRING
FACTORY 115-VOLT WIRING

FIELD-SUPPLIED

FUSED DISCONNECT

208/230- OR
460-VOLT
THREE
PHASE

208/230­VOLT
SINGLE
PHASE

CONDENSING

UNIT

!

WARNING

!

CAUTION

GND

A95236

20

Table 7 – Electrical Data

Factory
Installed

Alternate
Location

FURNACE

SIZE

045--- 08/024045 1 1 5 --- 6 0 --- 1 127 104 5.3 7.42 49 (14.9) 15 14
045--- 12/036045 1 1 5 --- 6 0 --- 1 127 104 7.1 9.67 38 (11.5) 15 14
070--- 08/024070 1 1 5 --- 6 0 --- 1 127 104 5.2 7.22 51 (15.5) 15 14
070--- 12/036070 1 1 5 --- 6 0 --- 1 127 104 7.3 9.90 37 (11.2) 15 14
070--- 16/048070 1 1 5 --- 6 0 --- 1 127 104 10.1 13.42 27 (8.2) 15 14
090--- 14/042090 1 1 5 --- 6 0 --- 1 127 104 8.2 10.84 34 (10.3) 15 14
090--- 16/048090 1 1 5 --- 6 0 --- 1 127 104 9.9 13.0 28 (8.5) 15 14
090--- 20/060090 1 1 5 --- 6 0 --- 1 127 104 12.9 16.70 34 (10.3) 20 12
110--- 12/036110 1 1 5 --- 6 0 --- 1 127 104 8.2 10.76 34 (10.3) 15 14
110--- 16/048110 1 1 5 --- 6 0 --- 1 127 104 10.1 13.19 28 (8.5) 15 14
110--- 22/066110 1 1 5 --- 6 0 --- 1 127 104 13.7 17.60 32 (9.7) 20 12
135--- 16/048135 1 1 5 --- 6 0 --- 1 127 104 10.2 13.28 27 (8.2) 15 14
135--- 22/066135 1 1 5 --- 6 0 --- 1 127 104 14.5 18.61 30 (9.1) 20 12
155--- 20/060155 1 1 5 --- 6 0 --- 1 127 104 15.0 19.34 29 (8.8) 20 12

* Permissible limits of the voltage range at which the unit operates satisfactorily.
# Unit ampacity = 125% of largest operating component’s ful l load amps plus 100% of all other potential operating components (EAC, humidifier,

etc.) full load amps.

{ Time --- delay type is recommended.
} Length shown is as measured 1 way along wire path between unit and service panel for maximum 2% voltage drop.

V O L T S --­H E R T Z ---

PHASE

U.S. Installations: Make all electrical connections in accordance
with National Electrical Code (NEC) ANSI/NFPA 70--2008 and

OPERATING VOLTAGE

RANGE

MAX* MIN.*

MAX

UNIT

AMPS

UNIT

AMPACITY#

5. Route J--Box wires within furnace away from sharp edges,
rotating parts, and hot surfaces.

MAXIMUM

WIRE

LENGTH

FT. (M)‡

MAXIMUM

FUSE OR
CKT BKR

AMPS†

MINIMUM

any local codes or ordinances that might apply.

Factory

!

WARNING

Installed

WIRE

GAUGE

312AAV

FIRE HAZARD

Failure to follow this warning could result in personal
injury, death, or property damage.

Do not connect aluminum wire between disconnect switch
and furnace. Use only copper wire.

Use a separate branch electrical circuit with a properly sized fuse
or circuit breaker for this furnace. See Table 7 for wire size and
fuse specifications. A readily accessible means of electrical
disconnect must be located within sight of the furnace.

NOTE: Proper polarity must be maintained for 115--v wiring. If
polarity is incorrect, control LED status indicator light will flash
rapidly and furnace will NOT operate.

J--BOX RELOCA

TION

NOTE: If factory location of J--Box is acceptable, go to next

section (ELECTRICAL CONNECTION TO J--BOX).
NOTE: On 14” wide casing models, the J--Box shall not be

relocated to other side of furnace casing when the vent pipe is
routed within the casing.

1. Remove and save two screws holding J--Box. (See Fig. 24
.)

NOTE: The J--Box cover need not be removed from the J--Box
in order to move the J--Box. Do NOT remove green ground
screw inside J--Box.

2. Cut wire tie on loop in furnace wires attached to J--Box.

3. Move J--Box to desired location.

4. Fasten J--Box to casing with the two screws removed in
Step 1.

Alternate
Location

Fig. 24 -- Relocating J--Box

ELECTRICAL CONNECTION TO

J--BOX

6. Reinstall cover to J--Box. Do not pinch wires between
cover and bracket.

Electrical Box on Furnace Casing Side. See Fig.

!

WARNING

25.

FIRE OR ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal
injury, death, or property damage.

If field--supplied manual disconnect switch is to be mounted
on furnace casing side, select a location where a drill or
fastener cannot damage electrical or gas components.

A10291

21

312AAV

A10141

Fig. 25 -- Field--Supplied Electrical Box on Furnace Casing

1. Select and remove a hole knockout in the casing where the
electrical box is to be installed.

NOTE: Check that duct on side of furnace will not interfere with
installed electrical box.

2. Remove the desired electrical box hole knockout and posi­tion the hole in the electrical box over the hole in the fur­nace casing.

3. Fasten the electrical box to casing by driving two field-­supplied screws from inside electrical box into casing
steel.

4. Remove and save two screws holding J--Box. (See Fig.

24.)

5. Pull furnace power wires out of 1/2--inch (12 mm) diamet­er hole in J--Box. Do not loosen wires from strain--relief
wire--tie on outside of J--Box.

6. Route furnace power wires through holes in casing and
electrical box and into electrical box.

7. Pull field power wires into electrical box.

8. Remove cover from furnace J--Box.

9. Route field ground wire through holes in electrical box
and casing, and into furnace J--Box.

10. Reattach furnace J--Box to furnace casing with screws re­movedinStep4.

11. Secure field ground wire to J--Box green ground screw.

12. Complete electrical box wiring and installation. Connect
line voltage leads as shown in Fig. 23. Use best practices
(NEC in U.S. for wire bushings, strain relief, etc.

13. Reinstall cover to J--Box. Do not pinch wires between
cover and bracket.

POWER CORD INSTALLATION IN FURNACE

J--BOX

NOTE: Power cords must be able to handle the electrical

requirements listed in Table 7. Refer to power cord
manufacturer’s listings.

1. Remove cover from J--Box.

2. Route listed power cord through 7/8--inch (22 mm) dia­meter hole in J--Box.

3. Secure power cord to J--Box bracket with a strain relief
bushing or a connector approved for the type of cord used.

4. Secure field ground wire to green ground screw on J--Box
bracket.

5. Connect line voltage leads as shown in Fig. 23.

6. Reinstall cover to J--Box. Do not pinch wires between
cover and bracket.

BX. CABLE INSTALLATION IN FURNACE

J--BOX

1. Remove cover from J--Box.

2. Route BX cable into 7/8--inch (22 mm) diameter hole in
J--Box.

3. Secure BX cable to J--Box bracket with connectors ap­proved for the type of cable used.

4. Secure field ground wire to green ground screw on J--Box
bracket.

5. Connect line voltage leads as shown in Fig. 23.

6. Reinstall cover to J--Box. Do not pinch wires between
cover and bracket.

24--V

WIRING

Make field 24--v connections at the 24--v terminal strip. (See Fig.

33.) Connect terminal Y/Y2 as shown in Fig. 26--32 for proper
cooling operation. Use only AWG No. 18, color--coded, copper
thermostat wire.

The 24--v circuit contains an automotive--type, 3--amp. fuse
located on the control. Any direct shorts during installation,
service, or maintenance could cause this fuse to blow. If fuse
replacement is required, use ONLY a 3--amp. fuse of identical
size.

22

312AAV

See notes 2, 5, 8, 10, 11 and 12
on the page following these figures

Fig. 26 -- Two--Stage Furnace with Two--Speed Air

Conditioner

A03179

See notes 1, 2, 3, 4, 6, 8, 9, 10, 12, 13 and 15
on the page following these figures

A03178

Fig. 28 -- Two--Stage Furnace with Two--Speed Heat Pump

(Dual Fuel)

See notes 1, 2, 4, 6, 7, 9, 10, 11, and 15
on the page following these figures

A03180

Fig. 27 -- Two--Stage Furnace with Single--Speed Heat Pump

(Dual Fuel)

See notes 1, 2, 4, 11, 14, 15, and 16
on the page following these figures

Fig. 29 -- Dual Fuel Thermostat with Two--Stage Furnace

and Single--Speed Heat Pump

23

A03181

7

312AAV

See notes 1, 2, 3, 4, 12, 13, 14, 15, and 17
on the page following these figures

Fig. 30 -- Dual Fuel Thermostat with Two--Stage Furnace

and Two--Speed Heat Pump

Fig. 32 -- Single--Stage Thermostat with Two--Stage Furnace and Two--Speed Air Conditioner

A03182

Fig. 31 -- Two--Stage Thermostat with Two--Stage Furnace

See notes 1 and 2 on the page
following these figures

See notes 2, 11, and 12 on the
page following these figures

and Two--Speed Air Conditioner

A03183

A03184

FOR FIGURES 26--32

1. Heat pump MUST have a high pressure switch for dual fuel applications.

2. Refer to outdoor equipment Installation Instructions for additional information and setup procedure.

3. Outdoor Air Temperature Sensor must be attached in all dual fuel applications.

4. Dip switch No. 1 on Thermidistat should be set in OFF position for air conditioner installations. This is factory default.

5. Dip switch No. 1 on Thermidistat should be set in ON position for heat pump installations.

6. Dip switch No. 2 on Thermidistat should be set in OFF position for single---speed compressor operation. This is factory default.

7. Dip switch No. 2 on Thermidistat should be set in ON position for two --- speed compressor operation.

8. Configuration Option No. 10 “Dual Fuel Selection” must be turned ON in all dual fuel applications.

9. NO connection should be made to the furnace HUM terminal when using a Thermidistat.

10. Optional connection: If wire is connected, dip switch SW1---2 on furnace control should be set in ON position to allow Thermidistat/Thermostat to control
furnace staging.

11. Optional connection: If wire is connected, ACRDJ jumper on furnace control should be removed to allow Thermidistat/Thermostat to control outdoorunit
staging.

12. When using both a two---stage furnace and a two---stage heat pump, the furnace must control its own high ---stage heating operation via furnace control
algorithm.

13. The RVS Sensing terminal “L” should not be connected. This is internally used to sense defrost operation.

14. DO NOT SELECT the “FURNACE INTERFACE” or “BALANCE POINT” option on the two ---speed heat pump control board. This is controlled internally by
the Thermidistat/Dual Fuel Thermostat.

15. Dip switch D on Dual Fuel T hermostat should be set in OFF position for single - --speed compressor operation. This is factor y default.

16. Dip switch D on Dual Fuel Thermostat should be set in ON position for two---speed compressor operation.

24

ACCESSORIES

1. Electronic Air Cleaner (EAC)
Connect an accessory Electronic Air Cleaner (if used) us­ing 1/4--in female quick connect terminals to the two male
1/4--in quick--connect terminals on the control board
marked EAC--1 and EAC--2. The terminals are rated for
115VAC, 1.0 amps maximum and are energized during
blower motor operation. (See Fig. 33.)

2. Humidifier (HUM)
Connect an accessory 24 VAC, 0.5 amp. maximum hu­midifier (if used) to the 1/4--in male quick--connect HUM
terminal and COM--24V screw terminal on the control
board thermostat strip. The HUM terminal is energized
when gas valve relay (GVR) is energized. (See Fig. 33.)

NOTE: A field--supplied, 115--v controlled relay connected to
EAC terminals may be added if humidifier operation is desired
during blower operation.

SETUP SWITCHES

LOW-HEAT ONLY AND

BLOWER OFF-DELAY

W2

Y1 DHUM G COM

LHT
OFF
DLY

TWINNING AND/OR
COMPONENT TEST

TERMINAL

ON

OFF

1 2 3

NOTE: DO NOT connect furnace control HUM terminal to
HUM (humidifier) terminal on Thermidistat, Zone Controller or
similar device. See Thermidistatt, Zone Controller, thermostat,
or controller manufacturer’s instructions for proper connection.

VENTING

The furnace shall be connected to a listed factory built chimney
or vent or a clay--tile lined masonry or concrete chimney. Venting
into an unlined masonry chimney or concrete chimney is
prohibited. When an existing Category I furnace is removed or
replaced, the original venting system may no longer be sized to
properly vent the attached appliances. An improperly sized
Category I venting system could cause the formation of
condensate in the furnace and vent, leakage of condensate and
combustion products, and spillage of combustion products into
the living space.

ACRDJ - AIR CONDITIONING

RELAY DISABLE JUMPER

312AAV

24-V-THERMOSTAT
TERMINALS

HUMIDIFIER TERMINAL

(24-VAC 0.5 AMP MAX.)

3-AMP FUSE

LED OPERATION &

DIAGNOSTIC LIGHT

115-VAC (L2) NEUTRAL

CONNECTIONS

HI HEAT
LO HEAT

BLOWER SPEED

SELECTION TERMINALS

24V

WW1 Y/Y2 R

S

E

L

EAC-2

BLW

HI HEAT LO HEAT

SPARE-1

SPARE-2

TEST/TWIN

HUM

0.5-AMP024 VAC

FUSE 3-AMP

A

T

T

SEC-1 SEC-2

U

S

C

O

E

D

NEUTRAL-L2

COOL

SPARE-1 SPARE-2

Fig. 33 -- Furnace Control--PSC Blower Motor

ACRDJ

PLT

PL1

1

BHT/CLRBHI/LOR

1-AMP@115 VAC

EAC-1 PR-1

COOL

D

BLWR

IDR

L1

115-VAC (L1) LINE

VOLTAGE CONNECTION

EAC-1 TERMINAL

(115-VAC 1.0 AMP MAX.)

1

PL2

HSI HI LO

HSIR

TRANSFORMER 24-VAC

CONNECTIONS

PL1 - LOW VOLTAGE MAIN

HARNESS CONNECTOR

PL3 1

PL3

IHI/LOR

IDM

PL2 - HOT SURFACE

IGNITER & INDUCER

MOTOR CONNECTOR

A02017

25

!

