Ducane 97G2DF110CV20 Instruction/Installation Manual

INSTALLATION INSTRUCTIONS

Warm Air Gas Furnace

Downow Air Discharge

97G2DFV

This manual must be left with the homeowner for future reference.

This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in manuals, be alert to
the potential for personal injury or death.

Direct Vent & Non-Direct Vent

Table of Contents

Unit Dimensions ........................................................ 2

WARNING

Improper installation, adjustment, alteration, service
or maintenance can cause property damage, personal
injury or loss of life. Installation and service must be
performed by a licensed professional installer (or
equivalent), service agency or the gas supplier.

CAUTION

As with any mechanical equipment, personal injury can
result from contact with sharp sheet metal edges. Be
careful when you handle this equipment.

Parts Arrangement..................................................... 3

Gas Furnace .............................................................. 4

Shipping and Packing List ......................................... 4

Safety Information ..................................................... 4

General ...................................................................... 6

Combustion, Dilution & Ventilation Air ....................... 7

Installation ............................................................... 10

Filters ....................................................................... 12

Duct System ............................................................ 12

Venting Practices ..................................................... 15

Condensate Piping .................................................. 31

Gas Piping ............................................................... 34

Electrical .................................................................. 36

Testing for Proper Venting and Su󰀩cient Combustion

Air for Non-Direct Vent Applications ........................ 44

Unit Start-Up ............................................................ 45

Blower Performance ................................................ 48

Service..................................................................... 50

Planned Service ...................................................... 52

Repair Parts List ...................................................... 52

Manufactured By

Allied Air Enterprises LLC

A Lennox International, Inc. Company

215 Metropolitan Drive

West Columbia, SC 29170

508405-01 Page 1 of 53Issue 2332

*P508405-01*

(P) 508405-01

9/16

(14)

Unit Dimensions

9/16

(14)

Flue Condensate Trap Assembly

Furnished for external
field installation
on either side of unit.
(See installation instructions
for additional
information.)

A

B

AIR

FLOW

9/16

(14)

33

(838)

COMBUSTION

AIR INTAKE

7

(178)

EXHAUST AIR

GAS PIPING INLET

(Either Side)

9-1/8 (232) Right
6-9/16 (167) Left

OUTLET

2-1/16 (52)

1 (25)

Front Panel

2 (51)

Either Side

5

(127)

RETURN AIR

B

OPENING

2-1/4

(57)

9/16

(14)

TOP VIEW

27-3/4

(705)

19-7/16

(494)

ELECTRICAL INLET

(Either Side)

CONDENSATE

TRAP CONNECTION

(Either Side)

6-7/16 (163)

Either Side

9 (229)

Either Side

3/4

(19)

C

Supply

Air

3/4

(19)

19-1/4

(489)

Supply

FRONT VIEW SIDE VIEW

Capacity

070-16 17-1/2 446 16-3/8 416 16 406

090-20
110-20

in. mm in. mm in. mm

21 533 19-7/8 504 19-1/2 495

A B C

Air

3/4

(19)

508405-01Page 2 of 53 Issue 2332

Parts Arrangement

Blower Assembly

Control Box

Access Panel

Combustion Air

Inducer

Gas Valve

Burner Box

Assembly

Figure 1.

508405-01 Page 3 of 53Issue 2332

Gas Furnace

Shipping and Packing List

This Category IV gas furnace is shipped ready for

installation in the downow position.

The furnace is equipped for installation in natural gas
applications. A conversion kit (ordered separately) is
required for use in LP/propane gas applications.

This unit can be installed as either a Direct Vent or a Non­Direct Vent gas central furnace.

NOTE: In Direct Vent installations, combustion air is taken

from outdoors and ue gases are discharged outdoors.

Non-Direct Vent installations, combustion air is taken from

indoors or ventilated attic or crawl space and ue gases
are discharged outdoors. See Figure 2 and Figure 3 for
application involving roof termination.

Package 1 of 1 contains:

1 - Assembled Gas Unit

1 - Bag assembly containing the following:

1 - Snap bushing

1 - Snap Plug

1 - Wire tie

1 - Condensate trap

1 - Condensate trap cap

1 - Condensate trap clamp

1 - 2” diameter debris screen

1 - 3/4” Threaded street elbow

Check equipment for shipping damage. If you nd any

damage, immediately contact the last carrier.

Please refer to specication sheets for available

accessories.

Safety Information

Figure 2.

DANGER

DANGER OF EXPLOSION!

There are circumstances in which odorant used with
LP/propane gas can lose its scent. In case of a leak,

LP/propane gas will settle close to the oor and may be
di󰀩cult to smell. An LP/propane leak detector should be

installed in all LP applications.

Use only the type of gas approved for use with this furnace.
Refer to unit nameplate.

This unit is CSA International certied to ANSI Z21.47 and

CSA 2.3 standards.

Building Codes

In the USA, installation of gas furnaces must conform with
local building codes. In the absence of local codes, units
must be installed according to the current National Fuel

Gas Code (ANSI Z223.1/NFPA 54). The National Fuel Gas

Code is available from the American National Standards
Institute, Inc., 11 West 42nd Street, New York, NY 10036.

In Canada, installation must conform with current National
Standard of Canada CSA-B149 Natural Gas and Propane
Installation Codes, local plumbing or waste water codes
and other applicable local codes.

Figure 3.

In order to ensure proper unit operation in non-direct vent
applications, combustion and ventilation air supply must

508405-01Page 4 of 53 Issue 2332

be provided according to the current National Fuel Gas
Code or CSA-B149 standard.

Locations and Clearances

This furnace is CSA International certied for installation

clearances to combustible material as listed on the unit
nameplate and in the table in Figure 14. Accessibility

and service clearances must take precedence over re

protection clearances.

NOTE: When furnace is installed on a combustible oor,
a downow combustible ooring base must be installed
between the furnace and the oor.

For installation in a residential garage, the furnace must be
installed so that the burner(s) and the ignition source are

located no less than 18 inches (457 mm) above the oor.

The furnace must be located or protected to avoid physical
damage by vehicles. When a furnace is installed in a public
garage, hangar, or other building that has a hazardous
atmosphere, the furnace must be installed according to
recommended good practice requirements and current
National Fuel Gas Code or CSA B149 standards.

NOTE: Furnace must be adjusted to obtain a temperature
rise within the range specied on the unit nameplate.
Failure to do so may cause erratic limit operation and
premature heat exchanger failure.

This gas furnace must be installed so that its electrical
components are protected from water.

Figure 4.

In Canada, all electrical wiring and grounding for the unit
must be installed according to the current regulations of
the Canadian Electrical Code Part I (CSA Standard C22.1)
and/or local codes.

NOTE: This furnace is designed for a minimum continuous
return air temperature of 60°F (16°C) or an intermittent
operation down to 55°F (13°C) dry bulb for cases where a
night setback thermostat is used. Return air temperature
must not exceed 85°F (29°C) dry bulb.

Installed in Combination with a Cooling Coil

When this furnace is used with cooling units (Figure 4),
it shall be installed in parallel with, or on the upstream
side of, cooling units to avoid condensation in the heating

compartment. With a parallel ow arrangement, a damper
(or other means to control the ow of air) must adequately

prevent chilled air from entering the furnace. If the damper
is manually operated, it must be equipped to prevent
operation of either the heating or the cooling unit, unless it
is in the full HEAT or COOL setting.

When installed, this furnace must be electrically grounded
according to local codes. In addition, in the United States,
installation must conform with the current National
Electric Code, ANSI/NFPA No. 70. The National Electric
Code (ANSI/NFPA No. 70) is available from the following
address:

National Fire Protection Association
1 Battery March Park
Quincy, MA 02269

This gas furnace may be installed in alcoves, closets,
attics, basements, garages, and utility rooms.

This furnace design has NOT been CSA certied for

installation in mobile homes, recreational vehicles, or
outdoors.

Never use an open ame to test for gas leaks. Check all

connections using a commercially available soap solution

made specically for leak detection.

Use of Furnace as a Construction Heater

Units may be used for heating of buildings or structures
under construction, if the following conditions are met to
ensure proper operation.

DO NOT USE THE UNIT FOR CONSTRUCTION HEAT
UNLESS ALL OF THE FOLLOWING CRITERIA ARE
MET:

a. Furnace must be in its nal location. The vent system

must be permanently installed per these installation
instructions.

b. Furnace must be installed as a two pipe system

and one hundred percent (100%) outdoor air must
be provided for combustion air requirements during
construction.

508405-01 Page 5 of 53Issue 2332

c. A room thermostat must control the furnace. The use

of xed jumpers that will provide continuous heating is

prohibited.

d. The input rate and temperature rise must be set per

the furnace rating plate.

e. Supply and Return air ducts must be provided and

sealed to the furnace. Return air must be terminated
outside of the space where furnace is installed.

f. Return air temperature range between 60°F (16°C)

and 80°F (27°C) must be maintained.

g. MERV 11 or greater air lters must be installed in

the system and must be regularly inspected and
maintained (e.g., regular static checks and replaced at
end of life) during construction.

h. Blower and vestibule access panels must be in place

on the furnace at all times.

i. The furnace heat exchanger, components, duct

system, and evaporator coils must be thoroughly

cleaned following nal construction clean−up.

j. Air lters must be replaced upon construction

completion.

k. All furnace operating conditions (including ignition,

input rate, temperature rise and venting) must

be veried in accordance with these installation

instructions.

EQUIPMENT MAY EXPERIENCE PREMATURE
COMPONENT FAILURE AS A RESULT OF FAILURE TO
FOLLOW THE ABOVE INSTALLATION INSTRUCTIONS.
FAILURE TO FOLLOW THE ABOVE INSTALLATION
INSTRUCTIONS VOIDS THE MANUFACTURER’S
EQUIPMENT LIMITED WARRANTY. ALLIED AIR
DISCLAIMS ALL LIABILITY IN CONNECTION WITH
INSTALLER’S FAILURE TO FOLLOW THE ABOVE
INSTALLATION INSTRUCTIONS.

NOTWITHSTANDING THE FOREGOING, INSTALLER
IS RESPONSIBLE FOR CONFIRMING THAT THE USE
OF CONSTRUCTION HEAT IS CONSISTENT WITH
THE POLICIES AND CODES OF ALL REGULATING
ENTITIES. ALL SUCH POLICIES AND CODES MUST BE
ADHERED TO.

General

These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.

In addition to the requirements outlined previously, the
following general recommendations must be considered
when installing one of these furnaces:

• Place the furnace as close to the center of the air
distribution system as possible. The furnace should
also be located close to the vent termination point.

• When the furnace is installed in non-direct vent
applications, do not install the furnace where drafts
might blow directly into it. This could cause improper
combustion and unsafe operation.

• When the furnace is installed in a non-direct vent
applications, do not block the furnace combustion air

opening with clothing, boxes, doors, etc. Air is needed

for proper combustion and safe unit operation.

• When the furnace is installed in an attic or other
insulated space, keep insulation away from the
furnace.

• When the furnace is installed in an unconditioned
space, consider provisions required to prevent freezing
of the condensate drain system.

NOTE: The Commonwealth of Massachusetts stipulates
these additional requirements:

• Gas furnaces shall be installed by a licensed plumber

or tter only.

• The gas cock must be “T handle” type.

• When a furnace is installed in an attic, the passageway
to and service area surrounding the equipment shall

be oored.

CAUTION

These units should not be installed in areas normally
subject to freezing temperatures.

508405-01Page 6 of 53 Issue 2332

Combustion, Dilution & Ventilation Air

If this unit is installed as a Non-Direct Vent Furnace, follow
the guidelines in this section.