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. 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:

1. Seal any unused openings in venting system.

2. Inspect the venting system for proper size and
horizontal pitch, as required in the National Fuel Gas
Code, ANSI Z223.1/NFPA 54 and these
instructions. Determine that there is no blockage or
restriction, leakage, corrosion and other deficiencies,
which could cause an unsafe condition.

3. As far as practical, close all building doors and

312AAV

Vent system or vent connectors may need to be resized. Vent
systems or vent connectors must be sized to approach minimum
size as determined using appropriate table found in the NFGC.

GENERAL VENTING

Follow all safety codes for proper vent sizing and installation
requirements, including local building codes, the National Fuel
Gas Code ANSI Z223.1--2009/NFPA 54--2009 (NFGC), Parts 12
and 13 in the United States, the local building codes, and furnace
and vent manufacturers’ instructions.

These furnaces are design--certified as Category I furnaces in
accordance with ANSI Z21.47--2006/CSA 2.3--2006 and operate
with a non--positive vent static pressure to minimize the potential
for vent gas leakage. Category I furnaces operate with a flue loss
not less than 17% to minimize the potential for condensation in
the venting system. These furnaces are approved for common
venting and multi--story venting with other fan assisted or draft

windows and all doors between the space in which
the appliance(s) connected to the venting system are
located and other spaces of the building.

4. Close fireplace dampers.

5. Turn on clothes dryers and any appliance not
connected to the venting system. Turn on any
exhaust fans, such as range hoods and bathroom
exhausts, so they are operating at maximum speed.
Do not operate a summer exhaust fan.

6. Follow the lighting instructions. Place the appliance
being inspected into operation. Adjust the thermostat
so appliance is operating continuously.

7. Test for spillage from draft hood equipped
appliances at the draft hood relief opening after 5
minutes of main burner operation. Use the flame of a
match or candle.

8. If improper venting is observed during any of the
above tests, the venting system must be corrected in
accordance with the National Fuel Gas Code, ANSI
Z223.1/NFPA 54.

9. After it has been determined that each appliance
connected to the venting system properly vents when
tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other
gas--fired burning appliance to their previous
conditions of use.

REQUIREMENTS

hood equipped appliances in accordance with the NFCG, local
building codes, and furnace and vent manufacturers’ instructions.

The following information and warning must be considered in
addition to the requirements defined in the NFGC.

!

WARNING

CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in personal
injury or death.

Do not bypass the draft safeguard switch, as an unsafe
condition could exist which must be corrected.

1. If a vent (common or dedicated) becomes blocked, the fur­nace will be shut off by the draft safeguard switch located
on the vent elbow.

2. Two--stage furnaces require Type B vent connectors out­side the casing in all configurations. Single wall vent con­nector may be used inside the furnace casing with the
transition to Type B vent outside the furnace casing. Size
the connector so that the FAN--Min vent connector capa­city is equal to or lower than the low fire rate of the fur­nace and the FAN--Max vent connector capacity is equal
to or higher than the furnace high fire rate.

3. Do not vent this Category I furnace into a single wall ded­icated or common vent. The dedicated or common vent is
considered to be the vertical portion of the vent system
that terminates outdoors.

4. Vent connectors serving Category I furnaces shall not be
connected into any portion of a mechanical draft system
operating under positive pressure.

5. Do not vent this appliance with any solid fuel burning ap­pliance.

6. Category I furnaces must be vented vertically or nearly
vertically unless equipped with a listed mechanical venter.
See the SIDEWALL VENTING section.

7. Do not vent this appliance into an unlined masonry chim­ney. Refer to Chimney Inspection Chart, Fig. 34.

MASONRY CHIMNEY
NOTE: These furnaces are CSA design--certified for use in

exterior tile--lined masonry chimneys with a factory accessory
Chimney Adapter Kit. Refer to the furnace rating plate for correct
kit usage. The Chimney Adapter Kits are for use with ONLY
furnaces having a Chimney Adapter Kit number marked on the
furnace rating plate.

If a clay tile--lined masonry chimney is being used and it is
exposed to the outdoors below the roof line, relining might be
required. Chimneys shall conform to the Standard for Chimneys,
Fireplaces, Vents, and Solid Fuel Burning Appliances
ANSI/NFPA 211--2009 in the United States and must be in good
condition.

U.S.A.--Refer to Sections 13.1.8 and 13.2.20 of the NFPA 54 /
ANSI Z223.1--2009 or the authority having jurisdiction to
determine whether relining is required. If relining is required, use
a properly sized listed metal liner, Type--B vent, or a listed
alternative venting design.

NOTE: See the NFPA 54 / ANSI Z223.1--2009, 13.1.8 and

13.2.20 regarding alternative venting design and the exception,
which cover installations such as the Chimney Adapter Kits
which are listed for use with these furnaces. See Table 18 for
accessory listing.

REQUIREMENTS

26

312AAV

Fig. 34 -- Chimney Inspection Chart

27

A10133

The Chimney Adapter Kit is a listed alternative venting system
for these furnaces. See the kit instructions for complete details.

This furnace is permitted to be vented into a clay tile--lined
masonry chimney that is exposed to the outdoors below the roof
line, provided:

1. Vent connector is Type--B double--wall, and

2. This furnace is common vented with at least 1 draft hood-­equipped appliance, and

3. The combined appliance input rating is less than the max­imum capacity given in Table 8, and

4. The input rating of each space heating appliance is greater
than the minimum input rating given in Table 9 for the
local 99% Winter Design Temperature. Chimneys having
internal areas greater than 38 in

2

(24516 mm2)require fur­nace input ratings greater than the input ratings of these
furnaces. See footnote at bottom of Table 9, and

5. The authority having jurisdiction approves.

If all of these conditions cannot be met, an alternative venting
design shall be used, such as the listed chimney adapter kit with a

312AAV

furnace listed for use with the kit, a listed chimney--lining system,
or a Type--B common vent.

Inspections before the sale and at the time of installation will
determine the acceptability of the chimney or the need for repair
and/or (re)lining. Refer to Fig. 34 to perform a chimney
inspection. If the inspection of a previously used tile--lined
chimney:

a. Shows signs of vent gas condensation, the chimney

should be relined in accordance with local codes and the
authority having jurisdiction.The chimneyshould be re­lined with a listed metal liner, Type--B vent, or a listed
chimney adapterkitshallbeusedtoreducecondensation.
If a condensate drain is required by local code, refer to
theNFPA 54 /ANSIZ223.1--2009,Section12.10 for ad­ditional information on condensate drains.

b. Indicates the chimney exceeds the maximum permissible

sizein the tables,thechimneyshould be rebuilt or relined
to conform to the requirements of the equipment being
installed and the authority having jurisdiction.

A chimney without a clay tile liner, which is otherwise in good
condition, shall be rebuilt to conform to ANSI/NFPA 211 or be
lined with a UL listed metal liner or UL listed Type--B vent.
Relining with a listed metal liner or Type--B vent is considered to
be a vent--in--a--chase.

If a metal liner or Type--B vent is used to line a chimney, no other
appliance shall be vented into the annular space between the
chimney and the metal liner.

Exterior Masonry Chimney FAN + NAT

Installationswith Type--B Double--Wall Vent

Connectors ENFPA & AGA

Table 8 – Combined Appliance Maximum Input Rating in

Thousands of BTUH per Hour

INTERNAL AREA OF CHIMNEY

VENT HEIGHT

FT. (M)

6 (1.8) 74 119 178 257
8 (2.4) 80 130 193 279

10 (3.) 84 138 207 299
15 (4.5) NR 152 233 334
20 (6.0) NR NR 250 368
30 (9.1) NR NR NR 404

12

(7741)19(12258)28(18064)38(24516)

SQ. IN. (SQ. MM)

Table 9 – Minimum Allowable Input Rating of Space--Heat-

ing Appliance in Thousands of BTUH per Hour

INTERNAL AREA OF CHIMNEY

VENT HEIGHT

(FT)

Temperature: 17 to 26_F ( --- 8 t o --- 3 _C)

6 (1.8) 0 55 99 141

8 (2.4) 52 74 111 154

10 (3.0) NR 90 125 169

15 (4.6) NR NR 167 212

20 (6.1) NR NR 212 258

30 (9.1) NR NR NR 362

Temperature: 5 to 16 _F * ( --- 1 5 t o --- 9 _C)

6 (1.8) NR 78 121 166

8 (2.4) NR 94 135 182

10 (3.0) NR 111 149 198

15 (4.6) NR NR 193 247

20 (6.1) NR NR NR 293

30 (9.1) NR NR NR 377

Temperature: ---10 to 4_F * ( --- 2 3 t o --- 1 6 _C)

6 (1.8) NR NR 145 196

8 (2.4) NR NR 159 213

10 (3.0) NR NR 175 231

15 (4.6) NR NR NR 283

20 (6.1) NR NR NR 333

30 (9.1) NR NR NR NR

Temperature: ---11_F ( --- 2 4 _C) or lower

Not recommended for any vent configuration.

*The 99.6% heating db temperatures found in the 1997 or 2001 ASHRAE
Fundamentals Handbook, Climatic Design Information chapter, Table 1A
(United States) or the 2005 ASHRAE Fundamentals handbook, Climatic
Design Information chapter, and the CD---ROM included with the 2005
ASHRAE Fundamentals Handbook.

12

(7741)19(12258)28(18064)38(24516)

Local 99% Winter Design

Local 99% Winter Design

Local 99% Winter Design

Local 99% Winter Design

SQ. IN. (SQ. MM)

APPLIANCE APPLICATION REQUIREMENTS

Appliance operation has a significant impact on the performance
of the venting system. If the appliances are sized, installed,
adjusted, and operated properly, the venting system and/or the
appliances should not suffer from condensation and corrosion.
The venting system and all appliances shall be installed in
accordance with applicable listings, standards, and codes.

The furnace should be sized to provide 100% of the design
heating load requirement plus any margin that occurs because of
furnace model size capacity increments. Heating load estimates
can be made using approved methods available from Air
Conditioning Contractors of America (Manual J); American
Society of Heating, Refrigerating, and Air--Conditioning
Engineers; or other approved engineering methods. Excessive
over--sizing of the furnace could cause the furnace and/or vent to
fail prematurely. When a metal vent or metal liner is used, the
vent must be in good condition and be installed in accordance
with the vent manufacturer’s instructions.

To prevent condensation in the furnace and vent system, the
following precautions must be observed:

1. The return--air temperature must be at least 60_F(15_C)
db except for brief periods of time during warm--up from
setback at no lower than 55_F(13_C) db or during initial
start--up from a standby condition.

28

2. Adjust the gas input rate per the installation instructions.
Low gas input rate causes low vent gas temperatures, caus­ing condensation and corrosion in the furnace and/or vent­ing system. Derating is permitted only for altitudes above
2000 ft

3. Adjust the air temperature rise to the midpoint of the rise
range or slightly above. Low air temperaturerise can cause
low vent gas temperature and potential for condensation
problems.

4. Set the thermostat heat anticipator or cycle rate to reduce
short cycling.

Air for combustion must not be contaminated by halogen
compounds which include chlorides, fluorides, bromides, and
iodides. These compounds are found in many common home
products such as detergent, paint, glue, aerosol spray, bleach,
cleaning solvent, salt, and air freshener, and can cause corrosion
of furnaces and vents. Avoid using such products in the

See Venting Notes after Fig. 47.

combustion--air supply. Furnace use during construction of the
building could cause the furnace to be exposed to halogen
compounds, causing premature failure of the furnace or venting
system due to corrosion.

Vent dampers on any appliance connected to the common vent
can cause condensation and corrosion in the venting system. Do
not use vent dampers on appliances common vented with this
furnace.

ADDITIONAL VENTING

REQUIREMENTS

A 4 in. (102 mm) round vent elbow is supplied with the furnace.
A 5 in. or 6 in. (127 or 152 mm) vent connector may be required
for some model furnaces. A field--supplied 4 in. to 5 in. (102 to
127 mm) or 4 in. to 6 in. (102 mm to 152 mm) sheet metal
increaser fitting is required when 5 in. or 6 in. (127 or 152 mm)
vent connector is used. See Fig. 35--47 Venting Orientation for
approved vent configurations.

312AAV

SEE NOTES: 1,2,4,7,8,9
on the page following
these figures

Fig. 35 -- Upflow Application--Vent Elbow Up

A03208

SEE NOTES: 1,2,3,4,7,8,9
on the pages following
these figures

Fig. 36 -- Upflow Application--Vent Elbow Right

A03209

29

312AAV

SEE NOTES:1,2,3,4,5,7,8,9
on the page following
these figures

SEE NOTES: 1,2,4,5,6,7,8,9,10
on the page following these figures

A03210

Fig. 37 -- Downflow Application--Vent Elbow Up then Left

SEE NOTES: 1,2,4,5,7,8,9
on the page following
these figures

A03207

Fig. 39 -- Downflow Application--Vent Elbow Left then Up

SEE NOTES:1,2,3,4,5,7,8,9
on the page following
these figures.

Fig. 38 -- Downflow Application--Vent Elbow Up

A03211

A03212

Fig. 40 -- Downflow Application--Vent Elbow Up then Right

30

SEE NOTES: 1,2,4,7,8,9 on the page
following these figures

A03213

Fig. 41 -- Horizontal Left Application -- Vent Elbow Left

SEE NOTES: 1,2,4,5,7,8,9 on the page
following these figures

A03215

Fig. 44 -- Horizontal Left Application -- Vent Elbow Up

312AAV

SEE NOTES: 1,2,4,5,7,8,9 on the page
following these figures

Fig. 42 -- Horizontal Left Application -- Vent Elbow Right

then Up

SEE NOTES: 1,2,4,7,8,9 on the page
following these figures

Fig. 43 -- Horizontal Right Application -- Vent Elbow Right

A03214

A03218

SEE NOTES: 1,2,4,5,7,8,9 on the page
following these figures

Fig. 45 -- Horizontal Left Application -- Vent Elbow Right

SEE NOTES: 1,2,4,5,7,8,9 on the page
following these figures

Fig. 46 -- Horizontal Right Application -- Vent Elbow Left

then Up

A03216

A03219

31

SEE NOTES: 1,2,4,5,7,8,9

A02068

Fig. 47 -- Horizontal Right Application--Vent Elbow Left

VENTING NOTES FOR FIG. 35 -- 47

1. For common vent, vent connector sizing and vent material: United States--use the NFGC.

2. Immediately increase to 5--in. or 6--in. (127 or 152 mm) vent connector outside furnace casing when 5--in. (127 mm) vent connector is
required, refer to Note 1 above.