NOTE: In Non-Direct Vent Installations, combustion air is

taken from indoors and ue gases are discharged outdoors.

the National Fuel Gas Code (ANSI-Z223.1/NFPA 54). This
reprinted material is not the complete and o󰀩cial position

of ANSI on the referenced subject, which is represented
only by the standard in its entirely.

In Canada, refer to the CSA B149 Installation codes.

CAUTION

WARNING

Insu󰀩cient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rusting
and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result

in safety and performance related problems. Avoid

exposure to the following substances in the combustion

air supply:

• Permanent wave solutions

• Chlorinated waxes and cleaners

• Chlorine base swimming pool chemicals

• Water softening chemicals

• De-icing salts or chemicals

• Carbon tetrachloride

• Halogen type refrigerants

• Cleaning solvents (such as perchloroethylene)

• Printing inks, paint removers, varnishes, etc.

• Hydrochloric acid

• Cements and glues

• Antistatic fabric softeners for clothes dryers

• Masonry acid washing materials

In the past, there was no problem in bringing in su󰀩cient
outdoor air for combustion. Inltration provided all the air

that was needed. In today’s homes, tight construction
practices make it necessary to bring in air from outside

for combustion. Take into account that exhaust fans,
appliance vents, chimneys, and replaces force additional

air that could be used for combustion out of the house.
Unless outside air is brought into the house for combustion,
negative pressure (outside pressure is greater than inside
pressure) will build to the point that a down draft can
occur in the furnace vent pipe or chimney. As a result,
combustion gases enter the living space creating a
potentially dangerous situation.

In the absence of local codes concerning air for combustion
and ventilation, use the guidelines and procedures in this

section to install these furnaces to ensure e󰀩cient and safe

operation. You must consider combustion air needs and

requirements for exhaust vents and gas piping. A portion

of this information has been reprinted with permission from

Do not install the furnace in a corrosive or contaminated
atmosphere. Meet all combustion and ventilation air
requirements, as well as all local codes.

All gas-red appliances require air for the combustion
process. If su󰀩cient combustion air is not available,
the furnace or other appliance will operate ine󰀩ciently

and unsafely. Enough air must be provided to meet the
needs of all fuel-burning appliances and appliances such

as exhaust fans which force air out of the house. When
replaces, exhaust fans, or clothes dryers are used at the

same time as the furnace, much more air is required to
ensure proper combustion and to prevent a down draft.

Insu󰀩cient air causes incomplete combustion which can
result in carbon monoxide.

In addition to providing combustion air, fresh outdoor air
dilutes contaminants in the indoor air. These contaminants
may include bleaches, adhesives, detergents, solvents
and other contaminants which can corrode furnace
components.

The requirements for providing air for combustion and
ventilation depend largely on whether the furnace is

installed in an unconned or a conned space.

Unconned Space

An unconned space is an area such as a basement

or large equipment room with a volume greater than 50
cubic feet (1.42 m³) per 1,000 Btu (.29 kW) per hour of
the combined input rating of all appliances installed in that
space. This space also includes adjacent rooms which are
not separated by a door. Though an area may appear to

be unconned, it might be necessary to bring in outdoor air

for combustion if the structure does not provide enough air

by inltration. If the furnace is located in a building of tight

construction with weather stripping and caulking around
the windows and doors, follow the procedures in the “Air
from Outside” section.

Conned Space

A conned space is an area with a volume less than 50

cubic feet (1.42 m³) per 1,000 Btu (.29 kW) per hour of
the combined input rating of all appliances installed in that

space. This denition includes furnace closets or small

equipment rooms.

When the furnace is installed so that supply ducts carry
air circulated by the furnace to areas outside the space

508405-01 Page 7 of 53Issue 2332

containing the furnace, the return air must be handled by
ducts which are sealed to the furnace casing and which
terminate outside the space containing the furnace. This
is especially important when the furnace is mounted on

a platform in a conned space such as a closet or small

equipment room. Even a small leak around the base of the
unit at the platform or at the return air duct connection can
cause a potentially dangerous negative pressure condition.
Air for combustion and ventilation can be brought into the

conned space either from inside the building or from

outside.

Air from Inside

If the conned space that houses the furnace adjoins a
space categorized as unconned, air can be brought in

by providing two permanent openings between the two
spaces. Each opening must have a minimum free area of 1
square inch (645 mm²) per 1,000 Btu (.29 kW) per hour of

total input rating of all gas-red equipment in the conned

space. Each opening must be at least 100 square inches
(64516 mm²). One opening shall be within 12 inches (305
mm) of the top of the enclosure and one opening within 12
inches (305 mm) of the bottom. See Figure 5.

It is also permissible to bring air for combustion from a
ventilated attic (Figure 9) or ventilated crawl space (Figure

10).

Figure 6. Equipment in Conned Space - All Air from

Outside

(Inlet Air from Crawl Space and Outlet Air to

Ventilated Attic)

Figure 5. Equipment in Conned Space - All Air from

Inside

Air from Outside

If air from outside is brought in for combustion and

ventilation, the conned space shall be provided with two

permanent openings. One opening shall be within 12” (305
mm) of the top of the enclosure and one within 12” (305 mm)
of the bottom. These openings must communicate directly
or by ducts with the outdoors or spaces (crawl or attic) that
freely communicate with the outdoors or indirectly through
vertical ducts. Each opening shall have a minimum free
area of 1 square inch per 4,000 Btu (645 mm² per .59 kW)
per hour of the total input rating of all equipment in the
enclosure (see Figure 6 and Figure 7).

When communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of 1
square inch (645 mm²) per 2,000 Btu (.56 kW) per hour of
the total input rating of all equipment in the enclosure. See
Figure 8.

When ducts are used, they shall be of the same cross­sectional area as the free area of the openings to which
they connect. The minimum dimension of rectangular
air ducts shall be no less than 3 inches (75 mm). In

calculating free area, the blocking e󰀨ect of louvers, grilles,

or screens must be considered. If the design and free area
of protective covering is not known for calculating the size
opening required, it may be assumed that wood louvers
will have 20 to 25 percent free area and metal louvers and
grilles will have 60 to 75 percent free area. Louvers and

grilles must be xed in the open position or interlocked

with the equipment so that they are opened automatically
during equipment operation.

508405-01Page 8 of 53 Issue 2332

Figure 7. Equipment in Conned Space - All Air from

Outside

(All Air Through Ventilated Attic)

Ventilation Louvers

Roof Terminated

Exhaust Pipe

*Intake Debris

Screen

(Provided)

Furnace

Inlet Air
(Minimum 12 in.
(305mm) above

Attic Floor)

* See Maximum Vent Lengths table

NOTE-The inlet and outlet air openings shall each have a
free area of at least one square inch per 4,000 Btu (645mm2
per 1.17kW) per hour of the total input rating of all equipment
in the enclosure.

Figure 9. Equipment in Conned Space

(Inlet Air from Ventilated Attic and Outlet Air to

Outside)

Roof Terminated

Exhaust Pipe

Figure 8. Equipment in Conned Space - All Air from

Outside

WARNING

If this unit is being installed in an application with
combustion air coming in from a space serviced by an

exhaust fan, power exhaust fan, or other device which

may create a negative pressure in the space, take care
when sizing the inlet air opening. The inlet air opening

must be sized to accommodate the maximum volume
of exhaust air as well as the maximum volume of

combustion air required for all gas appliances serviced
by this space.

Inlet Air

Minimum

Ventilation

Louvers

(Crawl Space)

Coupling or
3 in. to 2 in.

Transition

(Field Provided)

Furnace

12 in. (305mm)

above Crawl
Space Floor

*Intake Debris Screen Provided

* See Maximum Vent Lengths table

NOTE-The inlet and outlet air openings shall each have a
free area of at least one square inch per 4,000 Btu (645mm
per 1.17kW) per hour of the total input rating of all equipment
in the enclosure.

2

Figure 10. Equipment in Conned Space

(Inlet Air from Ventilated Crawl Space and Outlet Air

to Outside)

508405-01 Page 9 of 53Issue 2332

Installation

Setting Equipment

WARNING

Do not install the furnace on its front, back or in the
horizontal position. See Figure 13. Do no connect the
return air ducts to the back of the furnace. Doing so

will adversely a󰀨ect the operation of the safety control

devices, which could result in personal injury or death.

Select a location that allows for the required clearances
that are listed on the unit nameplate. Also consider gas
supply connections, electrical supply, vent connection,
condensate trap and drain connections, and installation
and service clearances [24 inches (610 mm) at unit front].
The unit must be level from side to side. Tilt the unit slightly

(maximum 1/2 in. from level) from back to front to aid in the
draining of the heat exchanger. See Figure 12.

Shipping Bolt Removal

NOTE: Units with a 1/2 hp blower motors are equipped

with three exible legs and one rigid leg. The rigid leg
is equipped with a shipping bolt and a at white plastic
washer (rather than the rubber mounting grommet used
with a exible mounting leg). See Figure 11. The bolt and
washer must be removed before the furnace is placed into
operation. After the bolt and washer have been removed,
the rigid leg will not touch the blower housing.

Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or
alcove installations are shown in Figure 14.

Units with 1/2 HP Blower Motor

Figure 12. Setting Equipment

Figure 13.

WARNING

Improper installation of the furnace can result in

personal injury or death. Combustion and ue products

must never be allowed to enter the return air system or
air in the living space. Use sheet metal screws and joint
tape to seal return air system to furnace.

In platform installations with furnace return, the furnace
should be sealed airtight to the return air plenum. A door
must never be used as a portion of the return air duct
system. The base must provide a stable support and an
airtight seal to the furnace. Allow absolutely no sagging,
cracks, gaps, etc.

For no reason should return and supply air duct systems
ever be connected to or from other heating devices

such as a replace or stove, etc. Fire, explosion, carbon
monoxide poisoning, personal injury and/or property

damage could result.

Figure 11.

WARNING

Blower access panel must be securely in place when
blower and burners are operating. Gas fumes, which

could contain carbon monoxide, can be drawn into

living space resulting in personal injury or death.

The unit may be installed three ways in downow
applications: on non-combustible ooring, on combustible
ooring using an additive base, or on a reverse-ow
cooling coil cabinet. Do not drag the unit across the oor
in the downow position. Floor and furnace ange damage

will result.

Refer to Figure 14 for clearances in downow applications.

508405-01Page 10 of 53 Issue 2332

Top 0

* Front 0

Back 0

Sides 0†

Vent 0

Floor NC‡

* Front clearance in alcove installation must be 24 in. (610
mm). Maintain a minimum of 24 in. (610 mm) for front service
access.

† Allow proper clearances to accommodate condensate trap.

‡ The furnace may be installed on a combustible wood oor if

an optional additive base is installed between the furnace and

the combustible oor.

Figure 14. Downow Application Installation

Clearances

Installation on Non-Combustible Flooring

1. Cut oor opening keeping in mind clearances listed
on unit rating plate. Also keep in mind gas supply

connections, electrical supply, ue and air intake
connections and su󰀩cient installation and servicing
clearances. See Table 1 for correct oor opening size.

2. Flange warm air plenum and lower the plenum into the
opening.

3. Set the unit over the plenum and seal the plenum to
the unit.

4. Ensure that the seal is adequate.

Figure 15.

Installation on Combustible Flooring

1. When unit is installed on a combustible oor, a
downow combustible ooring base must be installed
between the furnace and the oor. The base must be

ordered separately. See Table 2 for opening size to

cut in oor.

CAUTION

The furnace and combustible ooring base shall not be

installed directly on carpeting, tile, or other combustible

material other than wood ooring.

Cabinet

Width

B cabinet
(17.5”)

C cabinet
(21”)

Catalog
Number

11M60

11M61 22-3/4 578

Table 2. Combustible Flooring Base Opening Size

Front to Rear Side to Side

in. mm in. mm

18-3/4 476

22 559

Cabinet Width

B cabinet (17.5”)

C cabinet (21”) 20-1/8 511

NOTE: Floor opening dimensions listed are 1/4 in. (6 mm)
larger than the unit opening. See dimension drawing on Page

2.

Front to Rear Side to Side

in. mm in. mm

16-5/8 422

19-3/4 502

Table 1. Non-Combustible Floor Opening Size

508405-01 Page 11 of 53Issue 2332

Figure 16.

2. After opening is cut, set the combustible ooring base
into opening.

3. Check berglass strips on the combustible ooring
base to make sure they are properly glued and
positioned.

4. Lower supply air plenum into the combustible ooring

base until plenum anges seal against berglass

strips.

NOTE: Be careful not to damage berglass strips.
Check for a tight seal.

5. Set the furnace over the plenum.

6. Ensure that the seal between the furnace and plenum
is adequate.

Installation on Cooling Coil Cabinet

NOTE: Downow combustible ooring kit is not used.

1. Refer to reverse-ow coil installation instructions for
correctly sized opening in oor and installation of

cabinet.

2. When cooling cabinet is in place, set and secure the
furnace according to the instructions that are provided
with the cooling coil. Secure the furnace to the cabinet.

3. Seal the cabinet and check for air leaks.

Figure 18.

Figure 19.

Filters

Figure 17.

Return Air Opening - Downow Units

Return air may be brought in only through the top opening of

a furnace installed in the downow position. The following

steps should be taken when installing plenum:

1. Bottom edge of plenum should be anged with a
hemmed edge (see Figure 18 or Figure 19).

2. Sealing strips should be used to ensure an airtight
seal between the cabinet and the plenum.

3. In all cases, plenum should be secured to top of
furnace using sheet metal screws.

4. Make certain that an adequate seal is made.

This unit is not equipped with a lter or rack. A eld provided
lter is required for the unit to operate properly. Table 3 lists
recommended lter sizes.

A lter must be in place whenever the unit is operating.

Furnace Cabinet Width Filter Size

17-1/2”

21”

Table 3.

16 x 25 x 1 (1)

Duct System

Use industry-approved standards to size and install the
supply and return air duct system. This will result in a quiet
and low-static system that has uniform air distribution.

NOTE: This furnace is not certied for operation in heating
mode (indoor blower operating at selected heating speed)
with an external static pressure which exceeds 0.8 inches
w.c. Operation at these conditions may result in improper
limit operation.

Supply Air Plenum

If the furnace is installed without a cooling coil, a removable
access panel should be installed in the supply air duct. The
access panel should be large enough to permit inspection

(by reected light) of the heat exchanger for leaks after the

508405-01Page 12 of 53 Issue 2332

furnace is installed. The furnace access panel must always
be in place when the furnace is operating and it must not
allow leaks into the supply air duct system.

Return Air Plenum

NOTE: Return air must not be drawn from a room where

this furnace, or any other gas-fueled appliance (i.e., water
heater), or carbon monoxide-producing device (i.e., wood
replace) is installed.

When return air is drawn from a room, a negative pressure
is created in the room. If a gas appliance is operating in

a room with negative pressure, the ue products can be

pulled back down the vent pipe and into the room. This

reverse ow of the ue gas may result in incomplete
combustion and the formation of carbon monoxide gas.
This toxic gas might then be distributed throughout the

house by the furnace duct system.

Use berglass sealing strips, caulking, or equivalent

sealing method between the plenum and the furnace

cabinet to ensure a tight seal. If a lter is installed, size the
return air duct to t the lter frame.

Pipe & Fittings Specications

All pipe, ttings, primer and solvent cement must conform

with American National Standard Institute and the American
Society for Testing and Materials (ANSI/ASTM) standards.

The solvent shall be free owing and contain no lumps,

undissolved particles or any foreign matter that adversely

a󰀨ects the joint strength or chemical resistance of the
cement. The cement shall show no gelation, stratication,

or separation that cannot be removed by stirring. Refer to

Table 4 below for approved piping and tting materials.

Piping and Fittings Specications

Schedule 40 PVC (Pipe) D1785

Schedule 40 PVC (Fittings) D2466

Schedule 40 CPVC (Pipe) F441

Schedule 40 CPVC (Fittings) F438

SDR-21 PVC or SDR-26 PVC (Pipe) D2241

SDR-21 CPVC or SDR-26 CPVC (Pipe) F442

Schedule 40 ABS (Pipe) D1527

Schedule 40 ABS (Fittings) D2468
ABS-DWV (Drain Waste & Vent)

(Pipe & Fittings)
PVC-DWV (Drain Waste & Vent)

Pipe & Fittings)

PRIMER & SOLVENT CEMENT

PVC & CPVC Primer F656

PVC Solvent Cement D2564

CPVC Solvent Cement F493

ABS Solvent Cement D2235
PVC/CPVC/ABS All Purpose Cement For

Fittings & Pipe of the same material
ABS to PVC or CPVC Transition Solvent

Cement

CANADA PIPE & FITTING & SOLVENT

CEMENT

PVC & CPVC Pipe and Fittings

ABS to PVC or CPVC Transition Cement

POLYPROPYLENE VENTING SYSTEM

PolyPro® by Duravent

InnoFlue® by Centrotherm ULC-S636

ECCO Polypropylene Vent

TM

D2661

D2665

ASTM

SPECIFICATION

D2564, D2235,

F493

D3138

MARKING

ULCS636PVC & CPVC Solvent Cement

ULC-S636

ULC-S636

CAUTION

Solvent cements for plastic pipe are ammable liquids

and should be kept away from all sources of ignition.

Do not use excessive amounts of solvent cement when

making joints. Good ventilation should be maintained to

reduce re hazard and to minimize breathing of solvent

vapors. Avoid contact of cement with skin and eyes.

IMPORTANT

The exhaust and intake connections are made of PVC.

Use PVC primer and solvent cement when using PVC
vent pipe. When using ABS vent pipe, use transitional

solvent cement to make connections to the PVC tting

in the unit.

508405-01 Page 13 of 53Issue 2332

Table 4.

Use PVC primer and solvent cement or ABS solvent

cement meeting ASTM specications, refer to Table 4.

As an alternate, use all purpose cement, to bond ABS,

PVC, or CPVC pipe when using ttings and pipe made of

the same materials. Use transition solvent cement when
bonding ABS to either PVC or CPVC.

Low temperature solvent cement is recommended during
cooler weather. Metal or plastic strapping may be used as
vent pipe hangers. Uniformly apply a liberal coat of PVC
primer for PVC or use a clean dry cloth for ABS to clean

inside socket surface of tting and male end of pipe to
depth of tting socket.

Canadian Applications Only

Pipe, ttings, primer and solvent cement used to vent
(exhaust) this appliance must be certied to ULC S636 and

supplied by a single manufacturer as part of an approved

vent (exhaust) system. When bonding the vent system to

the furnace, use ULC S636 approved One-Step Transition

Cement to bond the pipe to the ue collar. In addition, the

rst three feet of vent pipe from the furnace ue collar must

be accessible for inspection.

Table 5 lists the available exhaust termination kits. All vent

terminations are PVC.

Joint Cementing Procedure

All cementing of joints should be done according to the

specications outlined in ASTM D 2855.

NOTE: A sheet metal screw may be used to secure the
intake pipe to the connector, if desired. Use a drill or self
tapping screw to make a pilot hole.

DANGER

DANGER OF EXPLOSION!

Fumes from PVC glue may ignite during system check.
Allow fumes to dissipate for at least 5 minutes before
placing unit into operation.

1. Measure and cut vent pipe to desired length.

2. Debur and chamfer end of pipe, removing any ridges
or rough edges. If end is not chamfered, edge of pipe

may remove cement from tting socket and result in a

leaking joint.

3. Clean and dry surfaces to be joined.

4. Test t joint and mark depth of tting on outside of pipe.

5. Uniformly apply a liberal coat of PVC primer for PVC
or use a clean dry cloth for ABS to clean inside socket

surface of tting and male end of pipe to depth of tting

socket.

6. Promptly apply solvent cement to end of pipe and

inside socket surface of tting. Cement should be

applied lightly but uniformly to inside of socket. Take

care to keep excess cement out of socket. Apply

second coat to end of pipe.

NOTE: Time is critical at this stage. Do Not allow
primer to dry before applying cement.

STANDARD CONCENTRIC

Outdoor

VENT

Capacity

070

090

110

1

2 inch to 1-1/2 inch reducer required, must be eld provided.

* Requires eld-provided and installed 1-1/2” exhaust accelerator.

** Kit 51W11 is provided with a 1-1/2” accelerator, which must be used for all 70,000 furnace installations. When using 1-/2 in. piping,

the pipe must be transitioned to 2 in. pipe when used with the Flush Mount Kit.

† Termination kits 44W92, 44W93, 30G28 and 81J20 approved for use in Canadian installations to meet CSAB149.

†† The 44W92 concentric kit is provided with a 1-1/2” accelerator, which must be installed on the exhaust outlet when this kit is used

with the 70,000 furnaces. When using 1-1/2 in. piping, the pipe must be transitioned to 2 in. pipe when used with the Concentric
Kit.

PIPE DIA.

(in.)

1

1-1/2 YES YES

2 YES YES YES

2-1/2" YES YES YES

3 YES YES YES

2 YES YES YES YES

2-1/2" YES YES YES YES

3 YES YES YES YES

2 YES YES YES YES

2-1/2" YES YES YES YES

3 YES YES YES YES

Exhaust

Accelerator

(Dia. X Length)

1-1/2" x 12" 2" x 12" 51W11**

Outdoor
Exhaust

Accelerator

(Dia. X Length)

Flush Mount

Kit

1-1/2"

Concentric Kit

71M80

OR

+44W92++

2" Concentric

Kit

69M29

OR

+44W92++

3" Concentric

Kit

60L46

OR

44W93+

Table 5. Outdoor Termination Kits Usage

508405-01Page 14 of 53 Issue 2332

7. Immediately after applying last coat of cement to pipe,
and while both inside socket surface and end of pipe
are wet with cement, forcefully insert end of pipe into
socket until it bottoms out. Turn PVC pipe 1/4 turn
during assembly (but not after pipe is fully inserted) to
distribute cement evenly. Do not turn ABS or cellular
core pipe.

NOTE: Assembly should be completed within 20
seconds after last application of cement. Hammer
blows should not be used when inserting pipe.

8. After assembly, wipe excess cement from pipe at end
of tting socket. A properly made joint will show a bead

around its entire perimeter. Any gaps may indicate

an improper defective assembly due to insu󰀩cient

solvent.

9. Handle joints carefully until completely set.

Venting Practices

Figure 20. Piping Suspension Guidelines

Removal of the Furnace from Common Vent

In the event that an existing furnace is removed from

a venting system commonly run with separate gas
appliances, the venting system is likely to be too large to
properly vent the remaining attached appliances.

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 the common venting
system.

2. Inspect the venting system for proper size and
horizontal pitch. Determine that there is no blockage,

restriction, leakage, corrosion, or other deciencies

which could cause an unsafe condition.