3. Side outlet vent for upflow and downflow installations must use Type B vent immediately after exiting the furnace, except when

312AAV

factory--approved Downflow Vent Guard Kit, is used in the downflow position. See Table 18 for accessory listing.

4. Type--B vent where required, refer to Note 1 above.

5. Four--in. (102 mm) single--wall (26 ga. min.) vent must be used inside furnace casing and when the factory--approved Downflow Vent
Guard Kit is used external to the furnace. See Table 18 for accessory listing.

6. Accessory Downflow Vent Guard Kit required in downflow installations with lower vent configuration. See Table 18 for accessory
listing.

7. Chimney Adapter Kit may be required for exterior masonry chimney applications. Refer to Chimney Adapter Kit for sizing and
complete application details. See Table 18 for accessory listing.

8. Secure vent connector to furnace elbow with (2) corrosion--resistant sheet metal screws, spaced approximately 180_ apart.

9. Secure all other single wall vent connector joints with (3) corrosion resistant screws spaced approximately 120_ apart. Secure Type--B
vent connectors per vent connector manufacturer’s recommendations.

10. The total height of the vent and connector shall be at least seven feet (2 M) for the 154,000 Btuh gas input rate model when installed
in a downflow application with furnace elbow turned to left side with the connector elbow outside furnace casing pointing upward.
(See Fig. 40.)

Caution!! For the following applications, use the minimum vertical heights as specified below.

For all other applications, follow exclusively the National Fuel Gas Code

FURNACE

ORIENTATION

Downflow

Horizontal Left

Horizontal Left

Horizontal Left

Downflow

Downflow

*4 in . (102 mm) inside casing or vent guard
**Including 4 in. (102 mm) vent section(s)
NOTE: All vent configurations must also meet National Fuel Gas Code venting requirements NFGC.

VENT

ORIENTATION

Vent elbow left, then

up Fig. 39

Vent elbow right,

then up Fig. 42

Vent Elbow up Fig.

43

Vent elbow right Fig.

44

Vent elbow up then

left Fig. 37

Vent elbow up, then

right Fig. 40

FURNACE

INPUT(BTUH/HR)

154,000
132,000

110,000 (036/ --- 12 only)

154,000
132,000

154,000
132,000

154,000 5 (127) 7 (.65)

110,000 (036/ --- 12 only) 5 (127) 10 (3.0)

110,000 (036/ --- 12 only) 5 (127) 10 (3.0)

MINIMUM VENT

DIAMETER

IN. (mm)*

MINIMUM VERTICAL

VENT HEIGHT

FT. (M)**

5 (127) 12 (3.6)

5 (127) 7 (.65)

5 (127) 7 (.65)

32

!

CUT HAZARD

Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care

and wear appropriate protective clothing, safety glasses and
gloves when handling parts and servicing furnaces.

NOTE: Vent connector length for connector sizing starts at
furnace vent elbow. The 4--in. (102 mm) vent elbow is shipped
for upflow configuration and may be rotated for other positions.
Remove the 3 screws that secure vent elbow to furnace, rotate
furnace vent elbow to position desired, re--install screws. The
factory--supplied vent elbow does NOT count as part of the
number of vent connector elbows.

The vent connector can exit the furnace through one of 5
locations on the casing.

1. Attach the single wall vent connector to the furnace vent
elbow, and fasten the vent connector to the vent elbow
with at least two field--supplied, corrosion--resistant, sheet
metal screws located 180_ apart.

NOTE: An accessory flue extension is available to extend from
the furnace elbow to outside the furnace casing. See Table 18 for
accessory listing. If flue extension is used, fasten the flue
extension to the vent elbow with at least two field--supplied,
corrosion--resistant, sheet metal screws located 180_ apart. Fasten
the vent connector to the flue extension with at least two
field--supplied, corrosion resistant sheet metal screws located
180_ apart.

2. Vent the furnace with the appropriate connector as shown
in Fig. 35--47.

3. Determine the correct location of the knockout to be re­moved.

4. Use a hammer and screwdriver to strike a sharp blow
between the tie points and work the slug back and forth
until the slug breaks free.

!

BURN HAZARD

Failure to follow this caution may cause personal injury.
Hot vent pipe is within reach of small children when

installed in downflow position.
See the following instruction.

An accessory Vent Guard Kit, is REQUIRED for downflow
applications where the vent exits through the lower portion of the
furnace casing. (See Fig. 39.) Refer to the Vent Guard Kit
Instructions for complete details and see Table 18 for accessory
listing.

The horizontal portion of the venting system shall slope upwards
not less than 1/4--in. per linear ft. (6 mm/.3 M) from the furnace
to the vent and shall be rigidly supported every 5 ft. (1.5 M) or

CAUTION

CAUTION

less with metal hangers or straps to ensure there is no movement
after installation.

SIDEWALL VENTING
This furnace is not approved for direct sidewall horizontal

venting.
In the U.S.: Per section 12.4.3 of the NFPA 54 / ANSI

Z223.1--2009, any listed mechanical venter may be used, when
approved by the authority having jurisdiction.

Select the listed mechanical venter to match the Btuh input of the
furnace being vented. Follow all manufacturer’s installation
requirements for venting and termination included with the listed
mechanical venter.

START--UP, ADJUSTMENT, AND SAFETY

CHECK

Step 1 — General

!

WARNING

FIRE HAZARD

Failure to follow this warning could result in personal
injury, death and/or property damage.

This furnace is equipped with manual reset limit switches in
the gas control area. The switches open and shut off power
to the gas valve if a flame roll--out or overheating condition
occurs in the gas control area. DO NOT bypass the
switches. Correct problem before resetting the switches.

1. Maintain 115--v wiring and ground. Improper polarity will
result in rapid flashing LED and no furnace operation.

2. Make thermostat wire connections at the 24--v terminal
block on the furnace control. Failure to make proper con­nections will result in improper operation. (See Fig. 33.)

3. Gas supply pressure to the furnace must be greater than

4.5--In. W.C. (0.16 psig ) but not exceed 14--In. W.C. (0.5
psig).

!

CAUTION

CUT HAZARD

Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care

and wear appropriate protective clothing, safety glasses and
gloves when handling parts and servicing furnaces.

4. Check all manual--reset switches for continuity.

5. Install blower compartment door. Door must be in place to
operate furnace.

6. Setup switch descriptions The 2 stage furnace has DIP
switches used to select thermostat staging and blower off
delay timings. For switch locations on Furnace control
board, See Fig. 33 and 52.

7. Setup switch descriptions -- See Table 10.

312AAV

33

Table 10 – 2--Stage Furnace Setup Switch Description

SETUP

SWITCH NO.

S W --- 1 Adaptive Heat Mode OFF

S W --- 2 Blower OFF delay ON or OFF

S W --- 3 Blower OFF delay ON or OFF

SWITCH

NAME

Step 2 — Start--Up Procedures

!

WARNING

FIRE AND EXPLOSION HAZARD

Failure to follow this warning could cause personal injury,
death and/or property damage.

Never test for gas leaks with an open flame. Use a

312AAV

commercially available soap solution made specifically for
the detection of leaks to check all connections.

1. Purge gas lines after all connections have been made.

2. Check gas lines for leaks.

!

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal
injury, or death.

Blower access door switch opens 115--v power to control.
No component operation can occur unless switch is closed.
Caution must be taken when manually closing this switch
for service purposes.

3. To Begin Component Self--Test:
Remove blower access door. Disconnect the thermostat R
lead from furnace control board. Manually close blower
door switch. Short (jumper) the COM--24v terminal on
control to the TEST/TWIN 3/16--in. (8 mm) quick--con­nect terminal on control until the LED goes out (approx­imately 2 sec). Gas valve and humidifier will not be turned
on. Remove jumper from terminals. (See Fig. 33 and
Table 10.)

NOTE: The furnace control allows all components, except the
gas valve, to be run for short period of time. This feature helps
diagnose a system problem in case of a component failure.
Component test feature will not operate if any thermostat signal is
present at the control.

Refer to service label attached to furnace or See Fig. 51.
Component test sequence is as follows:

a. LED will display previous status code 4 times.

b. Inducer motor startson high--speed and continuesto run

until Step g of component test sequence.

c. Hot surface igniter is energized for 15 sec., then off.

d. Blower motor operates on LO--HEAT speed for 10 sec.

e. Blower motor operates on HI--HEAT speed for 10 sec.

f. Blower motor operates on COOL speed for 10 sec.
g. Inducer motor goesto low--speed for 10 sec., then stops.
h. Reconnect R lead to furnace control board, remove tape

from blower door switch and re--install blower door.

4. Operate furnace per instruction on inner door.

NORMAL

POSITION

DESCRIPTION

When OFF, allows 2--- stage operation with a single stage thermostat.
Turn ON when using 2 stage thermostat to allow Low Heat operation

when R to W/W1 closes and High Heat operation when R to W/W1

Control blower OFF delay time. Used in conjunction with SW---3.

Control blower OFF delay time. Used in conjunction with SW---2.

5. Verify furnace shut down by lowering thermostat setting
below room temperature.

6. Verify furnace restarts by raising thermostat setting above
room temperature.

OF USE

and W2 close.

See Table 14.

See Table 14.

Step 3 — Adjustments

!

WARNING

FIRE HAZARD

Failure to follow this warning could result in injury, death
and/or property damage.

DO NOT bottom out gas valve regulator adjusting screw.
This can result in unregulated manifold pressure and result
in excess over--fire and heat exchanger failures.

!

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in reduced furnace
life.

DO NOT re--drill orifices. Improper drilling (burrs, out--of
round holes, etc.) can cause excessive burner noise and
misdirection of burner flames. This can result in flame
impingement of heat exchangers, causing failures.

Furnace gas input rate on rating plate is for installations at
altitudes up to 2000 ft. (610 M). Furnace input rate must be
within +/--2% of furnace rating plate input. For altitudes above
5500 ft. (1676 M), a field--supplied high altitude pressure switch
is required.

1. Determine the correct gas input rate.
The input rating for altitudes above 2,000 ft. (610 M) must
be reduced by 4% for each 1,000 ft. (305 M) above sea
level.
For installations below 2000 ft. (610 M), refer to the unit
rating plate.
For installations above 2000 ft. (610 M), multiply the in­put on the rating plate by the derate multiplier in Table 11
for the correct input rate.

2. Determine the correct orifice and manifold pressure adjust­ment. All models in all positions except Low NOx models
in downflow and horizontal positions use Table 15
(22,000 BTUH per burner).

34

Table 11 – Altitude Derate Multiplier for U.S.A.

ALTITUDE

FT. (M)

0–2000

(0--- 610)

2001–3000
(610--- 914)

3001–4000

(914--- 1219)

4001–5000

(1219--- 1524)

5001–6000

1524--- 1829)

6001–7000

(1829--- 2134)

7001–8000

(2134--- 2438)

8001–9000

(2438--- 2743)

9001–10,000

(2743--- 3048)

* Derate mu l tiplier factors are based on midpoint altitude for altitude
range.

PERCENT

OF DERATE

0 1.00

8–12 0.90

12–16 0.86

16–20 0.82

20–24 0.78

24–28 0.74

28–32 0.70

32–36 0.66

36–40 0.62

DERATE MULTIPLIER

FACTOR*

Low NOx models in downflow or horizontal positions MUST
use Table 16 (21,000 BTUH per burner). See input listed on
rating plate.

a. Obtain average yearly gas heatvalue (atinstalled altitude)

from local gas supplier.

b. Obtain average yearly gas specific gravity from local gas

supplier.

c. Find installation altitude in Table 15 or 16.

d. Find closest natural gas heat value and specific gravity

in Table 15 or 16.

e. Follow heat value and specific gravity lines to point of

intersection to find orifice size and low--and high--heat
manifold pressure settings for proper operation.

f. Check and verify burner orifice size in furnace. NEVER

ASSUME ORIFICE SIZE. ALWAYS CHECK AND
VERIFY.

g. Replace orifice with correct size, if required by Table 15

or 16. Use only factory--supplied orifices. See
EXAMPLE 1.

EXAMPLE 1: (0--2000 ft. / 0--610 M altitude)
For 22,000 Btuh per burner application, use Table 15.
Heating value = 1000 Btuh/cu ft.
Specific gravity = 0.62
Therefore: Orifice No. 43*
Manifold pressure: 3.7--In. W.C. for high--heat

1.6--In. W.C. for low--heat
* Furnace is shipped with No. 43 orifices. In this example
all main burner orifices are the correct size and do not need
to be changed to obtain proper input rate.

3. Adjust manifold pressure to obtain low fire input rate. (See
Fig. 48.)

a. Turn gas valve ON/OFF switch to OFF.

b. Remove manifold pressure tap plug from gas valve.

c. Connect a water column manometer or similar device to

manifold pressure tap.

d. Turn gas valve ON/OFF switch to ON.

312AAV

A06667

Fig. 48 -- Redundant Automatic Gas Control Valve

e. Move setup switch LHT (SW--1) on furnace control to

ON position to lock furnace in low--heat operation. (See
Fig. 33 and Table 10.)

f. Manually close blower door switch.

g. Jumper R and W/W1 thermostat connectionson control

to start furnace. (See Fig. 33.)

h. Remove regulator adjustment cap from low--heat gas

valve pressure regulators. (See Fig. 48.) Turn low--heat
adjusting screw (3/16 in. (5 mm) or smaller flat tipped
screwdriver) counterclockwise (out) to decrease input
rate or clockwise (in) to increase input rate.

NOTE: DO NOT set low--heat manifold pressure less than

1.4--In. W.C. or more than 1.7--In. W.C. for natural gas. If
manifold pressure is outside this range, change main burner
orifices.

i. Install low--heat regulator adjustment cap.
j. Leave manometer or similar device connected and pro-

ceed to Step 4.

NOTE: If orifice hole appears damaged or it is suspected to have
been re--drilled, check orifice hole with a numbered drill bit of
correct size. Never re--drill an orifice. A burr--free and squarely
aligned orifice hole is essential for proper flame characteristics.

4. Verify natural gas low--heat input rate by clocking meter.

NOTE: Gas valve regulator adjustment caps must be in place for
proper input to be clocked.

a. Turn off all other gas appliances and pilots served by the

meter.
b. Run for 3 minutes in low--heat operation.
c. Measure time (in sec) for gas meter to complete 1revolu-

tion and note reading. The 2 or5 cubic feet dialprovides

a more accurate measurement of gas flow.