3. Close all building doors and windows and all doors
between the space in which the appliances remaining
connected to the common venting system are located
and other spaces of the building. Turn ON clothes
dryers and any appliances not connected to the

common venting system. Turn ON any exhaust fans,
such as range hoods and bathroom exhausts, so they
will operate at maximum speed. Do not operate a
summer exhaust fan. Close replace dampers.

4. Follow the lighting instructions. Turn ON the appliance
that is being inspected. Adjust the thermostat so that
the appliance operates continuously.

5. After the main burner has operated for 5 minutes, test

for leaks of ue gases at the draft hood relief opening.
Use the ame of a match or candle.

6. After determining that each appliance connected to
the common venting system is venting properly, (step

3) return all doors, windows, exhaust fans, replace

dampers, and any other gas burning appliances to
their previous mode of operation.

7. If a venting problem is found during any of the
preceding tests, the common venting system must be

modied to correct the problems.

Resize the common venting system to the minimum vent
pipe size determined by using the appropriate tables in

Appendix G. These are in the current standards of the
National Fuel Gas Code ANSI Z223.1.

Conduct the following test while each appliance is operating
and the other appliances (which are not operating) remain
connected to the common venting system. If the venting
system has been installed improperly, you must correct the
system as indicated in the general venting requirements
section.

508405-01 Page 15 of 53Issue 2332

Figure 21.

Vent Piping Guidelines

This gas furnace can be installed as either a Non-Direct
Vent or a Direct Vent gas central furnace.

NOTE: In non-Direct Vent installations, combustion air is

taken from indoors and ue gases are discharged outdoors.

In Direct Vent installations, combustion air is taken from

outdoors and ue gases are discharged outdoors.

Intake and exhaust pipe sizing - Size pipe according to

Table 6 and Table 7A through Table 7C. Table 6 lists the
minimum vent pipe lengths permitted. Table 7A through

Table 7C lists the maximum pipe lengths permitted.

Regardless of the diameter of pipe used, the standard roof

and wall terminations described in section Exhaust Piping
Terminations should be used. Exhaust vent termination
pipe is sized to optimize the velocity of the exhaust gas as
it exits the termination.

Capacity Min. Vent Length*

15 ft. or

070, 090, 110

* Any approved termination may be added to the minimum
length listed.

5 ft. plus 2 elbows or

10 ft. plus 1 elbow

1. In areas where piping penetrates joist or interior walls,
hole must be large enough to allow clearance on all
sides of pipe through center of hole using a hanger.

2. When furnace is installed in a residence where unit

is shut down for an extended period of time, such

as a vacation home, make provisions for draining
condensate collection trap and lines.

Exhaust Piping

Route piping to outside of structure. Continue with
installation following instructions given in piping termination
section.

CAUTION

Do not discharge exhaust into an existing stack or

stack that also serves another gas appliance. If vertical

discharge through an existing unused stack is required,

insert PVC pipe inside the stack until the end is even
with the top or outlet end of the metal stack.

Table 6. Minimum Vent Pipe Lengths

In some applications which permit the use of several

di󰀨erent sizes of vent pipe, a combination vent pipe may

be used. Contact Allied Air Technical Service for assistance
in sizing vent pipe in these applications.

IMPORTANT

Do not use screens or perforated metal in exhaust or

intake terminations. Doing so will cause freeze-ups and
may block the terminations.

CAUTION

The exhaust vent pipe operates under positive pressure

and must be completely sealed to prevent leakage of
combustion products into the living space.

508405-01Page 16 of 53 Issue 2332

Use the following steps to correctly size vent pipe diameter.

070, 090,

110

Standard or
Concentric?
See Table 5

Intake or

Exhaust?

1-1/2”, 2”,

2-1/2”

or 3”

Furnace capacity?

1

Which termination?

2

Which needs most
elbows?

3

How many?

4

Desired pipe size?

5

What is the altitude?

6

Use Table 7 to find
max pipe length.

7

Figure 22.

508405-01 Page 17 of 53Issue 2332

Maximum Allowable Intake or Exhaust Vent Length in Feet

Standard Termination at Elevation 0 - 4,500 ft

Number of

90° Elbows

Used

1 15

2 10 46 24

3

4 36 14 85 63 28 107 88 88

5 31 9 80 58 23 102 83 83

6 26

7 21 70 48 13 92 73 73

8 16 65 43 8 87 68 68

9 11 60 38

10 6 55 33 77 58 58

Number of

90° Elbows

Used

1 15

2 10 46 24 95 73 38 11 7 98 98

3

4 36 14 85 63 28 107 88 88

5 31 9 80 58 23 102 83 83

6 26

7 21 70 48 13 92 73 73

8 16 65 43 8 87 68 68

9 11 60 38

10 n/a 55 33 77 58 58

*Size intake and exhaust pipe length separately. Values in table are for intake OR Exhaust, not combined total. Both Intake and
Exhaust must be same pipe size.

1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3" Pipe

Capacity Capacity Capacity Capacity

070 090 110 070 090 11 0 070 090 110 070 090 11 0

51 29 9 100 78 43 122 103 103

95 73 38 117 98 98

41 19 90 68 33 112 93 93

n/a n/a

n/a

n/a

Standard Termination at Elevation 4,501 - 10,000 ft

1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3" Pipe

Capacity Capacity Capacity Capacity

070 090 110 070 090 11 0 070 090 110 070 090 11 0

51 29

41 19 90 68 33 112 93 93

n/a n/a

n/a

n/a

n/a

n/a

75 53 18 97 78 78

n/a

100 78 43 122 103 103

75 53 18 97 78 78

n/a

82 63 63

82 63 63

Table 7A.

508405-01Page 18 of 53 Issue 2332

Maximum Allowable Intake or Exhaust Vent Length in Feet

Concentric Termination at Elevation 0 - 4,500 ft

Number of

90° Elbows

Used

1

2 38 22

3 33 17 80 64 29 96 89 89

4 28 12 75 59 24 91 84 84

5 23 7 70 54 19 86 79 79

6 18

7 13 60 44 9 76 69 69

8

9 50 34 66 59 59

10 45 29 61 54 54

Number of

90° Elbows

Used

1

2 38 22 85 69 34 101 94 94

3 33 17 80 64 29 96 89 89

4 28 12 75 59 24 91 84 84

5 23 7 70 54 19 86 79 79

6 18

7 13 60 44 9 76 69 69

8 8 55 39

9

10 45 29 61 54 54

*Size intake and exhaust pipe length separately. Values in table are for intake OR Exhaust, not combined total. Both Intake and
Exhaust must be same pipe size.

1-1/2” Pipe 2” Pipe 2-1/2" Pipe 3" Pipe

Capacity Capacity Capacity Capacity

070 090 110 070 090 11 0 070 090 110 070 090 11 0

43 27 7 90 74 39 106 99 99

85 69 34 101 94 94

n/a n/a n/a

n/a

n/a

Concentric Termination at Elevation 4,501 - 10,000 ft

1-1/2” Pipe 2” Pipe 2-1/2" Pipe 3" Pipe

Capacity Capacity Capacity Capacity

070 090 110 070 090 11 0 070 090 110 070 090 11 0

43 27

n/a n/a n/a

n/a

n/a

n/a

n/a

65 49 14 81 74 74

55 39

n/a

90 74 39 106 99 99

65 49 14 81 74 74

50 34 66 59 59

n/a

71 64 64

71 64 64

Table 7B.

508405-01 Page 19 of 53Issue 2332

Maximum Allowable Exhaust Vent Length Using Ventilated Attic or Crawl Space for Intake Air in Feet

Standard Termination at Elevation 0 - 10,000 ft

Number of

90° Elbows

Used

1

1-1/2” Pipe 2” Pipe 2-1/2" Pipe 3" Pipe

Capacity Capacity Capacity Capacity

070 090 110 070 090 11 0 070 090 110 070 090 11 0

41 24

85 63 28 102 83 83

2 36 19 80 58 23 97 78 78

3 31 14 75 53 18 92 73 73

4 26 9 70 48 13 87 68 68

5 21 4 65 43 8 82 63 63

6 16

7 11 55 33

8 6 50 28 67 48 48

9 1 45 23 62 43 43

n/a n/a n/a

n/a

n/a

60 38 3 77 58 58

72 53 53

n/a

10 n/a 40 18 57 38 38

NOTE: Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length
calculation.

Table 7C.

Pipe size determined in table 7.

2”

2”

* When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible.
NOTE: Exhaust pipe and intake pipe must be the same diameter.

2”

2”

or

DO NOT transition

from smaller to larger

pipe in horizontal runs

of exhaust pipe.

2”

3”

TRANSITION

*2”

DO NOT transition

from larger to smaller

pipe in horizontal runs

of exhaust pipe.

or

NOTE: 1-1/2” Vent Pipe
Diameter Allowed Only
on 045/070 Units

1-1/2”

TRANSITION

*2”

Figure 23. Typical Exhaust Pipe Connections

INTAKE

EXHAUST

TOP VIEW

508405-01Page 20 of 53 Issue 2332

Pipe size determined in table 7.

2”

2”

3”

TRANSITION

*2”

* When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible.
NOTE: Exhaust pipe and intake pipe must be the same diameter.

2”

or

or

Figure 24. Typical Intake Pipe Connections (Direct Vent Applications)

Intake Piping

This furnace may be installed in either direct vent or non­direct vent applications. In non-direct vent applications,
when intake air will be drawn into the furnace from
the surrounding space, the indoor air quality must be
considered. Guidelines listed in Combustion, Dilution and
Ventilation Air section must be followed.

2”

NOTE: 1-1/2” Vent Pipe
Diameter Allowed Only
on 045/070 Units

1-1/2”

TRANSITION

*2”

2”

INTAKE

EXHAUST

*2”

TOP VIEW

TRANSITION

*2”

3”

2. If intake air is drawn from a ventilated crawl space

(Figure 26) or ventilated attic (Figure 25) the exhaust
vent length must not exceed those listed in Table 7C.

If 3” diameter pipe is used, reduce to 2” diameter pipe
to accommodate the debris screen.

3. Use a sheet metal screw to secure the intake pipe to
the connector, if desired.

Use the following steps when installing the unit in Direct
Vent applications, where combustion air is taken from

outdoors and ue gases are discharged outdoors. The

provided air intake screen must not be used in direct vent
applications (outdoors).

1. Use cement or a sheet metal screw to secure the
intake pipe to the inlet air connector.

2. Route piping to outside of structure. Continue with
installation following instructions given in general
guide lines for piping terminations and intake and

exhaust piping terminations for direct vent sections.

Refer to Table 7A through Table 7C for pipe sizes.

Use the following steps when installing the unit in Non­Direct Vent applications where combustion air is taken

from indoors and ue gases are discharged outdoors.

1. Use eld-provided materials and the factory-provided
air intake screen to route the intake piping. Maintain
a minimum clearance of 3” (76 mm) around the air
intake opening. The air intake opening (with the
protective screen) should always be directed forward,
or sideways.

Roof Terminated

Exhaust Pipe

Ventilation Louvers

*Intake Debris

Screen

(Provided)

Furnace

Inlet Air
(Minimum 12 in.
(305mm) above

Attic Floor)

* See Maximum Vent Lengths table

NOTE-The inlet and outlet air openings shall each have a
free area of at least one square inch per 4,000 Btu (645mm2
per 1.17kW) per hour of the total input rating of all equipment
in the enclosure.

Figure 25. Equipment in Conned Space

(Inlet Air from Ventilated Attic and Outlet Air to

Outside)

508405-01 Page 21 of 53Issue 2332

Roof Terminated

Exhaust Pipe

Inlet Air

Minimum

Ventilation

Louvers

(Crawl Space)

Coupling or
3 in. to 2 in.