35

cified on unit rating plate for high--and low--heat.
Determine the temperature rise as follows:

NOTE: Blower access door must be installed when taking
temperature rise reading. Leaving blower access door off will
result in incorrect temperature measurements.

!

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal

BURNER

ORIFICE

A93059

Fig. 49 -- Orifice Hole

312AAV

d. Refer to Table 12 for cubic ft. of gas per hr.

e. Multiply gas rate cu ft. /hr by heating value (Btuh/cu ft.

) to obtain input. If clocked rate doesnot match required
input from Step 1, increase manifold pressureto increase
input or decrease manifold pressure to decrease input.
Repeat steps b through e until correct low heat input is
achieved. Re--install low--heat regulator seal cap on gas
valve.

5. Set low--heat temperature rise. The furnace must operate
within the temperature rise ranges specified on the furnace
rating plate. Do not exceed temperature rise ranges spe-

injury or death.
Disconnect 115--v electrical power and install lockout tag

before changing speed tap.

a. Verify unit is running in low heat per Step 3. Place ther-

mometers in return and supply ducts as close to furnace
aspossible.Be sure thermometersdo notsee radiantheat
from heat exchangers. Radiant heat affects temperature
rise readings. This practice is particularly important with
straight--run ducts.

b. When thermometer readings stabilize, subtract return--air

temperaturefromsupply--airtemperatureto determineair
temperature rise.

NOTE: If the temperature rise is outside this range, first check:

(1.) Gas input for low heat operation.
(2.) Derate for altitude if applicable.
(3.) Return and supply ducts for excessive restrictions

causing static pressures greater than 0.50--In. W.C.

36

Table 12 – Gas Rate (cu ft. /hr)

SECONDS

FOR

REVOLUTION

1

10 360 720 1800 50 72 144 360
11 327 655 1636 51 71 141 355
12 300 600 1500 52 69 138 346
13 277 555 1385 53 68 136 340
14 257 514 1286 54 67 133 333
15 240 480 1200 55 65 131 327
16 225 450 1125 56 64 129 321
17 212 424 1059 57 63 126 316
18 200 400 1000 58 62 124 310
19 189 379 947 59 61 122 305
20 180 360 900 60 60 120 300
21 171 343 857 62 58 116 290
22 164 327 818 64 56 112 281
23 157 313 783 66 54 109 273
24 150 300 750 68 53 106 265
25 144 288 720 70 51 103 257
26 138 277 692 72 50 100 250
27 133 267 667 74 48 97 243
28 129 257 643 76 47 95 237
29 124 248 621 78 46 92 231
30 120 240 600 80 45 90 225
31 116 232 581 82 44 88 220
32 113 225 563 84 43 86 214
33 109 218 545 86 42 84 209
34 106 212 529 88 41 82 205
35 103 206 514 90 40 80 200
36 100 200 500 92 39 78 196
37 97 195 486 94 38 76 192
38 95 189 474 96 38 75 188
39 92 185 462 98 37 74 184
40 90 180 450 100 36 72 180
41 88 176 439 102 35 71 178
42 86 172 429 104 35 69 173
43 84 167 419 106 34 68 170
44 82 164 409 108 33 67 167
45 80 160 400 110 33 65 164
46 78 157 391 112 32 64 161
47 76 153 383 116 31 62 155
48 75 150 375 120 30 60 150
49 73 147 367

SIZE OF TEST DIAL

1 CUFT. 2 CUFT. 5 CUFT. 1 CUFT. 2 CUFT. 5 CUFT.

SECONDS

FOR

REVOLUTION

1

SIZE OF TEST DIAL

312AAV

c. Adjust airtemperature rise by adjusting blower speed.In-

crease blower speed to reduce temperature rise. Decrease
blower speed to increase temperature rise. For low heat,
speed selection can be low (factory setting), med--low,or
med (5--speed blowers only).

d. Remove thermostat jumpers and remove Blower Access

Door.

e. To change motor speed selection for low heat, remove

blower motor lead from control LO--HEAT terminal.
(See Fig. 33.) Select desired blower motor speed lead
from 1 of the other terminals and relocate it to the LO-­HEAT terminal. (See Table 13 for lead color identifica­tion). Reconnect original lead to SPARE terminal.

f. Repeat steps a through e.

!

CAUTION

FURNACE OVERHEATING HAZARD

Failure to follow this caution may result in reduced furnace
life.

Recheck temperature rise. It must be within limits specified
on the rating plate. Recommended operation is at the
midpoint of rise range or slightly above.

g. When correct low heat input rate and temperature rise is

achieved, proceed to Step 6.

6. Adjust Manifold Pressure to Obtain High Heat Rate

a. Remove high fire regulator adjustment cap from gas

valve pressure regulator.

b. Jumper R, W/W1 and W2 thermostat connections on

control to run furnace in high heat. (See Fig. 33.)

c. d. Turn high--heat adjusting screw (3/16--in. (5 mm) or

smaller flat tipped screwdriver) counterclockwise (out)

to decrease input rate or clockwise (in) to increase rate.
d. Re--install high--fire adjustment caps.
e. Leave manifold or similar device connected and proceed

to Step 7.

NOTE: DO NOT set high--heat manifold pressure less than

3.2--In. W.C. or more than 3.8--In. W.C. for natural gas. If
manifold pressure is outside this range, change main burner
orifices.

7. Verify natural gas high heat input rate by clocking meter.

NOTE: Gas valve regulator adjustment caps must be in place for
proper input to be clocked.

a. Turn off all other gas appliances and pilots served by the

meter.
b. Run for 3 minutes in high--heat operation.
c. Measure time (in sec) for gas meter to complete 1revolu-

tion and note reading.
d. Refer to Table 12 for cubic ft. of gas per hr.
e. Multiply gas rate cu ft. /hr by heating value (Btuh/cu ft.)

to obtain input.

NOTE: Using the 2 cu. ft. or 5 cu. ft. gas meter dial provides
greater accuracy in verifying gas input rate.

37

If clocked rate does not match required input from Step 1,
increase manifold pressure to increase input or decrease manifold
pressure to decrease input. Repeat steps b through e until correct
high heat input is achieved. Re--install high--heat regulator seal
cap on gas valve.

8. Set high heat temperature rise.
Jumper R to W/W1 and W2 to check high--gas--heat tem­perature rise. Do not exceed temperature rise ranges spe­cified on furnace rating plate for high heat. The furnace
must operate within the temperature rise ranges specified
on the furnace rating plate.
Determine the air temperature rise as follows:

NOTE: Blower access door must be installed when taking
temperature rise reading. Leaving blower access door off will
result in incorrect temperature measurements.

a. Verify the furnace is operating in high heat per Step 6.

Place thermometers in return and supply ducts as close
to furnace as possible. Be sure thermometers do not see
radiant heat from heat exchangers. Radiant heat affects

312AAV

NOTE: If the temperature rise is outside this range, first check:

temperature risereadings.Thispractice isparticularly im­portant with straight--run ducts.

b. When thermometer readings stabilize, subtract return--air

temperaturefromsupply--airtemperatureto determineair
temperature rise.

(1.) Gas input for low--and high--heat operation.
(2.) Derate for altitude if applicable.
(3.) Return and supply ducts for excessive restrictions

causing static pressures greater than 0.50--In. W.C.

(4.) Dirty filter.

c. Adjust airtemperature rise by adjusting blower speed.In-

crease blower speed to reduce temperature rise. Decrease
blower speed to increase temperature rise. For high heat,
speed selection can be med--high, med (5--speed blowers
only), or med--low (factory setting).

!

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal
injury or death.

Disconnect 115--v electrical power and install lockout tag
before changing speed tap.

d. To change motor speed selection for high heat, remove

blowermotorleadfromcontrolHI--HEATterminal.(See
Fig. 33.) Select desired blower motor speed lead from
1 of the other terminals and relocate it to the HI--HEAT
terminal. DO NOT use the low--heat tap that was already
set. (See Table 13 for lead color identification). Recon­nect original lead to SPARE terminal.

e. Repeat steps a thru d.

f. When correcthigh heat input rateand temperatureriseis

achieved, turn gas valve ON/OFF switch to OFF.
g. Remove Blower Access Door.
h. Remove manometer or similar device from gas valve.

i. Re--install manifold pressure tap plug in gas valve. (See

Fig 54.)

!

WARNING

FIRE HAZARD

Failure to reinstall manifold pressure tap plug in gas valve
could result in personal injury, property damage or death.

Reinstall manifold pressure tap plug in gas valve to prevent
gas leak.

j. Remove thermostat jumper wire from furnace control

board.

k. Turn LHT switch OFF.

l. Turn gas valve ON/OFF switch to ON.

m. Proceed to Step 9, “Set Blower Off Delay” before in-

stalling blower access door.

!

CAUTION

FURNACE OVERHEATING HAZARD

Failure to follow this caution may result in reduced furnace
life.

Recheck temperature rise. It must be within limits specified
on the rating plate. Recommended operation is at the
midpoint of rise range or slightly above.

9. Set Blower Off Delay
a. Remove Blower Access Door if installed.
b. Turn Dip switch 2 and 3 ON or OFF for desired blower

off delay. (See Table 14 and Fig 34.)

10. Set thermostat heat anticipator.
a. Mechanical thermostat -- Set thermostat heat anticipator

to match the amp. draw of the electrical components in
the R--W/W1 circuit. Accurate amp. draw readings can
beobtainedatthewiresnormallyconnectedtothermostat
subbase terminals, R and W. The thermostat anticipator
should NOT be in the circuit while measuring current.

(1.) Set LHT switch on furnace control board to ON.
(2.) Remove thermostat from sub--base or from wall.
(3.) Connect an amp. meter as shown in Fig. 50 across

the R and Wsubbase terminals or R and W wires at
wall.

(4.) Record amp. draw across terminals when furnace is

in low heat and after blower starts.

(5.) Set heatanticipatoron thermostatper thermostat in-

structions and install on subbase or wall.
(6.) Turn LHT switch OFF.
(7.) Install blower access door.

b. Electronic thermostat: Set cycle rate for 3 cycles per hr.

11. Set airflow CFM for cooling
Select the desired blower motor speed lead for cooling air­flow. See Table 5--Air Delivery--CFM (With Filter). See
Table 13 for lead color identification.

Table 13 – Speed Selection

COLOR SPEED AS SHIPPED

White Common BLW

Black High COOL

Yellow M e d --- H i g h SPARE

Orange† Med SPARE

Blue M e d --- L o w HI--- HEAT
Red Low* LO HEAT

* Continuous --- blower speed --- as shipped default
{ Not all models equipped with 5 speed motors

38

Table 14 – 2--Stage Furnace Blower OFF delay Setup Switch

DESIRED HEATING MODE

BLOWER OFF DELAY (SEC.)

90 OFF OFF
120 OFF ON
150 ON OFF
180 ON ON

THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
(ANITICIPATOR, CLOCK, ETC.,
MUST BE OUT OF CIRCUIT.)

HOOK-AROUND

AMMETER

R Y W G

10 TURNS

FROM UNIT 24-V
CONTROL TERMINALS

EXAMPLE:

5.0 AMPS ON AMMETER
10 TURNS AROUND JAWS

0.5 AMPS FOR THERMOSTAT

=

ANTICIPATOR SETTING

A96316

Fig. 50 -- Amp. Draw Check with Ammeter

Step 4 — Check Safety Controls

The flame sensor, gas valve, and pressure switch were all checked
in the Start--up procedure section as part of normal operation.

1. Check Main Limit Switch(es)
This control shuts off combustion system and energizes
air--circulating blower motor, if furnace overheats. By us­ing this method to check limit control, it can be established
that limit is functioning properly and will operate if there
is a restricted return--air supply or motor failure. If limit
control does not function during this test, cause must be
determined and corrected.

a. Run furnace for at least 5 minutes.

b. Gradually block off return air with a piece of cardboard

or sheet metal until the limit trips.

c. Unblock return air to permit normal circulation.

d. Burners will re--light when furnace cools down.

2. Check draft safeguard switch.
The purpose of this control is to cause the safe shutdown
of the furnace during certain blocked vent conditions.

a. Verify vent pipe is cool to the touch.

b. Disconnect power tofurnaceand remove vent connector

from furnace vent elbow.

c. Restore power to furnace and setroom thermostat above

room temperature.

d. After normal start--up, allow furnace to operate for 2

minutes, then block vent elbow in furnace 80% of vent
area with a piece of flat sheet metal.

e. Furnaceshouldcycleoffwithin 2 minutes.Ifgas doesnot

shut off within 2 minutes, determine reason draft safe-

SETUP SWITCH

S W --- 2

SETUP SWITCH

S W --- 3

guardswitch did notfunctionproperlyand correct condi­tion.

f. Remove blockage from furnace vent elbow.
g. Switch will auto--reset when it cools.
h. Re--install vent connector.

NOTE: Should switch remain open longer than 3 minutes,
furnace control board will lockout the furnace for 3 hours. To
reset furnace control board, turn thermostat below room
temperature or from HEAT to OFF and turn 115--v power OFF,
then back ON.

3. Check Pressure Switch(es)
This control proves operation of the draft inducer blower.

a. Turn off 115--v power to furnace.
b. Disconnect inducer motor lead wires from wire harness.
c. Turn on 115--v power to furnace.
d. Set thermostat to “call for heat”and wait 1 minute. When

pressure switch is functioning properly, hot surface ig­niter should NOT glow and control diagnostic light
flashesa statuscode32. Ifhot surfaceigniterglowswhen
inducermotoris disconnected, shut down furnaceimme­diately.

e. Determinereason pressure switch did not function prop-

erly and correct condition.

f. Turn off 115--v power to furnace.

g. Reconnect inducer motor wires, replace outer door, and

turn on 115--v power.

h. Blower will run for 90 secondsbeforebeginning the call

for heat again.

i. Furnace should ignite normally.

Step 5 — Checklist

1. Put away tools and instruments. Clean up debris.

2. Verify that switches for LHT and OFF--DELAY are
blower OFF--DELAY are selected as desired.

3. Verify that blower and burner access doors are properly in­stalled.

4. Cycle test furnace with room thermostat.

5. Check operation of accessories per manufacturerfs in­structions.

6. Review User’s Guide with owner.

7. Attach literature packet to

furnace.

312AAV

39

Table 15 – Orifice Size* and Manifold Pressures (In. W.C.) for Gas Input Rate

312AAV

40

A10184

Table 15 -- Orifice Size and Manifold Pressures (In. W.C.) for Gas Input Rate (cont.)