Transition

(Field Provided)

Furnace

12 in. (305mm)

above Crawl
Space Floor

*Intake Debris Screen Provided

* See Maximum Vent Lengths table

NOTE-The inlet and outlet air openings shall each have a
free area of at least one square inch per 4,000 Btu (645mm
per 1.17kW) per hour of the total input rating of all equipment
in the enclosure.

2

Figure 26. Equipment in Conned Space

(Inlet Air from Ventilated Crawl Space and Outlet Air

to Outside)

WARNING

If this unit is being installed in an application with
combustion air coming in from a space serviced by an

exhaust fan, power exhaust fan, or other device which

may create a negative pressure in the space, take care
when sizing the inlet air opening. The inlet air opening

must be sized to accommodate the maximum volume
of exhaust air as well as the maximum volume of

combustion air required for all gas appliances serviced
by this space.

General Guidelines for Vent Terminations

In Non-Direct Vent applications, combustion air is taken

from indoors and the ue gases are discharged to the
outdoors. This unit is then classied as a non-direct vent,

Category IV gas furnace.

In Direct Vent applications, combustion air is taken from

outdoors and the ue gases are discharged to the outdoors.
This unit is then classied as a direct vent, Category IV gas

furnace.

In both Non-Direct Vent and Direct Vent applications, the
vent termination is limited by local building codes. In the
absence of local codes, refer to the current National Fuel

Gas Code ANSI Z223-1/NFPA 54 in U.S.A., and current

CSA-B149 Natural Gas and Propane Installation Codes in
Canada for details.

Position termination according to location given in Figure
28 or Figure 29. In addition, position termination so it is
free from any obstructions and 12” above the average
snow accumulation.

At vent termination, care must be taken to maintain
protective coatings over building materials (prolonged

exposure to exhaust condensate can destroy protective
coatings). It is recommended that the exhaust outlet not be

located within 6 feet (1.8 m) of a condensing unit because
the condensate can damage the painted coating.

NOTE: See Table 8 for maximum allowed exhaust pipe
length without insulation in unconditioned space during
winter design temperatures below 32° F (0° C). If required,
exhaust pipe should be insulated with 1/2” (13 mm),
Armaex or equivalent when run through an unconditioned
area. In extremely cold climate areas with temperature
below 20° F (6.7° C) it is recommended that 3/4” (19 mm)
Armaex or equivalent be used. Insulation on outside
runs of exhaust pipe should be painted or wrapped to
protect insulation from deterioration in accordance with
the insulation manufacturers recommendation. Exhaust
pipe insulation may not be necessary in some specic
applications.

NOTE: During extremely cold temperatures, below
approximately 20° F (6° C), units with long runs of vent
pipe through unconditioned space, even when insulated,
may form ice in the exhaust termination that prevents the
unit from operating properly. Longer run times of at least 5
minutes will alleviate most icing problems. Also, a heating
cable may be installed on exhaust piping and termination
to prevent freeze-ups. Heating cable installation kits are
available, see unit specication sheets for part numbers.

IMPORTANT

Do not use screens or perforated metal in exhaust

terminations. Doing so will cause freeze-ups and may
block the terminations.

IMPORTANT

For Canadian Installations Only:

In accordance to CSA International B149 installation
codes, the minimum allowed distance between the

combustion air intake inlet and the exhaust outlet of

other appliances shall not be less than 12 inches (305
mm).

508405-01Page 22 of 53 Issue 2332

Maximum Allowable Exhaust Vent Pipe Length3 (in ft.) without Insulation in Unconditioned Space for Winter Design

Temperatures

Winter Design Temperatures

(ºC)

1

ºF

Vent Pipe

Diameter

070 090 110

PVC

2

PP PVC

Unit Input Size

2

PP PVC

2

PP

1-1/2 in. 20 N/A N/A N/A N/A N/A

32 to 21

(0 to -6)

2 in. 33 30 46 42 30 30

2-1/2 in. 26 N/A 37 N/A 36 N/A

3 in. 21 21 30 30 29 29

1-1/2 in. 20 N/A N/A N/A N/A N/A

20 to 1

(-7 to -17)

2 in. 19 17 28 25 27 24

2-1/2 in. 14 N/A 21 N/A 20 N/A

3 in. 9 9 16 16 14 14

1-1/2 in. 13 N/A N/A N/A N/A N/A

0 to -20

(-18 to -29)

2 in. 12 10 19 16 18 15

2-1/2 in. 7 N/A 13 N/A 12 N/A

3 in. N/A N/A 8 8 7 7

1

Refer to 99% Minimum Design Temperature table provided in the current edition of the ASHRAE Fundamentals Handbook.

2

Poly-Propylene vent pipe (PP) by Duravent and Centrotherm

3

Vent length in table is equivalent length. Each elbow is equivalent to 5ft of straight pipe and should be included when measuring

total length.

NOTE - Concentric terminations are the equivalent of 5’ and should be considered when measuring pipe length.

NOTE- Maximum uninsulated vent lengths listed may include the termination (vent pipe exterior to the structure ) and cannot exceed

5 linear feet or the maximum allowable intake or exhaust vent length listed in Table 6 or Table 7A through Table 7C.

NOTE - If insulation is required an unconditioned space, it must be located on the pipe closed to the furnace.

Conditioned

Space

Table 8.

Conditioned

Space

Pipe Insulation

Unconditioned

Space

Exhaust

Pipe

Intake

Pipe

Figure 27. Insulating Exhaust Pipe in an Unconditioned Space

508405-01 Page 23 of 53Issue 2332

VENT TERMINATION CLEARANCES

FOR NON-DIRECT VENT INSTALLATIONS IN THE US AND CANADA

INSIDE CORNER

DETAIL

G

D

A

E

B

L

C

Fixed

F

Closed

Operable

B

B

B

VENT TERMINAL

AIR SUPPLY INLET

US Installations

A =

B =

C =

Clearance above grade, veranda,

porch, deck or balcony

Clearance to window or

door that may be opened

Clearance to permanently

12 inches (305mm) or 12 inches (305mm)

above average snow accumulation.

4 feet (1.2 m) below or to side of opening;

1 foot (30cm) above opening

closed window

Vertical clearance to ventilated soffit

D =

located above the terminal within a

* Equal to or greater than soffit depth.

horizontal distance of 2 feet (610 mm)

from the center line of the terminal

E =

F =

G =

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

H =

tended above meter / regulator assembly

I =

Clearance to service regulator

vent outlet

J =

Clearance to non-mechanical air

* Equal to or greater than soffit depth.

* No minimum to outside corner * No minimum to outside corner

3 feet (.9m) within a height 15 feet (4.5m)

*

above the meter / regulator assembly

* 3 feet (.9m)

4 feet (1.2 m) below or to side of opening;

1 foot (30 cm) above opening

pliance

K =

ply inlet

L =

Clearance above paved sidewalk or

paved driveway located on public property

M =

Clearance under veranda, porch, deck or balcony

1

In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code

In accordance with the current CSA B149.1, Natural Gas and Propane Installation

2

Code

†

A vent shall not terminate directly above a sidewalk or paved driveway that is
located between two single family dwellings and serves both dwellings.

‡

Permitted only if veranda, porch, deck or balcony is fully open on a minimum of
two sides beneath the floor. Avoiding this location is recommended if possible.

3 feet (.9m) above if within 10 feet

(3m) horizontally

7 feet (2.1m)†

*12 inches (305mm)‡

Operable

A

* 12”

H

Fixed

Closed

J

B

I

M

K

AREA WHERE TERMINAL
IS NOT PERMITTED

1

Canadian Installations

2

12 inches (305mm) or 12 inches (305mm)

above average snow accumulation.

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

* 12”

* Equal to or greater than soffit depth.

* Equal to or greater than soffit depth.

**

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

3 feet (.9m)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

6 feet (1.8m)

7 feet (2.1m)†

12 inches (305mm)‡

*For clearances not specified in ANSI Z223.1/NFPA 54 or CSA
B149.1, clearance will be in accordance with local installation
codes and the requirements of the gas supplier and these
installation instructions.”

NOTE - This figure is intended to illustrate clearance
requirements and does not serve as a substitute for locally
adopted installation codes.

Figure 28. Vent Termination Clearances

For Non-Direct Vent Installations in the USA and Canada

508405-01Page 24 of 53 Issue 2332

VENT TERMINATION CLEARANCES

FOR DIRECT VENT INSTALLATIONS IN THE USA AND CANADA

INSIDE CORNER

DETAIL

G

D

A

E

B

L

C

Fixed

F

Closed

Operable

B

B

B

VENT TERMINAL

AIR SUPPLY INLET

US Installations

A =

B =

Clearance above grade, veranda,

porch, deck or balcony

Clearance to window or

door that may be opened

12 inches (305mm) or 12 inches (305mm)

above average snow accumulation.

6 inches (152mm) for appliances <10,000

Btuh (3kw), 9 inches (228mm) for ap-

pliances > 10,000 Btuh (3kw) and <50,000

Btuh (15kw), 12 inches (305mm) for ap-

pliances > 50,000 Btuh (15kw)

C =

Clearance to permanently

closed window

Vertical clearance to ventilated soffit

D =

located above the terminal within a

horizontal distance of 2 feet (610mm)

* Equal to or greater than soffit depth* Equal to or greater than soffit depth

from the center line of the terminal

E =

F =

G =

H =

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line ex-

tended above meter / regulator assembly

I =

Clearance to service regulator

vent outlet

J =

Clearance to non-mechanical air
supply inlet to building or the com-

bustion air inlet to any other ap-

pliance

* Equal to or greater than soffit depth * Equal to or greater than soffit depth

* No minimum to outside corner

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

*

3 feet (.9m)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 9 inches (228mm) for ap-

pliances > 10,000 Btuh (3kw) and <50,000

Btuh (15kw), 12 inches (305mm) for ap-

pliances > 50,000 Btuh (15kw)

K =

Clearance to mechanical air sup-

ply inlet

Clearance above paved sidewalk or

L =

paved driveway located on public property

Clearance under veranda, porch, deck or balcony

M =

In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code

1

In accordance with the current CSA B149.1, Natural Gas and Propane Installation

2

Code

†

A vent shall not terminate directly above a sidewalk or paved driveway that is
located between two single family dwellings and serves both dwellings.

‡

Permitted only if veranda, porch, deck or balcony is fully open on a minimum of
two sides beneath the floor. Avoiding this location is recommended if possible.

3 feet (.9m) above if within 10 feet

(3m) horizontally

* 7 feet (2.1m)

*12 inches (305mm)‡

Operable

A

* 12”

*

H

Fixed

Closed

J

B

I

M

K

AREA WHERE TERMINAL
IS NOT PERMITTED

1

Canadian Installations

2

12 inches (305mm) or 12 inches (305mm)

above average snow accumulation.

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

* 12”

* No minimum to outside corner

*

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

3 feet (.9m)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

6 feet (1.8m)

7 feet (2.1m)†

12 inches (305mm)‡

*For clearances not specified in ANSI Z223.1/NFPA 54 or CSA
B149.1, clearance will be in accordance with local installation
codes and the requirements of the gas supplier and these
installation instructions.”

NOTE - This figure is intended to illustrate clearance
requirements and does not serve as a substitute for locally
adopted installation codes.

Figure 29. Vent Termination Clearances

For Direct Vent installations in the USA and Canada

508405-01 Page 25 of 53Issue 2332

Details of Intake and Exhaust Piping
Terminations for Direct Vent Installations

NOTE: In Direct Vent installations, combustion air is taken

from outdoors and ue gases are discharged to outdoors.

NOTE: Flue gas may be slightly acidic and may adversely
aect some building materials. If any vent termination
is used and the ue gases may impinge on the building
material, a corrosion-resistant shield (minimum 24 inches
square) must be used to protect the wall surface. If the
optional tee is used, the protective shield is required.
The shield should be constructed using wood, plastic,
sheet metal or other suitable material. All seams, joints,
cracks, etc. in the aected area should be sealed using an
appropriate sealant. See Figure 38.

Intake and exhaust pipes may be routed either horizontally

through an outside wall or vertically through the roof. In
attic or closet installations, vertical termination through the
roof is preferred. Figure 30 through Figure 37 show typical
terminations.

1. Vent terminations are not required to be in the same

pressure zone. You may exit the intake on one side of
the structure and the exhaust on another side (Figure

31). You may exit the exhaust out the roof and the

intake out the side of the structure (Figure 32).

2. Intake and exhaust pipes should be placed as close
together as possible at termination end (refer to
illustrations). Minimum separation is 3” (76 mm)
on roof terminations and 6” (152 mm) on side wall
terminations.

3. On roof terminations, the intake piping should terminate
straight down using two 90° elbows (see Figure 30).

4. Exhaust piping must terminate straight out or up as

shown. A reducer may be required on the exhaust
piping at the point where it exits the structure to
improve the velocity of exhaust away from the intake

piping. See Table 9.

Capacity Exhaust Pipe Size

*070

*090

110 3” (76 mm)

*070 and 090 units with the ush-mount termination must use

the 1-1/2” accelerator supplied with the kit.

2” (51 mm),

2-1/2” (64 mm),

3” (76 mm)

Table 9. Exhaust Pipe Termination Size Reduction

5. On eld supplied terminations for side wall exit,
exhaust piping may extend a maximum of 12 inches

(305 mm) for 2” PVC and 20 inches (508 mm) for 3”
(76 mm) PVC beyond the outside wall. Intake piping
should be as short as possible. See Figure 38.

Termination

Pipe Size

1-1/2” (38 mm)

2” (51 mm)

NOTE: Care must be taken to avoid recirculation of
exhaust back into intake pipe.

6. On eld supplied terminations, a minimum distance
between the end of the exhaust pipe and the end of

the intake pipe without a termination elbow is 8” and a
minimum distance of 6” with a termination elbow. See
Figure 38.

Inches (MM)

8” (203MM) MIN

12” (305MM) ABOVE

AVERAGE SNOW

ACCUMULATION

3” (76MM) OR

2” (51MM) PVC

PROVIDE SUPPORT

FOR INTAKE AND

EXHAUST LINES

3” (76MM) MIN.

SIZE PER EXHAUST PIPE

TERMINATION SIZE
REDUCTION TABLE

UNCONDITIONED

ATTIC SPACE

1/2” (13MM) FOAM

INSULATION IN

UNCONDITIONED

SPACE

Figure 30. Direct Vent Roof Termination Kit

Inlet Air

Exhaust

Pipe

Furnace

Minimum 12 in.

(305MM) above

grade or snow

accumulation

Figure 31. Exiting Exhaust and Intake Vent

(no common pressure zone)

Roof T

erminated

Exhaust Pipe

Inlet Air

Furnace

Minimum 12 in.

(305MM) above

grade or snow

accumulation

Figure 32. Exiting Exhaust and Intake Vent

(no common pressure zone)

508405-01Page 26 of 53 Issue 2332

2” EXTENSION FOR 2” PVC
PIPE1” EXTENSION FOR 3”
PVC PIPE

FURNACE
EXHAUST

PIPE

GLUE EXHAUST

END FLUSH INTO

TERMINATION

1-1/2” ACCELERATOR

FURNACE

INTAKE

PIPE

4''

FLAT
SIDE

(all -45, -070 and -090 units)

Figure 33. Flush-Mount Side Wall Termination 51W11

7. If intake and exhaust piping must be run up a side
wall to position above snow accumulation or other
obstructions, piping must be supported every 24” (610
mm) as shown in Figure 38.

When exhaust and intake piping must be run up an
outside wall, the exhaust piping must be terminated

with pipe sized per Table 9. The intake piping may be
equipped with a 90° elbow turndown. Using turndown
will add 5 feet (1.5 m) to the equivalent length of the
pipe.

8. Based on the recommendation of the manufacturer, a
multiple furnace installation may use a group of up to
four terminations assembled together horizontally, as
shown in Figure 36.

1 1/2” (38mm) accelerator

EXHAUST

12” (305mm)

Minimum

Above Average

Snow

Accumulation

VENT

provided on 71M80 & 44W92

kits for -045 and -070 models

INTAKE

AIR

FLASHING

(Not Furnished)

SHEET METAL STRAP

(Clamp and sheet metal strap
must be field installed to support
the weight of the termination kit.)

CLAMP

FIELD-PROVIDED

REDUCER MAY BE REQUIRED

TO ADAPT DIFFERENT VENT

PIPE SIZE TO TERMINATION

Figure 34. Direct Vent Concentric Rooftop

Termination

71M80, 69M29 or 60L46 (US)

41W92 or 41W93 (Canada)

FIELD-PROVIDED

REDUCER MAY BE REQUIRED

TO ADAPT DIFFERENT VENT

PIPE SIZE TO TERMINATION

OUTSIDE

WALL

EXHAUST

VENT

1-1/2” (38mm) accelerator

provided on 71M80 & 44W92

kits for -045 and -070 models

INTAKE

AIR

EXHAUST

VENT

EXHAUST

VENT

5”

(127mm)

5-1/2”

(140mm)

12”

(305mm)

INTAKE

AIR

18” MAX.
(457mm)

Front View

EXHAUST VENT

12” (305mm) Min.

above grade or

Inches (mm)

INTAKE

cumulation.

AIR

optional intake elbow

Side View

Figure 36. Optional Vent Termination for Multiple Unit

Installation of Direct Vent Wall Termination Kit

STRAIGHT-CUT OR

ANGLE-CUT IN DIRECTION

OF ROOF SLOPE *

(203mm - 305mm)

Minimum 12” (305mm)

above chimney top

plate or average snow

accumulation

* SIZE TERMINATION
PIPE PER EXHAUST
PIPE TERMINATION
SIZE REDUCTION
TABLE

8” - 12”

INTAKE PIPE

INSULATION (optional)

SHEET

METAL TOP

PLATE

INSULATE

TO FORM

SEAL

3” - 8”
(76mm ­203mm)

EXHAUST VENT

1/2” (13mm)

WEATHERPROOF

INSULATION

SHOULDER OF FITTINGS

PROVIDE SUPPORT

OF PIPE ON TOP PLATE

ALTERNATE

INTAKE PIPE

3” - 8”
(76mm ­203mm)

EXTERIOR

PORTION OF

CHIMNEY

INTAKE

AIR

CLAMP

(Not Furnished)

INTAKE

AIR

12” (305mm) Min.

above grade or

average snow
accumulation.

GRADE

Figure 35. Direct Vent Concentric Wall Termination

71M80, 69M29 or 60L46 (US)

41W92 or 41W93 (Canada)

508405-01 Page 27 of 53Issue 2332

NOTE: Do not discharge exhaust gases directly into any chimney
or vent stack. If vertical discharge through an existing unused
chimney or stack is required, insert piping inside chimney until
the pipe open end is above top of chimney and terminates as
illustrated. In any exterior portion of chimney, the exhaust vent
must be insulated.

Figure 37. Direct Vent Application Using Existing

Chimney

NOTE − FIELD−PROVIDED

REQUIRED TO ADAPT

LARGER VENT PIPE SIZE

* WALL

SUPPORT

C1

REDUCER MAY BE

TO TERMINATION

C1

A

E

D

B

Intake
Elbow

STRAIGHT

APPPLICATION

D

B

A

EXTENDED

APPLICATION

FIELD FABRICATED WALL TERMINATION

A− Minimum clearance

above grade or average

snow accumulation

B− Maximum horizontal

separation between

intake and exhaust

C1 -Minimum from end of

exhaust to inlet of intake

C2 -Minimum from end of

exhaust to inlet of intake

D− Maximum exhaust

pipe length

E− Maximum wall support

distance from top of each

pipe (intake/exhaust)

D

B

* Use wall support every 24” (610 mm). Use two
wall supports if extension is greater than
24” (610 mm) but less than 48” (1219 mm).
NOTE − One wall support must be within 6” (152 mm)
from top of each pipe (intake and exhaust) to prevent
movement in any direction.

C2

D

B

C2

A

E

A

2” (51mm)

Vent Pipe

12” (305 mm)

12” (305 mm)

3” (76mm)

Vent Pipe

12” (305 mm)

6” (152 mm)6” (152 mm)

8” (203 mm)8” (203 mm)

6” (152 mm)6” (152 mm)

20” (508 mm)

6” (152 mm)6” (152 mm)

ALTERNATE TERMINATIONS (TEE & FORTY−FIVE DEGREE ELBOWS ONLY)

2” (51MM)

Vent Pipe

12” (305 mm) Min. 12” (305 mm) Min.

6” (152 mm) Min.
24” (610 mm) Max.

9” (227 mm) Min.

12” (305 mm) Min.
16” (405 mm) Max.

6” (152 mm) Max.

Front View of

Intake and Exhaust

Intake

Exhaust

Intake
Elbow

B

C

Exhaust

D

3

A

D

E

B

C

1

12”

A− Clearance above

grade or average snow

accumulation

B− Horizontal

separation between

intake and exhaust

C− Minimum from

end of exhaust to

inlet of intake

D− Exhaust pipe length

E− Wall support distance

from top of each pipe

(intake/exhaust)

2

A

D

B

1

C

2

A

D

E

B

C

1

12”

2

A

1

The exhaust termination tee should be connected to the 2” or 3” PVC flue pipe as shown in the illustration.

Do not use an accelerator in applications that include an exhaust termination tee.
The accelerator is not required.

2

As required. Flue gas may be acidic and may adversely affect some building materials. If a side wall vent

termination is used and flue gases will impinge on the building materials, a corrosion-resistant shield
(24 inches square) should be used to protect the wall surface. If optional tee is used, the protective shield
is recommended. The shield should be constructed using wood, sheet metal or other suitable material.
All seams, joints, cracks, etc. in affected area, should be sealed using an appropriate sealant.

3

Exhaust pipe 45° elbow can be rotated to the side away from the combustion air inlet to direct exhaust
away from adjacent property. The exhaust must never be directed toward the combustion air inlet.

3” (76MM)

Vent Pipe

6” (152 mm) Min.
24” (610 mm) Max.

9” (227 mm) Min.

12” (305 mm) Min.
20” (508 mm) Max.

6” (152 mm) Max.

Figure 38. Field Supplied Wall Termination

508405-01Page 28 of 53 Issue 2332

Details of Exhaust Piping Terminations for Non-

Direct Vent Applications

Exhaust pipe may be routed either horizontally through

an outside wall or vertically through the roof. In attic or
closet installations, vertical termination through the roof
is preferred. Figure 39 through Figure 42 show typical
terminations.

1. Exhaust piping must terminate straight out or up as
shown. The termination pipe must be sized as listed

in Table 9. The specied pipe size ensures proper
velocity required to move the exhaust gases away

from the building.

2. On eld supplied terminations for side wall exit,

exhaust piping may extend a maximum of 12 inches

(305 mm) for 2” PVC and 20” (508 mm) for 3” (76 mm)
PVC beyond the outside wall. See Figure 40.