312AAV

A10184A

41

Table 16 – Orifice Size* and Manifold Pressures (In. W.C.) for Gas Input Rate

312AAV

42

A10185

Table 16 -- Orifice Size* and Manifold Pressures (In. W.C.) for Gas Input Rate (cont.)

312AAV

A10185A

43

SERVICE AND MAINTENANCE

PROCEDURES

!

WARNING

FIRE, PERSONAL INJURY AND UNIT DAMAGE
HAZARD

Failure to follow this warning could result in personal injury,
death and/or property damage.

The ability to properly perform maintenance on this
equipment requires certain knowledge, mechanical skills,
tools, and equipment. If you do not possess these, do not
attempt to perform any maintenance on this equipment other
than those procedures recommended in the User’s Manual.

!

WARNING

312AAV

ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD

Failure to follow this warning could result in personal injury
or death.

Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position and
install a lockout tag. There may be more than one
disconnect switch. Lock out and tag switch with a suitable
warning label. Verify proper operation after servicing.

!

UNIT OPERATION HAZARD

Failure to follow this caution may result in improper unit
operation or failure of unit components.

Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and dangerous
operation.

!

ENVIRONMENTAL HAZARD

Failure to follow this caution may result in environmental
pollution.

Remove and recycle all components or materials (i.e. oil,
refrigerant, control board, etc.) before unit final disposal.

Step 1 — Introduction

GENERAL

These instructions are written as if the furnace is installed in an
upflow application. An upflow furnace application is where the
blower is located below the combustion and controls section of
the furnace, and conditioned air is discharged upward. Since this
furnace can be installed in any of the 4 positions shown in Fig. 4,
you must revise your orientation to component location
accordingly.

CAUTION

CAUTION

ELECTRICAL CONTROLS AND

!

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal
injury or death.

There may be more than one electrical supply to the
furnace. Check accessories and cooling unit for additional
electrical supplies that must be shut off during furnace
servicing. Lock out an tag switch with a suitable warning
label.

The electrical ground and polarity for 115--v wiring must be
properly maintained. Refer to Fig. 23 for field wiring information
and to Fig. 52 for furnace wiring information.

NOTE: If the polarity is not correct, the STATUS LED on the
control will flash rapidly and prevent the furnace from heating.
The control system also requires an earth ground for proper
operation of the control and flame--sensing electrode.

The 24--v circuit contains an automotive--type, 3--amp. fuse
located on the control. (See Fig. 31.) Any shorts of the 24--v
wiring during installation, service, or maintenance will cause this
fuse to blow. If fuse replacement is required, use ONLY a 3--amp.
fuse. The control LED will display status code 24 when fuse
needs to be replaced.

Proper instrumentation is required to service electrical controls.
The control in this furnace is equipped with a Status Code LED
(Light--Emitting Diode) to aid in installation, servicing, and
troubleshooting. Status codes can be viewed at the sight glass in
blower access door. The furnace control LED is either ON
continuously, rapid flashing, or a code composed of 2 digits. The
first digit is the number of short flashes, the second digit is the
number of long flashes.

For an explanation of status codes, refer to service label located
on blower access door or Fig. 51, and the troubleshooting guide
which can be obtained from your distributor.

See Fig. 56 for a brief Troubleshooting guide.

For Controls with an Amber

The stored status codes will NOT be erased from the control
memory, if 115-- or 24--v power is interrupted. The control will
store up to five (5) status codes.

1. To retrieve status codes, proceed with the following:

NOTE: NO thermostat signal may be present at control, and all
blower--OFF delays must be completed.

a. Leave 115--v power to furnace turned on.
b. Remove outer access door.
c. Look into blower access doorsightglassfor currentLED

status.

d. BRIEFLY remove insulated terminal wire from thedraft

safeguard (DSS) switch until LED goes out, then recon­nect it.

NOTE: If wire to DSS is disconnected longer than 4 sec, main
blower starts, and retrieval request is ignored.

2. When above items have been completed, the LED flashes
status code 4 times. Record this status code for further
troubleshooting. After the LED flashes status code four
times, BRIEFLY remove wire again from DSS switch un­til LED goes out, then reconnect it to retrieve previous
status code (if available). Repeat as needed for more previ­ous status codes or until Code 11 appears.

WIRING

LED

44

If stat us code recall is needed, briefl y remove then reconnect one main limit wire to di splay last st ored status code. On RED LED boards do not remove power or blower door bef ore initi ating status co de recall.

EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH T HE FIRST DIGI T DETERMINED BY THE NUMBER OF SHORT FLASHES AND THE SECOND DIGI T BY THE NUMBER OF LONG FLASHES.

11 NO PREVIOUS CODE - Stored status c ode is erased automatically after 72 hours.

On RED LED boards stored status codes can also be erased when power
(115 VAC or 24 VAC) to control is interrupted.

12 BLOWER ON AFTER POWER UP (115 VAC or 24 VAC) -Blower runs for the

selected blower off-delay time, if unit is powered up during a call for heat
(R-W/W1 closed) or (R-W/W1) opens during blower on-delay.

13 LIMIT CIRCUIT LOCKOUT - Lockout occurs if a limit, draft safeguard, flame rollout,

or blocked vent switch (if used) is open longer than 3 minutes.

- Control will auto reset after three hours. - Refer to #33.

14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.
21 GAS HEATING LOCKOUT - Control will NOT auto reset.

Check for: - Mis-wired gas v alve - Defective control (valve relay)

22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is de-

energized. Inducer will run until fault is cleared. Check for:

- Leaky gas valve - Stuck-open gas valve

23 PRESSURE SWITCH DID NOT OPEN Check for: - Obstructed pressure tubing

24 SECONDARY VOLTAGE FUSE IS OPEN Check for: - Short circuit in secondary

voltage (24VAC) wiring.

31 HIGH-HEAT PRESSURE SWITCH OR RELAY DID NOT CLOSE OR REOPENED

Control relay may be defective, ref er to status code #32

COMPONENT TEST

To initiate the component test sequence, shut OFF the room thermostat or disconnect the
"R" thermostat lead. Briefly short the TEST/TWIN terminal to the "Com 24V" terminal.
Status LED will flash last status code and then turn ON the inducer motor. The inducer
motor will start in HIGH speed and remain on HIGH speed until the end of the test then
shift to LOW speed for 7 to 15 seconds. The hot s urface igniter, blower motor LO HEAT
speed, blower motor HI HEAT speed, and blower motor COOL speed will be turned ON for
10-15 seconds each. Gas Valve and Humidifier will not be turned on. When the blower is
turned OFF the inducer will be switched to low-speed for 10 seconds.

LED CODE

CONTINUOUS OFF - Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and SEC-2.
CONTINUOUS ON - Control has 24VAC power.
RAPID FLASHING - Line voltage (115VAC) polarity reversed. If twinned, refer to twinning kit instructions.

- Pressure switch stuck closed

STATUS

32 LOW-HEAT PRESSURE SWITCH DID NOT CLOSE OR REOPENED - If open longer than

five minutes, inducer shuts off for 15 minutes before retry. If opens during blower on-delay
period, blower will come on for the selected blower off-delay. Check for:

- Excessive wind - Restricted vent - Defective inducer motor

- Proper vent sizing - Defective pressure switch - Low inducer voltage (115 VAC)

- Inadequate combustion air supply - Low inlet gas pressure (if LGPS u sed)

- Disconnected or obstructed pressure tubing

33 LIMIT CIRCUIT FAULT - I ndicates a limit, draft safeguard, flame rollout, or blocked vent

switch (if used) is open. Blower will r un for 4 minutes or until open switch remakes
whichever is longer. If open longer th an 3 minutes, code changes to lockout #13. If open
less than 3 minutes status code #33 continues to flash until blower shuts off. Flame rollout
switch and BVSS require manual reset. Check for: - Dirty filter or restricted duct system

- Defective blower motor or capacitor - Proper vent sizing - Restricted vent

- Defective switch or connections - Loose blower wheel - Excessive wind

- Inadequate combustion air supply (Flame Roll-out Switch open).

34 IGNITION PROVING FAILURE - Control will try three more times before lockout #14 occurs.

If flame signal lost during blower on-delay period, blower will come on for the selected
blower off-delay. Check for: - Oxide buildup on flame sensor (clean with fine steel wool)

- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal)

- Manual valve shut-off - Control ground continuity

- Gas valve defective or gas valve turned off - Low inlet gas pressure

- Inadequate flame carryover or rough ignition - Defective Hot Surface Ignitor

- Flame sensor must not be grounded

- Green/Yellow wire MUST be connected to furnace sheet metal

43 LOW-HEAT PRESSURE SWITCH OPEN WHILE HIGH-HEAT PRESSURE SWITCH IS

CLOSED - Check for: - Disconnected or obstructed pressure tubing

- Mis-wired pressure switches - Low-heat pressure switch stuck open

- Low inlet gas pressure (if LGPS used)

45 CONTROL CIRCUITRY LOCKOUT Auto-reset after one hour lockout due to;

- Gas valve relay stuck open - Flame sense circuit failure - Software check error
Reset power to clear lockout. Replace control if status code repeats.

Fig. 51 -- Service Label

327598-101 REV. C

Step 2 — Care and Maintenance

!

WARNING

!

SERVICE

WARNING

FIRE OR EXPLOSION HAZARD

Failure to follow this warning could result in personal
injury, death and/or property damage.

Never store anything on, near, or in contact with the
furnace, such as:

1. Spray or aerosol cans, rags, brooms, dust mops,
vacuum cleaners, or other cleaning tools.

2. Soap powders, bleaches, waxes or other cleaning
compounds, plastic or plastic containers, gasoline,
kerosene, cigarette lighter fluid, dry cleaning fluids,
or other volatile fluids.

3. Paint thinners and other painting compounds, paper
bags, or other paper products. Exposure to these
materials could lead to corrosion of the heat
exchanger.

CARBON MONOXIDE POISONING AND FIRE
HAZARD

Failure to follow this warning could result in personal
injury, death, and/or property damage.

Never operate unit without a filter or with filter access door
removed.

!

CAUTION

CUT HAZARD

Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care

and wear appropriate protective clothing, safety glasses and
gloves when handling parts and servicing furnaces.

312AAV

A04210

For continuing high performance and to minimize possible
furnace failure, periodic maintenance must be performed on this
furnace. Consult your local dealer about proper frequency of
maintenance and the availability of a maintenance contract.

!

WARNING

ELECTRICAL SHOCK AND FIRE HAZARD

Failure to follow this warning could result in personal
injury, death or property damage.

Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position and
install a lockout tag. There may be more than one
disconnect switch. Lockout and tag switch with a suitable
warning label.

The minimum maintenance on this furnace is as follows:

1. Check and clean air filter each month or more frequently if
required. Replace if torn.

2. Check blower motor and wheel for cleanliness each heat­ing and cooling season. Clean as necessary.

3. Check electrical connections for tightness and controls for
proper operation each heating season. Service as neces­sary.

4. Inspect burner compartment before each heating season
for rust, corrosion, soot or excessive dust. If necessary,
have furnace and burner serviced by a qualified service
agency.

5. Inspect the vent pipe/vent system before each heating sea­son for rust, corrosion, water leakage, sagging pipes or
broken fittings. Have vent pipes/vent system serviced by a
qualified service agency.

6. Inspect any accessories attached to the furnace such as a
humidifier or electronic air cleaner. Perform any service or
maintenance to the accessories as recommended in the ac­cessory instructions.

45

312AAV

Fig. 52 -- Wiring Diagram

46

A07125

Table 17 – Filter Size Information (In. / Mm)

FURNACE CASING WIDTH

14---1/2 (368)

17---1/2 (445)

21 (533)

24 (610)

* Recommended
** Some furnaces may have 2 filters.

RETURN

16 x25 x 3/4

(406 x635 x 19)

16 x25 x 3/4

(406 x635 x 19)

16 x25 x 3/4

(406 x635 x 19)

16 x25 x 3/4

(406 x635 x 19)

CLEANING AND/OR REPLACING AIR FILTER

The air filter arrangement will vary depending on the application.
NOTE: If the filter has an airflow direction arrow, the arrow

must point towards the blower.

!

CAUTION

CUT HAZARD

Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care

and wear appropriate protective clothing, safety glasses and
gloves when handling parts and servicing furnaces.

Accessory media cabinet filter procedures:

1. Turn off electrical supply to furnace before removing filter
access door.

2. Remove filter cabinet door.

3. Slide filter out of cabinet.

4. If equipped with permanent, washable 3/4--in. (19 mm) fil­ter, clean filter by spraying cold tap water through filter in
opposite direction of airflow. Rinse filter and let dry. Oil­ing or coating of the filter is not recommended. See Table
17 for size information.

5. If equipped with factory--specified disposable media filter,
replace only with media filter having the same part num­ber and size. For expandable replacement media, refer to
the instructions included with the replacement media.

6. Slide filter into cabinet.

7. Replace filter cabinet door.

8. Turn on electrical supply to furnace.

BLOWER MOTOR AND

!

WHEEL

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal
injury or death.

Blower access door switch opens 115--v power to control.
No component operation can occur unless switch is closed.
Caution must be taken when manually closing this switch
for service purposes.

NOTE: The blower wheel should not be dropped or bent as
balance will be affected.

The following steps should be performed by a qualified
service agency.

To ensure long life and high efficiency, clean accumulated dirt
and grease from blower wheel and motor annually.

FILTER SIZE

BOTTOM

RETURN

14 x25 x 3/4

(356 x635 x 19)

16 x25 x 3/4

(406 x635 x 19)

20 x25 x 3/4

(508 x635 x 19)

24 x25 x 3/4

(610 x635 x 19)

FILTER TYPESIDE

Wash abl e*

Wash abl e*

Wash abl e*

Wash abl e*

The inducer and blower motors are pre--lubricated and require no
additional lubrication. These motors can be identified by the
absence of oil ports on each end of the motor.

Clean blower motor and wheel as follows:

1. Turn off electrical supply to furnace.

2. Remove outer door.

3. For downflow or horizontal furnaces having vent pipes
within the furnace that pass in front of the blower access
door:

a. Disconnect vent connector from furnace vent elbow.
b. Disconnect and remove short piece of vent pipe from

within furnace.

4. Remove 2 screws from blower access door and remove
blower access door.

5. All factory wires can be left connected, but field thermo­stat connections may need to be disconnected depending
on their length and routing.