3. If exhaust piping must be run up a sidewall to position
above snow accumulation or other obstructions, piping
must be supported every 24” (610 mm) as shown in

Figure 41. When exhaust piping must be run up an
outside wall, any reduction in exhaust pipe size must
be done after the nal elbow.

SIZE TERMINATION
PER EXHAUST PIPE
TERMINATION SIZE
REDUCTION TABLE

FIELD-PROVIDED

REDUCER MAY BE

REQUIRED TO

ADAPT DIFFERENT

VENT PIPE SIZE TO

TERMINATION

* Use wall support every 24” (610 mm). Use two supports of extension is greater than 24”

(610 mm) but less than 48” (1219 mm).

Figure 41. Non-Direct Vent Field Supplied Wall

Termination - Extended

* SIZE TERMINATION PIPE PER EXHAUST
PIPE TERMINATION SIZE REDUCTION TABLE

STRAIGHT-CUT OR

ANGLE-CUT IN DIRECTION

OF ROOF SLOPE *

SIZE PER EXHAUST PIPE

12” (305MM)

ABOVE AVE.

SNOW

ACCUMULATION

3” (76MM) OR

2” (51MM) PVC

PROVIDE SUPPORT

FOR EXHAUST LINES

TERMINATION SIZE
REDUCTION TABLE

UNCONDITIONED

ATTIC SPACE

Figure 39. Non-Direct Vent Roof Termination Kit

FIELD-PROVIDED

REDUCER MAY BE

REQUIRED TO

ADAPT DIFFERENT

VENT PIPE SIZE TO

TERMINATION

SIZE TERMINATION
PER EXHAUST PIPE
TERMINATION SIZE
REDUCTION TABLE

Minimum 12” (305mm)

above chimney top

plate or average snow

accumulation

INTAKE PIPE

INSULATION (optional)

METAL TOP

INSULATE

TO FORM

SEAL

SHEET

PLATE

EXHAUST VENT

1/2” (13mm)

WEATHERPROOF

INSULATION

SHOULDER OF FITTINGS

PROVIDE SUPPORT

OF PIPE ON TOP PLATE

EXTERIOR

PORTION OF

CHIMNEY

NOTE: Do not discharge exhaust gases directly into any
chimney or vent stack. If vertical discharge through an existing

unused chimney or stack is required, insert piping inside
chimney until the pipe open end is above top of chimney and

terminate as illustrated. In any exterior portion of chimney, the
exhaust vent must be insulated.

Figure 42. Non-Direct Vent Application Using Existing

Chimney

Figure 40. Non-Direct Vent Field Supplied Wall

Termination

508405-01 Page 29 of 53Issue 2332

Exhaust through Crawl Space Vent Option

All 33” condensing gas furnaces (92%+) are now approved
to be vented down through a crawl space. Ensure a vent

pipe drain kit, 51W18 (USA) or 15Z70 (Canada), is used as
directed through the oor joists and into the crawl space.
See the following gures.

Consult the vent tables for vent lengths and approved
materials.

From

Furnace

2” or 3”

Sanitary Tee

1/2” PVC

Drain Stub

Drain Trap

Assembly

Rubber Boot (51W18)
Drain Plug (15Z70)

Clamp

(51W18 Only)

To Vent

Termination

Drain Trap

(assembled)

Exhaust from

Furnace

To Termination

Exhaust from

Furnace

To Termination

* Kit 51W18 is shown.

Figure 44. Crawl Space Vent Pipe Drain Trap

Assembled Incorrectly

Figure 43. Kit 51W18 (USA) / 15Z70 (Canada) Parts

Identication and Assembly

Downflow Furnace

Exhaust

KIT 51W18 (USA)
KIT 15Z70 (Canada)

24” max.

* Kit 51W18 is shown.

Basement Floor

To Termination

1/2” PVC to

Code-Approved

Drain

NOTE: Upow furnaces exhaust from the left side. All dimensions shown are typical for upow or downow furnaces.
NOTE: All horizontal runs of exhaust pipe must slope back toward the kit a minimum of 1/4” (6mm) for each 12” (305mm) to ensure drainage.

Figure 45. Upow or Downow Furnace with Exhaust through Crawl Space

508405-01Page 30 of 53 Issue 2332

Condensate Piping

This unit is designed for either right or left side exit of
condensate piping in downow applications. Refer to

Figure 46 for condensate trap locations.

NOTE: If necessary the condensate trap may be installed
up to 5 feet away using PVC pipe from the furnace. Piping
from furnace must slope down a minimum of 1/4” per ft.
toward trap.

1. Determine which side condensate piping will exit the

unit, location of trap, eld-provided ttings and length

of PVC pipe required to reach available drain.

2. Use a large at head screw driver or a 1/2” drive

socket extension and remove plug (Figure 46) from
the cold end header box at the appropriate location

on the side of the unit. Install provided 3/4 NPT street

elbow tting into cold end header box. Use Teon tape

or appropriate pipe dope.

3. Install the cap over the clean out opening at the base

of the trap. Secure with clamp. See Figure 51.

4. Install drain trap using appropriate PVC ttings, glue

all joints. Glue the provided drain trap as shown in
Figure 51. Route the condensate line to an open drain.
Condensate line must maintain a 1/4” downward slope
from the furnace to the drain.

NOTE: Vinyl tubing may be used for condensate drain.
Tubing must be 1-1/4” OD x 1” ID and should be attached
to the drain on the trap using a hose clamp.

5. Figure 48 shows the furnace and evaporator coil
using a separate drain. If necessary, the condensate
line from the furnace and evaporator coil can drain

together. See Figure 49. The eld provided vent must
be a minimum 1” to a maximum 2” length above the

condensate drain outlet connection.

CAUTION

Do Not use copper tubing or existing copper condensate

lines for drain line.

Trap

(same on

right side)

1-1/2 in.

Plug
(same on
left side)

Figure 47. Condensate Trap Location

(shown with right side exit of condensation)

6. If unit will be started immediately upon completion of
installation, prime trap per procedure outlined in Unit
Start-Up section.

Condensate line must slope downward away from the
trap to drain. If drain level is above condensate trap,
condensate pump must be used. Condensate drain line
should be routed within the conditioned space to avoid
freezing of condensate and blockage of drain line. If
this is not possible, a heat cable kit may be used on the
condensate trap and line. Heating cable kit is available in
various lengths; 6 ft. (1.8 m) - kit no. 26K68; 24 ft. (7.3 m) ­kit no. 26K69; and 50 ft. (15.2 m) - kit no. 26K70.

Figure 46. Condensate Trap and Plug Locations

508405-01 Page 31 of 53Issue 2332

Field Provided Vent

1” min. 2” max. above

condensate drain.

Condensate

Drain Connection

Evaporator Drain Line

(vent required)

Drain

From Evaporator Coil

Optional

Overflow Switch

Field-Provided Vent

(Upflow Furnace 1” Min. to 2” Max.

Horizontal Furnace 4” Min. to 5” Max.

above condensate drain connection)

Furnace Condensate

Drain Connection

Figure 48. Evaporator Coil Using a Separate Drain

CAUTION

When combining the furnace and evaporator coil
drains together, the A/C condensate drain outlet must
be vented to relieve pressure in order for the furnace
pressure switch to operate properly.

Field Provided Vent

1” min. 2” max. above

condensate drain.

Condensate

Drain Connection

Evaporator Drain Line

(vent required)

Figure 50. Condensate Trap with Optional Overow

Switch

Figure 49. Evaporator Coil Using a Common Drain

508405-01Page 32 of 53 Issue 2332

Optional Condensate Drain Connection

Adapter 3/4 inch slip X

3/4 inch mpt (not furnished)

90° Street Elbow
3/4 inch PVC
(not furnished)

Condensate Drain

Connection In Unit

90° Street Elbow
3/4 inch PVC
( furnished)

To

Trap

Optional Drain Piping From Tr ap

Drain Assembly for 1/2 inch Drain Pipe

1/2 inch PVC Pipe

(Not Furnished)

90° Elbow

1/2 inch PVC

(Not Furnished)

To

Drain

Drain Assembly for 3/4 inch Drain Pipe

1(25 mm) Min.
2 (50 mm) Max.
AboveTop Of
Condensate Drain
Connection In Unit

Elbow 3/4 inch PVC

90°

(Not Furnished)

1/2 inch PVC Pipe

(Not Furnished)

Adapter 3/4 inch slip X

3/4 inch mpt (not furnished)

V

ent

5 Feet

Maximum

3/4 inch PVC Pipe

(Not Furnished)

Coupling 3/4 inch slip X slip

(Not Furnished)

Drain Trap

Assembly

(Furnished)

Condensate Drain

Connection In Unit

90° Elbow

3/4 inch PVC

(Not Furnished)

To

Drain

DrainTr ap Assembly

(Furnished)

7

(178)

Drain Trap
Clean Out

90° Elbow

3/4 inch PVC

(Not Furnished)

o

T

Coupling 3/4 inch slip X slip

Drain

DrainTr ap Assembly with 1/2 inch Piping

1 (25 mm) Min. 2 (50 mm) Max. AboveTop
Of Condensate Drain Connection In Unit

(Not Furnished)

Vent

1/2 inch

Condensate Drain

Connection In Unit

To

Drain

DrainTr ap Assembly with 3/4 inch Piping

1 (25 mm) Min. 2 (50 mm) Max. AboveTop
Of Condensate Drain Connection In Unit

Vent

3/4 inch

Condensate Drain

Connection In Unit

To

Drain

Figure 51. Trap Drain Assembly Using 1/2” PVC or 3/4” PVC

508405-01 Page 33 of 53Issue 2332

Gas Piping

CAUTION

If a exible gas connector is required or allowed by

the authority that has jurisdiction, black iron pipe shall

be installed at the gas valve and extend outside the
furnace cabinet. The exible connector can then be

added between the black iron pipe and the gas supply
line.

WARNING

Do Not exceed 600 in. lbs. (50 ft. lbs.) torque when

attaching the gas piping to the gas valve.

1. Gas piping may be routed into the unit through either
the left or right hand side. Supply piping enters into
the gas valve from the side of the valve as shown in
Figure 53.

IMPORTANT

Compounds used on threaded joints of gas piping must

be resistant to the actions of liquied petroleum gases.

Leak Check

After gas piping is completed, carefully check all eld-

installed piping connections for gas leaks. Use a

commercially available leak detecting solution specically
manufactured for leak detection. Never use an open ame

to test for gas leaks.

The furnace must be isolated from the gas supply

system by closing the individual manual shut-o󰀨 valve

during any gas supply system at pressures greater than
or equal to 1/2 psig (3.48 kPa, 14 inches w.c.). This
furnace and its components are designed, manufactured

and independently certied to comply with all applicable

ANSI/CSA standards. A leak check of the furnace and its
components is not required.

IMPORTANT

A low inlet pressure switch in LP/propane applications
is recommended.

2. When connecting gas supply, factors such as length

of run, number of ttings and furnace rating must be
considered to avoid excessive pressure drop. Table 10

lists recommended pipe sizes for typical applications.

NOTE: Use two wrenches when connecting gas piping
to avoid transferring torque to the manifold.

3. Gas piping must not run in or through air ducts,
clothes chutes, chimneys or gas vents, dumb waiters
or elevator shafts. Center gas line through piping hole.
Gas line should not touch side of unit. See Figure 53.