6. Remove 2 screws holding blower assembly to blower
deck and slide blower assembly out of furnace.

7. Clean blower wheel and motor using a vacuum with soft
brush attachment. Blower wheel blades may be cleaned
with a small paint or flux brush. Do not remove or disturb
balance weights (clips) on blower wheel blades.

8. Vacuum any loose dust from blower housing, wheel and
motor.

9. If a greasy residue is present on blower wheel, remove
wheel from the blower housing and wash it with an appro­priate degreaser. To remove wheel:

NOTE: Before disassembly, mark blower mounting arms, motor,
and blower housing so motor and each arm is positioned at the
same location during reassembly.

a. Disconnectcapacitorwires(ifequipped)and groundwire

attached to blower housing.

b. Remove screws securing cutoff plate and remove cutoff

plate from housing.

c. Loosen set screw holding blower wheel on motor shaft

(160+/--20 in.--lb. when reassembling).

d. Removebolts holding motor to blowerhousing and slide

motorout of wheel(40+/--10 in.--lb. when reassembling).

e. Remove blower wheel from housing.

f. Clean wheel and housing.

10. Reassemble motor and blower by reversing steps 9a,
through 9e. Be sure to reattach ground wire to the blower
housing.

11. Verify that blower wheel is centered in blower housing
and set screw contacts the flat portion of the motor shaft.
Loosen set screw on blower wheel and reposition if neces­sary.

12. Spin the blower wheel by hand to verify that the wheel
does not rub on the housing.

13. Reinstall blower assembly in furnace.

312AAV

47

!

UNIT DAMAGE HAZARD

Failure to follow this caution may result in shortened heat
exchanger life.

Heating fan speed(s) MUST be adjusted to provide proper
air temperature rise as specified on the rating plate.
Recommended operation is at the midpoint of the rise range
or slightly above. Refer to “SET TEMPERATURE RISE”
under START--UP, ADJUSTMENT, and SAFETY
CHECK.

14. Reinstall 2 screws securing blower assembly to blower
deck.

15. Refer to furnace wiring diagram, and connect thermostat
leads if previously disconnected.

16. To check blower for proper rotation:

312AAV

a. Turn on electrical supply.

b. Manually close blower access door switch.

NOTE: If thermostat terminals are jumpered at the time blower
access door switch is closed, blower will run for 90 sec before
beginning a heating or cooling cycle.

c. Perform component self--test as shown at the bottom of

the SERVICE label, located on the front ofblower access
door.

d. Verify blower is rotating in the correct direction.

17. If furnace is operating properly, RELEASE BLOWER
ACCESS DOOR SWITCH. Remove any jumpers or re­connect any disconnected thermostat leads. Replace
blower access door.

!

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal
injury, or death.

Blower access door switch opens 115--v power to furnace
control. No component operation can occur unless switch is
closed. Exercise caution to avoid electrical shock from
exposed electrical components when manually closing this
switch for service purposes.

CAUTION

WARNING

problem exists which needs to be corrected, such as improper
adjustment of manifold pressure, insufficient or poor quality
combustion air, incorrect size or damaged manifold orifice(s),
improper gas, or a restricted heat exchanger. Action must be taken
to correct the problem.

If it becomes necessary to clean the heat exchangers because of
dust or corrosion, proceed as follows:

1. Turn OFF gas and electrical power to furnace.

2. Remove outer access door.

3. Disconnect vent connector from furnace vent elbow.

4. For downflow or horizontal furnace having an internal
vent pipe, remove internal vent pipe within the casing.

5. Disconnect wires to the following components. Mark
wires to aid in reconnection of (be careful when discon­necting wires from switches because damage may occur):

a. Draft safeguard switch.
b. Inducer motor.
c. Pressure switches.
d. Limit overtemperature switch.
e. Gas valve.

f. Hot surface igniter.
g. Flame--sensing electrode
h. Flame rollout switches.

6. Remove screws that fasten the collector box assembly to
the cell panel. Be careful not to damage the collector box.
Inducer assembly and elbow need not be removed from
collector box.

7. Disconnect gas line from gas manifold.

8. Remove the 5 screws that attach the burner assembly to
the cell panel. The gas valve and individual burners need
not be removed from support assembly. Remove NOx
baffles if installed.

NOTE: Be very careful when removing burner assembly to
avoid breaking igniter. See Fig. 53 and 54 for correct igniter
location.

18. Downflow or horizontal furnaces with vent pipe through
furnace only:

a. Installandconnectshortpieceof ventpipeinsidefurnace

to existing vent.

b. Connect vent connector to vent elbow.

19. Reinstall outer door.

20. Turn on gas supply and cycle furnace through one com­plete heating and cooling cycle. Verify the furnace temper­ature rise as shown in Adjustments Section. Adjust tem­perature rise as shown in Adjustments Section. If outdoor
temperature is below 70_F(21_C) turn off circuit breaker
to outdoor unit before running furnace in the cooling
cycle. Turn outdoor circuit breaker on after completing
cooling cycle.

CLEANING HEAT
The following steps should be performed by a qualified

service agency:
NOTE: If the heat exchangers get a heavy accumulation of soot

and carbon, they should be replaced rather than trying to clean
them thoroughly. A build--up of soot and carbon indicates that a

EXCHANGER

A05025

Fig. 53 -- Igniter Position--Side View

9. Using field--provided 25--caliber rifle cleaning brush,
36--in. (914 mm) long 1/4--in. (6 mm) diameter steel
spring cable, a variable speed, reversible electric drill, and
vacuum cleaner, clean cells as follows:

a. Remove metal screw fitting from wire brush to allow in-

sertion into cable.

b. Insert the twisted wire end of brush into end of spring

cable, and crimp tight with crimping tool or crimp by

48

strikingwith ball--peenhammer. TIGHTNESSIS VERY
IMPORTANT.

NOTE: The materials needed in item 9 can usually be purchased
at local hardware stores.

(1.) Attach variable--speed, reversible drill to the end of

spring cable (end opposite brush).

(2.) Insert brush end of cable into the outlet opening of

cell and slowly rotate with drill. DO NOT force
cable. Gradually insert cableinto upper pass ofcell.
(See Fig. 55.)

(3.) Work cable in and out of cell 3 or 4 times to obtain

sufficient cleaning. DO NOT pull cable with great
force. Reverse drill and gradually work cable out.

(4.) Insert brush end of cable in burner inlet opening of

cell, and proceed to clean 2 lower passes of cell in
same manner as upper pass.

(5.) Repeat foregoing procedures until each cell in fur-

nace has been cleaned.

(6.) Using vacuum cleaner, remove residue from each

cell.

(7.) Using vacuum cleaner with soft brush attachment,

clean burner assembly.
(8.) Clean flame sensor with fine steel wool.
(9.) Install NOx baffles (if removed.)

(10.) Reinstall burner assembly. Center burners in cell

openings.

10. Remove old sealant from cell panel and collector box
flange.

11. Spray releasing agent on the heat exchanger cell panel
where collector box assembly contacts cell panel.

NOTE: A releasing agent such as cooking spray or equivalent
(must not contain corn or canola oil, aromatic or halogenated
hydrocarbons or inadequate seal may occur) and RTV sealant
(G.E. 162, 6702, or Dow--Corning 738) are needed before
starting installation. DO NOT substitute any other type of RTV
sealant. G.E. 162 (P771--9003) is available through RCD in 3--oz.
tubes.

12. Apply new sealant to flange of collector box and attach to
cell panel using existing screws, making sure all screws
are secure.

13. Reconnect wires to the following components (Use con­nection diagram on wiring label, if wires were not marked
for reconnection locations.):

a. Draft safeguard switch.

b. Inducer motor.

c. Pressure switches.

d. Limit overtemperature switch.

e. Gas valve.

f. Hot surface igniter.
g. Flame--sensing electrode.
h. Flame rollout switches.

14. Reinstall internal vent pipe, if applicable.

15. Reinstall vent connector on furnace vent elbow. Securely
fasten vent connector to vent elbow with 2 field--supplied,
corrosion--resistant, sheet metal screws located 180_ apart.

1-7/8

(47.6 mm)

A05026

Fig. 54 -- Igniter Position--Top View

A91252

Fig. 55 -- Cleaning Heat Exchanger Cell

16. Replace blower access door only, if it was removed.

17. Set thermostat above room temperature and check furnace
for proper operation.

18. Verify blower airflow and speed changes between heating
and cooling.

!

WARNING

FIRE OR EXPLOSION HAZARD

Failure to follow this warning could result in personal
injury death and/or property damage.

Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically for
the detection of leaks to check all connects.

19. Check for gas leaks.

20. Replace outer access door.

Step 3 — Sequence of Operation

NOTE: Furnace control must be grounded for proper operation

or control will lockout. Control is grounded through green wire
connected to gas valve and burner bracket screw. Using the
schematic diagram in Fig. 52, follow the sequence of operation
through the different modes. Read and follow the wiring diagram
very carefully.

NOTE: If a power interruption occurs during a call for heat
(W/W1 or W/W1--and--W2), the control run the blower for the
selected blower off--delay period two seconds after power is
restored and if the thermostat is still calling for gas heating. The
LED light will flash code 12 during this period, after which the
LED will be ON continuous, as long as no faults are detected.
After this period, the furnace will respond to the thermostat
normally.

The blower door must be installed for power to be conducted
through the blower door interlock switch ILK to the furnace

312AAV

49

control CPU, transformer TRAN, inducer motor IDM, blower
motor BLWM, hot--surface igniter HSI, and gas valve GV.

1. Two--Stage Heating (Adaptive mode) with Single--

Stage Thermostat

(See Fig. 23 or 32 for thermostat connections)

NOTE: The low--heat only switch (LHT) selects either the
low--heat only operation mode when ON, (see item 2. below) or
the adaptive heating mode when OFF in response to a call for
heat. (See Fig. 33.) When the W2 thermostat terminal is energized
it will always cause high--heat operation when the R to W circuit
is closed, regardless of the setting of the low--heat only switch.
This furnace can operate as a two--stage furnace with a
single--stage thermostat because the furnace control CPU includes
a programmed adaptive sequence of controlled operation, which
selects low--heat or high--heat operation. This selection is based
upon the stored history of the length of previous gas--heating
periods of the single--stage thermostat.

The furnace will start up in either low-- or high--heat. If the
furnace starts up in low--heat, the control CPU determines the
low--heat on--time (from 0 to 16 minutes) which is permitted

312AAV

before switching to high--heat.
If the power is interrupted, the stored history is erased and the

control CPU will select low--heat for up to 16 minutes and then
switch to high--heat, as long as the thermostat continues to call for
heat. Subsequent selection is based on stored history of the
thermostat cycle times.

The wall thermostat “calls for heat”, closing the R to W circuit.
The furnace control performs a self--check, verifies the low--heat
and high--heat pressure switch contacts LPS and HPS are open,
and starts the inducer motor IDM in high--speed.

a. Inducer Prepurge Period

(1.) If the furnace control CPU selects low--heat opera-

tion the inducer motor IDM comes up to speed, the
low--heat pressure switch LPS closes, and the fur­nace control CPU begins a 15--second prepurge
period.Afterthe low--heatpressureswitchre--closes
thefurnacecontrolCPUwillbegina15--secondpre­purgeperiod,and continue to runthe inducer motor
IDM at high--speed.

(2.) If the furnace control CPU selects high--heat opera-

tion, the inducer motor IDM remains running at
high--speed, and thehigh--heatpressure switch relay
HPSR is de--energized to close the NC contact.
When sufficient pressureis available the high--heat
pressure switch HPS closes, and the high--heat gas
valve solenoid GV--HI is energized. The furnace
control CPU begins a 15--second prepurge period
after the low--heat pressure switch LPS closes. Ifthe
high--heatpressureswitch HPS failsto closeand the
low--heat pressure switch LPS closes, the furnace
will operateat low--heat gas flowrate until the high-­heat pressure switch closes for a maximum of 2
minutes after ignition.

b. Igniter Warm--Up--At the end of the prepurge period,

the (Hot Surface Igniter) HSI is energized for a
17--second igniter warm--up period.

c. Trial--for--Ignition Sequence--When the igniter warm--

up period is completed the main gas valve relay contacts
GVR--1 and --2 close to energize the gas valve solenoid
GV--M,thegasvalveopens,and 24 vacpowerissupplied
for a field--installed humidifier at the HUM terminal.The
gasvalvesolenoid GV--M permitsgasflowto the burners
where it is ignited by the HSI. Five sec after the GVR
closes,a 2--sec flame proving period begins.The HSIig­niter willremain energized until the flame issensed orun­til the 2--sec flame proving period begins. If the furnace

control CPU selects high--heat operation, the high--heat
gas valve solenoid GV--HI is also energized.

d. Flame--Proving--When the burner flame is proved at the

flame--proving sensor electrode FSE, the inducer motor
IDM switches to low--speed unless running at high-­speed, and the furnace control CPU begins the blower-­ON delayperiodand continuestohold thegasvalveGV-­M open. If the burner flame is not proved within two
seconds,thecontrolCPU will closethegas valve GV--M,
and the control CPU will repeat theignition sequence for
up to three more Trials--For--Ignition before going to Ig­nition-- Lockout. Lockout will be reset automatically
after three hours, by momentarily interrupting 115 vac
power to the furnace, or by interrupting 24 vac power at
SEC1 or SEC2tothe furnacecontrolCPU (not at W/W1,
G, R, etc.). If flame is proved when flame should not be
present, the furnace control CPU will lock out of Gas-­Heating mode and operate the inducer motor IDM on
high speed until flame is no longer proved.

e. Blower--ON Delay--If the burner flame is proven the

blower--ON delay for low--heat and high--heat are asfol­lows:
Low--Heat--45 seconds after the gas valve GV--M is en­ergized the blower motor (BLWM) is energized at LO
HEAT speed.
High--Heat--25 secondsafterthe gas valve GV--M isen­ergized the BLWM is energized at HI HEAT speed. Sim­ultaneously, the electronic air cleaner (EAC--1) terminal
is energized and remains energized aslong as the BLWM
is energized.

f. SwitchingfromLow--to High--Heat--Ifthe furnacecon-

trol CPU switches from low--heat to high--heat, the fur­nace control CPU will switch the inducer motor IDM
speed from low to high. The high--heat pressure switch
relay HPSR is de--energized to close the NC contact.
When sufficient pressureis available the high--heat pres­sure switch HPS closes, and the high--heat gas valve
solenoid GV--HI is energized. The blower motor BLWM
will switch to HI HEAT speed five seconds after the fur­nace control CPU switches from low--heat to high--heat.

g. Switching from High-- to Low--Heat--The furnace con-

trol CPU will not switch from high--heat to low--heat
while thethermostat R--to--Wcircuit isclosed when using
a single stage thermostat.

h. Blower--OFF Delay--When thethermostatis satisfied,the

R to W circuit is opened, de--energizing the gas valve
GV--M,stoppinggas flowto the burners,andde--energiz­ing the humidifier terminal HUM. The inducer motor
IDM will remain energized for a 5--second post--purge
period.The blower motorBLWM andair cleanertermin­al EAC--1 willremainenergized for 90,120, 150,or 180
seconds (depending on selection at blower--OFF delay
switches). The furnace control CPU is factory--set for a
120--second blower--OFF delay.

2. Two--Stage Thermostat and Two--Stage Heating (See Fig.
31 for thermostat connections)

NOTE: In this mode the LHT must be ON to select the low--heat
only operation mode in response to closing the thermostat
R--to--W1 circuit. Closing the thermostat R--to--W1--and--W2
circuits always causes high--heat operation, regardless of the
setting of the low--heat--only switch.

The wall thermostat “calls for heat”, closing the R--to--W1 circuit
for low--heat or closing the R--to--W1 and--W2 circuits for
high--heat. The furnace control performs a self--check, verifies the
low--heat and high--heat pressure switch contacts LPS and HPS
are open, and starts the inducer motor IDM in high--speed.

50

The start up and shut down functions and delays described in
item 1. above apply to the 2--stage heating mode as well, except
for switching from low-- to high--Heat and vice versa.

a. Switching from Low-- to High--Heat--If the thermostat

R--to-- W1 circuit is closed and the R--to--W2 circuit
closes, the furnace control CPU will switch the inducer
motor IDM speed from low to high.The high--heat pres­sure switch relay HPSR is de--energized to close the NC
contact. When sufficient pressure is available the high-­heat pressure switch HPS closes, and the high--heat gas
valve solenoid GV--HI is energized. The blower motor
BLWM will switch to HIHEAT speed five seconds after
the R--to--W2 circuit closes.

b. Switching from High-- to Low--Heat--If the thermostat

R--to--W2circuitopens,and theR--to--W1 circuitremains
closed, the furnace control CPU will switch the inducer
motor IDM speed from high to low. The high--heat pres­sure switch relay HPSR is energized to open the NC con­tact and de--energize the high--heat gas valve solenoid
GV--HI. When the inducer motor IDM reduces pressure
sufficiently, the high--heat pressure switch HPS will
open. The gas valve solenoid GV--M will remain ener­gized as long as the low--heat pressure switch LPS re­mains closed. The blower motor BLWM will switch to
LO HEAT speed five seconds after the R--to--W2 circuit
opens.

3. Cooling Mode--The thermostat “calls for cooling.”
a. Single--Speed Cooling--

(See Fig. 27 for thermostat connections)
The thermostat closes the R--to--G--and--Y circuits. The
R--to-- Y circuit starts the outdoor unit, and the R--to-­G--and--Y/Y2 circuits start the furnace blower motor
BLWM on COOL speed.
The electronic air cleaner terminal EAC--1 is energized
with 115vac when theblower motor BLWM isoperating.

When the thermostat is satisfied, the R--to--G and--Y cir­cuitsare opened. Theoutdoor unit will stop, and thefur­naceblowermotor BLWMwillcontinueoperating on the
COOL speed for an additional 90 seconds. Jumper Y/Y2
to DHUM to reduce the cooling off--delay to 5 seconds.
(See Fig. 24.)

b. Single--Stage Thermostat and Two--Speed Cooling

(Adaptive Mode)

(See Fig. 32 for thermostat connections)
This furnace can operate a two--speed cooling unit with
a single--stage thermostat because the furnace control
CPU includes a programmed adaptive sequence of con­trolled operation, which selects low--cooling or high-­coolingoperation.Thisselectionisbasedupon thestored
history of the length of previous cooling period of the
single--stage thermostat.

NOTE: The air conditioning relay disable jumper ACRDJ must
be connected to enable the adaptive cooling mode in response to
a call for cooling. (See Fig. 33.) When ACRDJ is in place, the
furnace control CPU can turn on the air conditioning relay ACR
to energize the Y/Y2 terminal and switch the outdoor unit to
high--cooling.

The furnace control CPU can start up the cooling unit in either
low-- or high--cooling. If starting up in low--cooling, the furnace
control CPU determines the low--cooling on--time (from 0 to 20
minutes) which is permitted before switching to high--cooling. If
the power is interrupted, the stored history is erased and the
furnace control CPU will select low--cooling for up to 20 minutes
and then energize the air conditioning relay ACR to energize the
Y/Y2 terminal and switch the outdoor unit to high--cooling, as
long as the thermostat continues to call for cooling. Subsequent
selection is based on stored history of the thermostat cycle times.

The wall thermostat “calls for cooling”, closing the
R--to--G--and--Y circuits. The R--to--Y1 circuit starts the outdoor
unit on low--cooling speed, and the R--to--G--and--Y1 circuits
starts the furnace blower motor BLWM at low--cool speed (same
speed as LO HEAT).
If the furnace control CPU switches from low--cooling to
high--cooling, the furnace control CPU will energize the air
conditioning relay ACR. When the air conditioning relay ACR is
energized the R--to--Y1--and--Y2 circuits switch the outdoor unit
to high--cooling speed, and the R--to--G--and--Y1--and--Y/Y2
circuits switch the furnace blower motor BLWM to COOL speed.

NOTE: When transitioning from low--cooling to high--cooling
the outdoor unit compressor will shut down for 1 minute while
the BLWM continues to run at low--cool speed (same speed as
LO--HEAT) until the outdoor unit compressor comes back on at
high speed.

The electronic air cleaner terminal EAC--1 is energized with 115
vac whenever the blower motor BLWM is operating. When the
thermostat is satisfied, the R--to--G--and--Y circuit are opened.
The outdoor unit stops, and the furnace blower BLWM and
electronic air cleaner terminal EAC--1 will remain energized for
an additional 90 seconds. Jumper Y1 to DHUM to reduce the
cooling off--delay to 5 seconds. (See .Fig. 34.)

c. Two--Stage Thermostat and Two--Speed Cooling (See

Fig. 31 for thermostat connections)

NOTE: The air conditioning relay disable jumper ACRDJ must
be disconnected to allow thermostat control of the outdoor unit
staging. (See Fig. 33.)

The thermostat closes the R--to--G--and--Y1 circuits for
low--cooling or closes the R--to--G--and--Y1--and--Y2 circuits for
high--cooling. The R--to--Y1 circuit starts the outdoor unit on
low--cooling speed, and the R--to--G--and--Y1 circuit starts the
furnace blower motor BLWM on low--cool speed (same speed as
LO HEAT). The R--to--Y1--and--Y2 circuits start the outdoor unit
on high--cooling speed, and the R--to--G--and-- Y/Y2 circuits start
the furnace blower motor BLWM on COOL speed. The
electronic air cleaner terminal EAC--1 is energized with 115 vac
whenever the blower motor BLWM is operating. When the
thermostat is satisfied, the R--to--G--and--Y1 or
R--to--G--and--Y1--and--Y2 circuits are opened. The outdoor unit
stops, and the furnace blower BLWM and electronic air cleaner
terminal EAC--1 will remain energized for an additional 90
seconds. Jumper Y1 to DHUM to reduce the cooling off--delay to
5 seconds. (See Fig. 33.)

4. Thermidistat Mode

(See Fig. 26 -- 28 for Thermidistat connections) The dehu­midification output, DHUM on the Thermidistat should be
connected to the furnace control thermostat terminal
DHUM. When there is a dehumidify demand, the DHUM
input is activated, which means 24 vac signal is removed
from the DHUM input terminal. In other words, the
DHUM input logic is reversed. The DHUM input is
turned ON when no dehumidify demand exists. Once 24
vac is detected by the furnace control on the DHUM input,
the furnace control operates in Thermidistat mode. If the
DHUM input is low for more than 48 hours, the furnace
control reverts back to non--Thermidistat mode.
The cooling operation described in item 3. above also ap­plies to operation with a Thermidistat. The exceptions are
listed below:

a. Low cooling -- When the R--to--G--and--Y1 circuit is

closedandthereis a demandfor dehumidification,thefur­naceblowermotor BLWMwill continuerunning at low-­cool speed (same speed as LO HEAT).

b. High cooling --When the R--to--G--and--Y/Y2 circuit is

closedandthereis a demandfor dehumidification,thefur­nace blower motor BLWM will drop the blower speed

312AAV

51

from COOL to HI HEAT for a maximum of 10 minutes
before reverting back to COOL speed. If there is still a
demand for dehumidification after 20 minutes, the fur­nacecontrol CPU will drop theblower speed back to HI
HEAT speed. This alternating 10--minute cycle will con­tinue as long as there is a call for cooling.

c. Cooling off--delay -- When the “call for cooling” is satis-

fiedandthereisa demand fordehumidification, the cool­ing blower--off delay is decreased from 90 seconds to 5
seconds.

5. Continuous Blower Mode

When the R--to--G circuit is closed by the thermostat, the
blower motor BLWM will operate on continuous--blower
speed (can be set to LO HEAT, HI HEAT, or COOL
speed). Factory default is LO HEAT speed. Terminal
EAC--1 is energized as long as the blower motor BLWM is
energized. During a call for heat, the blower BLWM will
stop during igniter warm--up (17 seconds), ignition (7
seconds), and blower--ON delay (45 seconds in low--heat,
and 25 seconds in high--heat), allowing the furnace heat

312AAV

exchangers to heat up more quickly, then restarts at the
end of the blower--ON delay period at LO HEAT or HI
HEAT speed respectively. The blower motor BLWM will
revert to continuous--blower speed after the heating cycle
is completed. In high--heat, the furnace control CPU will
hold the blower motor BLWM at HI HEAT speed during
the selected blower--OFF delay period before reverting to
continuous--blower speed.
When the thermostat “calls for low--cooling”, the blower
motor BLWM will switch to operate at low--cool speed
(same speed as LO HEAT). When the thermostat is satis­fied, the blower motor BLWM will operate an additional
90 seconds on low--cool speed before reverting back to
continuous--blower speed.
When the thermostat “calls for high--cooling”, the blower
motor BLWM will operate at COOL speed. When the
thermostat is satisfied, the blower motor BLWM will oper­ate an additional 90 seconds on COOL speed before re­verting back to continuous--blower speed.
When the R--to--G circuit is opened, the blower motor
BLWM will continue operating for an additional 5
seconds, if no other function requires blower motor
BLWM operation.

Continuous Blower Speed Selection from Thermostat

To select different continuous--blower speeds from the
room thermostat, momentarily turn off the FAN switch or
push button on the room thermostat for 1--3 seconds after
the blower motor BLWM is operating. The furnace control
CPU will shift the continuous--blower speed from the fact­ory setting of LO HEAT to HI HEAT speed. Momentarily
turning off the FAN switch again at the thermostat will
shift the continuous--blower speed from HI HEAT to
COOL. Repeating the procedure will shift the continuous-­blower speed from COOL to LO HEAT speed. The selec­tion can be changed as many times as desired and is stored
in the memory to be automatically used following a power
interruption.

NOTE: If the blower--off delay is set to the maximum, the
adjustable continuous--fan feature is locked (i.e., fan speed cannot
be changed from its current setting).

6. Heat Pump
(See Fig. 27--30 for thermostat connections)
When installed with a heat pump, thefurnace control auto­matically changes the timing sequence to avoid long
blower off times during demand defrost cycles. When the
R--to-- W/W1--and--Y1 or R--to--W/W1--and--Y1--and--G
circuits are energized the furnace control CPU will switch
to or turn on the blower motor BLWM at low--cool speed
(same speed as LO HEAT), and begin a low--heat cycle.
The blower motor BLWM will remain on until the end of
the prepurge period, then shut off for 24 seconds then
come back on at LO HEAT speed. When the W/W1 input
signal disappears, the furnace control begins a normal in­ducer post--purge period and the blower remains running
at LO HEAT speed. If the R--to-- W/W1--and--Y1--and--G
signals disappear at the same time, the blower motor
BLWM will remain on for the selected blower-- OFF delay
period. If the R--to--W/W1--and--Y1 signals disappear,
leaving the G signal, the blower motor BLWM will remain
on for the selected blower--OFF delay period then switch
to continuous--blower speed.
When the R--to--W/W1--and--Y/Y2, R--to--W/W1--and-­Y / Y 2 -- a n d -- G , R -- t o -- W / W 1 -- a n d -- Y 1 -- a n d -- Y / Y 2 , o r
R--to--W/W1--and-- Y1--and--Y/Y2--and--G circuits are en­ergized the furnace control CPU will switch to or turn on
the blower motor BLWM at COOL speed, and begin a
high--heat cycle. The blower motor BLWM will remain on
until the end of the prepurge period, then shut off for 24
seconds then come back on at HI HEAT speed. When the
W/W1 input signal disappears, the furnace control begins
a normal inducer post--purge period and the
blower switches to COOL speed after a 3 second delay. If
t h e R -- t o -- W / W 1 -- a n d -- Y / Y 2 -- a n d -- G o r R -- t o -- W / W 1 -- a n d

--Y1--and-- Y/Y2--and--G signals disappear at the same
time, the blower motor BLWM will remain on for the se­lected blower--OFF delay period. If the R--to--W/W1-­a n d -- Y / Y 2 o r R -- t o -- W / W 1 -- a n d -- Y 1 -- a n d -- Y / Y 2 s i g n a l s
disappear, leaving the G signal, the blower motor BLWM
will remain on for the selected blower-- OFF delay period
then switch to continuous--blower speed.

Step 4 — Wiring Diagrams

Refer to wiring diagram, Fig. 52.

Step 5 — Troubleshooting

Refer to the service label. (See Fig. 51—Service Label.) The
Troubleshooting Guide can be a useful tool in isolating furnace
operation problems. Beginning with the word “Start,” answer
each question and follow the appropriate arrow to the next item.

The Guide will help to identify the problem or failed component.
After replacing any component, verify correct operation
sequence.

52

NO

k to START.

Is door switch closed?

NO

Is door switch closed?

NO

YES

Is circuit breaker closed?

NO

Is there 115V going to switch?

NO

YES

breaker to furnace.

Check for continuity in wire from circuit

YES

Replace door switch.

er and go bac

Close circuit break

Replace transformer.

interconnecting cable.

Check room thermostat or

NO

thermostat terminals on the furnace control?

Is 24V present at W/W1, W2, Y1, Y/Y2 or G

NO

Y/Y2, and G (24V) thermostat signals?

Does the control respond to W/W1, W2, Y1,

NO

YES

Disconnect all the thermostat wires from the

YES

Run system through a low-heat, high-heat,

NO

lem repeat when using a

connect the Com24V thermostat terminal to

furnace control. Either install a ballast resistor,

jumper wire?

furnace control.

codes are erased after 72 hours. On RED

or cooling cycle to check operation. Status

Does the prob

YES

Replace furnace control.

erased whenever (115V or 24V) is interrupted.

LED boards stored status codes can also be

The thermostat is not compatible with the

the thermostat, or replace the thermostat.

312AAV

YES

TROUBLESHOOTING GUIDE

Is there 115V at L1 and L2?

NO

YES

START

Is LED status light on?

YES

Is there 24V at SEC-1 and SEC-2?

Replace furnace control.

switched to low-speed for 10 seconds.

not be turned on. When the blower motor is turned OFF the inducer will be

COOL speed will run for 10 – 15 seconds each. Gas valve and humidifier will

component test. The HSI, blower motor LO HEAT speed, HI HEAT speed, and

the control will turn ON at HI HEAT speed. The inducer will run for the entire

4 times, the control will start the component test sequence. Once indicated

long flash) if there was no previous fault. After the control repeats the code

flash the status code of the previous fault or status code #11 (1 short and 1

TEST/TWIN terminal to Com24V terminal until the LED goes out. LED will

You can also recall the previous status code by momentarily shorting the

not remove power or blower access panel before initiating status code recall.

draft safeguard switch to display stored status code. On RED LED control do

To recall status code briefly remove and reconnect one RED wire from the

voltage (24V) transformer phasing.

units are twinned, check for proper low-

Check for correct line voltage polarity. If

NO

NO

mined

YES

f short flashes and the second

digit by the number of long flashes?

by the number o

2 digit number with the first digit deter

with a combination of short and long flashes?

Is LED status light blinking ON/OFF slowly

Determine status code. The status code is a

YES

without a pause?

Is LED status light blinking rapidly

Fig. 56 -- Troubleshooting Guide -- 2--Speed

than #11?

Was there a previous status code other

YES

or the status code that

was flashed.

Go to section below f

A02107A

53

- Flame circuit failure.

reset after 1 hour lockout due to:

45 CONTROL CIRCUITRY LOCKOUT Auto-

- Software check error.

- Gas valve relay stuck open.

Reset power to clear lockout. Replace

control if code repeats.

Replace furnace control.

NO

Replace defective component.

Check for continuity in the harness and igniter.

YES

Check for:

Replace valve.

Check that all gas valves are turned on.

Check connections. If OK, replace control.

NO

ignition.

- Low inlet gas pressure.

- Inadequate flame carryover or rough

NO

- Proper firing rate.

- Blocked or incorrect carry- over gap.

NO

ow blower to come on and repeat test to

(.045” nominal)

check for intermittent operation.

All

YES

If burners operate in high-heat then

sensor location.

If OK, check burner carryover and flame

switch to low-heat, check manifold pressure.

control.

heat. If burners will still not stay on replace

burners will not stay on, repeat check in high-

near typical value (4.0-6.0 nominal) and

Check connections and retry. If current is

NO

NO

Replace furnace control.

Replace electrode.

NO

312AAV

tube.

- Low inlet gas pressure (if LGPS used).

- Miswired pressure switches.

- Disconnected or obstructed pressure

- Low-heat pressure switch stuck open.

SWITCH IS CLOSED - Check for:

WHILE HIGH-HEAT PRESSURE

43 LOW-HEAT PRESSURE SWITCH OPEN

- Low inlet gas pressure (if LGPS used).

- Proper vent sizing.

delay. Check for:

will come on for the selected blower off-

during blower on-delay period, blower

for 15 minutes before retry. If opens

longer than 5 minutes, inducer shuts off

NOT CLOSE OR REOPENED – If open

32 LOW-HEAT PRESSURE SWITCH DID

- Low inducer voltage (115V).

present for the 15 second period?

NEUTRAL-L2 on the control. Was 115V

Check for 115V between pin 1 and

initiate another component test sequence.

Unplug igniter harness from control and

tubing.

- Disconnected or obstructed pressure

- Inadequate combustion air supply.

- Defective inducer motor.

- Excessive wind.

- Defective pressure switch.

- Restricted vent.

valve receive 24V?

across gas valve connections. Does gas

thermostat to call for heat. Connect voltmeter

Reconnect the R thermostat lead and set

ower will run for 4 minutes or until

witch remakes whichever is longer.

Bl

If open longer than 3 minutes, code

open s

open.

blocked vent shutoff switch* (if used) is

limit, draft safeguard, flame rollout, or

33 LIMIT CIRCUIT FAULT – Indicates the

YES

YES

ners ignite?

Does gas valve open and allow gas to flow?

than 3 min. status code #33 continues

changes to lockout #13. If open less

Do the main bur

Flame

.

:

ower shuts off

or

l

k f

ower wheel.

Chec

- Dirty filter or restricted duct system.

reset.

rollout switch and BVSS requires manual

to flash until b

- Loose bl

- Defective switch or connections.

YES

Do the main burners stay on?

ower motor or capacitor.

estricted vent.

(flame rollout switch open).

-R

- Defective bl

- Inadequate combustion air supply

NO

Repeat call for heat and check flame sensor

- Excessive wind.

- Proper vent sizing.

YES

6.0 microamps.

recheck current. Nominal current is 4.0 to

DC microamps below 0.5?

current during trial for ignition period. Is the

34 IGNITION PROVING FAILURE – If flame

Clean flame sensor with fine steel wool and

NO

xt step.

ollowing items first before

If flame signal is lost during

as valve turned off.

-G

proceeding to the ne

Check the f

come on for the selected blower off-delay.

the blower on-delay period, blower will

#14 occurs.

sequence 3 more times before lockout

period, the control will repeat the ignition

is not sensed during the trial for ignition

YES

YES

Will main burners ignite and stay on?

Is current near typical value?

YES

to furnace sheet metal.

To determine whether the problem is in

- Flame sensor must not be grounded.

- Green/Yellow wire MUST be connected

- Manual shut-off valve.

from the control and initiate the

First remove the R thermostat connection

component test mode to check the igniter.

the system can be operated in the

the gas valve, igniter, or flame sensor

Fixed.

the 15 second warm-up period?

igniter glow orange/white by the end of

component test sequence. Does the

* Blocked vent shutoff switch used in Chimney Adapter Kit

Blower runs for the selected blower off-

check system.

low-heat, high-heat, or cooling cycle to

is interrupted. Run system through a

erased whenever power (115V or 24V)

boards stored status codes can also be

are erased after 72 hours. On RED LED

11 NO PREVIOUS CODE – Stored codes

(115V OR 24V) – Normal operation.

12 BLOWER ON AFTER POWER UP –

period.

W/W1 opens) during the blower on-delay

for heat (R-W/W1 closed) or when (R-

delay, if unit is powered up during a call

occurs if the limit, draft safeguard, flame

13 LIMIT CIRCUIT LOCKOUT – Lockout

Control wi ll

3 minutes.

auto-reset after 3 hours. See code 33.

is open longer than

rollout, or blocked vent switch* (if used)

14 IGNITION LOCKOUT – System failed to

status code 34.

Control will auto-reset after 3 hours. See

ignite gas and prove flame in 4 attempts.

alve.

wired.

ved while gas valve is de-

Check for:

wer and wait 5 minutes to retry.

control.

- Miswire or short to gas valve wire.

- Stuck closed gas valve relay on

Check for:

po

21 GAS HEATING LOCKOUT – Turn off

cleared.

energized. Inducer will run until fault is

Flame is pro

22 ABNORMAL FLAME-PROVING SIGNAL

- Stuck open or leaky gas v

Check for:

23 PRESSURE SWITCH DID NOT OPEN

- Pressure switch stuck closed.

- Obstructed pressure tube.

k for:

(24V) wiring including thermostat

- Short circuit in secondary voltage

OPEN Chec

24 SECONDARY VOLTAGE FUSE IS

to isolate short circuit.

leads. Disconnect thermostat leads

REOPENED - Check for:

RELAY DID NOT CLOSE OR

31 HIGH-HEAT PRESSURE SWITCH OR

ontrol relay may be defective.

- See status code 32.

- Gas valve is mis

-C

A05001

54

Table 18 – Accessory List

DESCRIPTION PAR T NUMBER NOTES

FILCABXX0016 Filter cabinet 16” (406 mm) for 4” (102 mm) wide filter

Media Filter Cabinet

Cartridge Media Filter

EZ Flex Media Filter with End Caps

Replacement EZ Flex Filter Media

External Bottom Return Filter Rack

External Side Return Filter Rack KGAFR0801SRE E x t . S i d e f i l t e r r a c k --- a l l c a s i n g s --- i n c l u d e s f i l t e r

Unframed Filter 3/4--- in. (19 mm)

Flue Extension KGAFE0112UPH (12) vent extension 4” (102 mm) dia. x 3- -- 1/2” (89 mm)

*Twinning Kit KGATW0601HSI Single or two stage PSC equipped units only

Combustible Floor Base KGASB0201ALL Adjustable floor base --- fits all casing sizes

Downflow Vent Guard KGBVG0101DFG Vent flue shield --- downflow venting outside casing

Vent Extension Kit KGAVE0101DNH Downflow, through casing vent extension

Chimney Adapter Kit

N a t u r a l --- t o --- P r o p a n e C o n v e r s i o n K i t KGANP4601ALL Gas conversion natural to propane all

P r o p a n e --- t o --- N a t u r a l C o n v e r s i o n K i t KGAPN3901ALL Gas conversion propane to natural all

Label Kit KGALB0101KIT Downflow orientation label replacement

**ECM Motor Simulator KGASD0301FMS ECM blower and inducer simulator --- variable speed units

**Advanced Product Monitor KGAFP0301APM PC software and hardware for Troubleshooting variable speed units

* Not for ECM or variable --- speed ECM models
** Variable--- speed ECM models only

FILCABXX0020 Filter cabinet 20” (508 mm) for 4” (102 mm) wide filter

FILCABXX0024 Filter cabinet 24” (610 mm) for 4” (102 mm) wide filter

FILXXCAR0016 Filter Cartridge replacements for FILCAB media cabinet

FILXXCAR0020 Filter Cartridge replacements for FILCAB media cabinet

FILXXCAR0024 Filter Cartridge replacements for FILCAB media cabinet

EXPXXUNV0016 16” (406 mm) Replacement Expandable Filter assembly

EXPXXUNV0020 20” (508 mm) Replacement Expandable Filter assembly

EXPXXUNV0024 24” (610 mm) Replacement Expandable Filter assembly

EXPXXFIL0016 16” (406 mm) Replacement filter for EXPUNV assembly

EXPXXFIL0020 20” (508 mm) Replacement filter for EXPUNV assembly

EXPXXFIL0024 24” (610 mm) Replacement filter for EXPUNV assembly

KGAFR0401B14 Bottom return filter rack 14” (356 mm) casing

KGAFR0501B17 Bottom return filter rack 17” (432 mm) casing

KGAFR0601B21 Bottom return filter rack 21” (533 mm) casing

KGAFR0701B24 Bottom return filter rack 24” (610 mm) casing

KGAWF1301UFR† (1) unframed filter 16x25x3/4 (406x635x19 mm)

KGAWF1401UFR (1) unframed filter 20x25x3/4 (508x635x19 mm)

KGAWF1501UFR (1) unframed filter 24x25x3/4 (610x635x19 mm)

KGAWF1306UFR† (6) unframed filter 16x25x3/4 (406x635x19 mm)

KGAWF1406UFR (6) unframed filter 20x25x3/4 (508x635x19 mm)

KGAWF1506UFR (6) unframed filter 24x25x3/4 (610x635x19 mm)

KGACA02014FC Masonry chimney adapter 4” (102 mm)

KGACA02015FC Masonry chimney adapter 5” (127 mm)

312AAV

55

PARTS REPLACEMENT INFORMATION GUIDE

CASING GROUP

Outer door
Blower door
Top filler plate
Bottom filler plate
Bottom enclosure

ELECTRICAL

Control bracket
Junction box
Limit switch(es)
Circuit board
Door switch
Transformer
Wiring harness 115v

312AAV

Wiring harness 24v

BLOWER

GROUP

Blower housing
Blower cutoff
Blower motor
Blower wheel
Capacitor (where used)
Capacitor strap (where used)
Grommet
Power choke (where used)

GROUP

GAS CONTROL

GROUP

Manifold
Burner assembly
Orifice
Flame sensor
Hot surface igniter
Gas valve
Manual reset limit switches
Burner support assembly

HEAT EXCHANGER

GROUP

Heat exchanger cell
Cell panel
Lox NOx baffle (California models only)

INDUCER

GROUP

Housing assembly
Pressure switch
Inducer motor
Inducer wheel
Vent elbow assembly
Draft safeguard switch

TO OBTAIN INFORMATION ON PARTS: Consult your installing dealer or classified section of your local telephone directory under
“Heating Equipment” or “Air Conditioning Contractors and Systems” headings for dealer listing by brand name or contact:

BRYANT HEATING & COOLING SYSTEMS

Consumer Relations Department

P.O. Box 4952

Syracuse, New York 13221--4952

1--800--428--4326

Have available the model number, series number, and serial number located on the unit rating plate to ensure correct replacement part.

Example of Model Number

COOLING

SIZE

(AIRFLOW)

HEATING

SIZE

VARIATION SERIES VARIATION

MODEL

VO LTAG E

IGNITION

TYPE

312A A V 036 110 A E JA

WARNING: Improper installation, adjustment, alteration, service, or maintenance can cause personal injury, property damage, or death.
Consult a qualified installer, service agency, or your local gas supplier for information or assistance. The qualified installer or service agency
must use only factory--authorized replacement parts, kits, or accessories when modifying this product.

EBryant Heating & Cooling Systems 7310 W. Mo rris St. Indianapolis, IN 46231 Printed in U.S.A. Edition Date: 08/10

Manufacturer reserves the right to discontinue, or change at a ny ti me, speci fications or designs without notice and without incurring obl igations.

56

Catalog No. II312A--- 4 5 --- 1 0

Replaces: II312A--- 45---9