4. Piping should be sloped 1/4 inch per 15 feet (6 mm per

5.6 m) upward toward the gas meter from the furnace.
The piping must be supported at proper intervals,
every 8 to 10 feet (2.44 to 3.05 m), using suitable
hangers or straps. Install a drip leg in vertical pipe runs
to serve as a trap for sediment or condensate.

5. A 1/8” N.P.T. plugged tap or pressure post is located
on the gas valve to facilitate test gauge connection.

6. In some localities, codes may require installation of a

manual main shut o󰀨 valve and union (furnished by
installer) external to the unit. Union must be of the

ground joint type.

Figure 52.

IMPORTANT

When testing pressure of gas lines, gas valve must
be disconnected and isolated. Gas Valves can be
damaged if subjected to pressures greater than 1/2 psig
(3.48 kPa).

WARNING

FIRE OR EXPLOSION HAZARD

Failure to follow the safety warnings exactly could

result in serious injury, death, or property damage.

Never use an open ame to test for gas leaks. Check

all connections using a commercially available soap

solution made specically for leak detection. Some

soaps used for leak detection are corrosive to certain
metals. Carefully rinse piping thoroughly after leak test
has been completed.

508405-01Page 34 of 53 Issue 2332

MANUAL

MAIN SHUT-OFF

VALV E

(With 1/8 in. NPT

Plugged Tap Shown)

GROUND

JOINT

UNION

Left Side Piping

(Standard)

AUTOMATIC

GAS VALV E

(with manual

shut-off valve)

AUTOMATIC

GAS VALV E

(with manual

shut-off valve)

MANUAL

MAIN SHUT-OFF

VALV E

(With 1/8 in. NPT

Plugged Ta p

Shown)

GROUND

JOINT

UNION

DRIP LEG

Right Side Piping

DRIP LEG

FIELD

PROVIDED

AND INSTALLED

NOTE - BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET

Figure 53.

Gas Pipe Capacity - FT³/HR (kL/HR)

Nominal

Iron Pipe

Size -

inches

(mm)

1/2

(12.7)

3/4

(19.05)

1

(25.4)

1-1/4

(31.75)

1-1/2

(38.1)

2

(50.8)

2-1/2

(63.5)

3

(76.2)

4

(101.6)

Internal

Diameter

- inches

(mm)

.622

(17.799)

.824

(20.930)

1.049

(26.645)

1.380

(35.052)

1.610

(40.894)

2.067

(52.502)

2.469

(67.713)

3.068

(77.927)

4.026

(102.260)

10

(3.048)20(6.096)30(9.144)40(12.192)50(15.240)60(18.288)70(21.336)80(24.384)90(27.432)

175

(4.96)

360

(10.19)

680

(19.25)

1400

(39.64)

2100

(59.46)

3950

(111.85)

6300

(178.39)

11000

(311.48)

23000

(651.27)

120

(3.40)97(2.75)82(2.32)73(2.07)66(1.87)61(1.73)57(1.61)53(1.50)50(1.42)

250

(7.08)

465

(13.17)

950

(26.90)

460

(41.34)

2750

(77.87)

4350

(123.17)

7700

(218.03)

15800

(447.39)

200

(5.66)

375

(10.62)

770

(21.80)

1180

(33.41)

2200

(62.30)

3520

(99.67)

6250

(176.98)

12800

(362.44)

NOTE: Capacity given in cubic feet of gas per hour (kilo liters of gas per hour) and based on 0.60 specic gravity gas.

Length of Pipe - feet (m)

170

(4.81)

320

(9.06)

660

(18.69)

990

(28.03)

1900

(53.80)

3000

(84.95)

5300

(150.07)

10900

(308.64)

151

(4.28)

285

(8.07)

580

(16.42)

900

(25.48)

1680

(47.57)

2650

(75.04)

4750

(134.50)

9700

(274.67)

138

(3.91)

260

(7.36)

530

(15.01)

810

(22.94)

1520

(43.04)

2400

(67.96)

4300

(121.76)

9700

(274.67)

125

(3.54)

240

(6.80)

490

(13.87)

750

(21.24)

1400

(39.64)

2250

(63.71)

3900

(110.43)

8100

(229.36)

118

(3.34)

220

(6.23)

460

(13.03)

690

(19.54)

1300

(36.81)

2050

(58.05)

3700

(104.77)

7500

(212.37)

(12.18)

(18.41)

(34.55)

(55.22)

(97.69)

(203.88)

(Alternate)

110

(3.11)

205

(5.80)

430

650

1220

1950

3450

7200

100

(30.480)

103

(2.92)

195

(5.52)

400

(11.33)

620

(17.56)

1150

(32.56)

1850

(52.38)

3250

(92.03)

6700

(189.72)

Table 10.

508405-01 Page 35 of 53Issue 2332

Electrical

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

Electrostatic discharge can a󰀨ect electronic components.

Take precautions during furnace installation and service
to protect the furnace’s electronic controls. Precautions

will help to avoid control exposure to electrostatic

discharge by putting the furnace, the control and the
technician at the same electrostatic potential. Neutralize
electrostatic charge by touching hand and all tools on
an unpainted unit surface, such as the gas valve or
blower deck, before performing any service procedure.

Figure 54. Interior Make-Up Box Installation

Figure 55. Interior Make-Up Box Installation

The unit is equipped with a eld makeup box. The makeup
box may be installed on the exterior of the right side of

the furnace to facilitate installation. Seal unused openings
on left side with plugs removed from right side. Secure

the excess wire to the existing harness to protect it from

damage.

Refer to Figure 65 for eld wiring and Figure 64 for

schematic wiring diagram and troubleshooting.

1. The power supply wiring must meet Class I restrictions.
Protected by either a fuse or circuit breaker, select
circuit protection and wire size according to unit
nameplate.

NOTE: Unit nameplate states maximum current draw.
Maximum over current protection allowed is shown in
Table 11.

2. Holes are on both sides of the furnace cabinet to
facilitate wiring.

3. Install a separate (properly sized) disconnect switch

near the furnace so that power can be turned o󰀨 for

servicing.

Capacity

070 15

090, 110 20

Maximum Over-Current

Protection (Amps)

Table 11.

4. Before connecting the thermostat, check to make sure
the wires will be long enough for servicing at a later
date. Make sure that thermostat wire is long enough to
facilitate future removal of blower for service.

5. Complete the wiring connections to the equipment.

Use the provided unit wiring diagram and the eld

wiring diagram shown in Figure 64. Use 18 gauge
wire or larger that is suitable for Class II rating for
thermostat connections.

6. Electrically ground the unit according to local codes or,
in the absence of local codes, according to the current
National Electric Code (ANSI/NFPA No. 70). A green

ground wire is provided in the eld make-up box.

NOTE: This furnace contains electronic components
that are polarity sensitive. Make sure that the furnace
is wired correctly and is properly grounded.

7. One line voltage “ACC” 1/4” spade terminal is provided
on the furnace integrated control. Any electronic air
cleaner or other accessory rated up to one amp can
be connected to this terminal with the neutral leg of the
circuit being connected to one of the provided neutral
terminals. This terminal is energized when the indoor
blower is operating.

8. One line voltage “HUM” 1/4” spade terminal is provided

on the furnace integrated control. Any humidier rated

up to one amp can be connected to this terminal
with the neutral leg of the circuit being connected to
one of the provided neutral terminals. This terminal
is energized in the heating mode whenever the
combustion air inducer is operating.

9. Install the room thermostat according to the instructions
provided with the thermostat. If the furnace is being
matched with a heat pump, refer to the instruction
packaged with the dual fuel thermostat.

508405-01Page 36 of 53 Issue 2332

Indoor Blower Speeds

1. When the thermostat is set to “FAN ON,” the indoor

blower will run continuously at approximately 50%

of the second stage cooling speed when there is no
cooling or heating demand. See Table 19 for allowable
continuous circulation speeds.

2. When this unit is running in the heating mode, the
indoor blower will run on the heating speed designated
by the positions of DIP switches 1 (A,B,C,D) of the

HEAT jumper plug. When the heat demand is satised,

the indoor blower will continue to run at the low stage
heat cfm for the duration of the user-selected heat

blower o󰀨 delay. The user can select one of the four
preset heat blower o󰀨 delays (60/90/120/180 sec) by

repositioning the movable shunt on the 5-pin header
on the ignition control.

Electrical Wiring

WARNING

Risk of electrical shock. Disconnect electrical power
at the circuit breaker or service panel before making
electrical connections. Failure to disconnect power
supplies can result in property damage, personal injury,
or death.

The furnace must be grounded and wired in accordance
with local codes or, in the absence of local codes, with the
National Electrical Code ANSI/NFPA No. 70 (latest edition)
and/or CSA C22.1 Electrical Code (latest edition) if an

external electrical source is utilized.

60

Heat Blower OFF
Delay Moveable

90

Shunt

P4

120

180

Figure 56. Heat Blower O󰀨 Delay Moveable Shunt

3. When there is a cooling demand, the indoor blower will
run on the cooling speed designated by the positions
of DIP switches (A, B, C, D) of the COOL jumper plug.
See Figure 58.

Generator Use - Voltage Requirements

The following requirements must be kept in mind when
specifying a generator for use with this equipment:

• The furnace requires 120 volts ± 10% (Range: 108
volts to 132 volts).

• The furnace operates at 60 Hz ± 5% (Range: 57 Hz
to 63 Hz).

• The furnace integrated control requires both polarity
and proper ground. Both polarity and proper grounding
should be checked before attempting to operate the
furnace on either permanent or temporary power.

• Generator should have a wave form distortion of less
than 5% THD (Total Harmonic Distortion).

In all instances, other than wiring for the thermostat,
the wiring to be done and any replacement of wire shall
conform with the temperature limitation for Type T wire
–63°F (35°C) rise.

Connect a su󰀩ciently sized wire with ground to the

furnace’s line voltage connections and ground wire. Refer
to the furnace rating plate for electrical characteristics

to be used in sizing eld supply wiring and overcurrent

protection.

The line voltage supply should be routed through a readily
accessible disconnect located within sight of the furnace. A

junction box on the furnace side panel is provided for line

voltage connections. Refer to the furnace wiring diagram

for specic connection information.

Proper polarity of the supply connections (“HOT” and
“NEUTRAL”) must be observed to ensure that safety
controls provide the protection intended.

A connection to the unit’s ground wire and actual earth
ground (typically a ground stake or buried steel pipe) must
be maintained for proper operation.

Thermostat

Install a room thermostat according to the instructions
furnished with it. Select a location on an inside wall that
is not subject to drafts, direct sunshine, or other heat
sources. The initial heat anticipator setting should be equal
to the total current draw of the control circuit. Low voltage
thermostat connections are to be made to the integrated
ignition/blower control board as indicated on the wiring
diagram.

508405-01 Page 37 of 53Issue 2332

NOTE: The automatic heat staging option allows a single
stage thermostat to be used with two stage furnace models.
To activate this option, move the jumper pin (see Figure 57)
to desired setting (5 minutes or 10 minutes). The furnace
will start on 1st stage heat and stay at 1st stage heat for
the duration of the selected time before switching to 2nd
stage heat. W1 on the control board must be connected to
W1 on the thermostat.

Figure 57. Automatic Heat Staging Jumper

Humidier

Terminals are provided on the integrated ignition/blower

control board for connection to a 120-volt humidier. The

“HUM” terminal is energized whenever the thermostat

calls for heat. See the furnace wiring diagram for specic

connection information.

Electronic Air Cleaner

Terminals are provided on the integrated ignition/blower
control board for connection of a 120-volt electronic air
cleaner. The “ACC” terminal is energized whenever the
thermostat calls for heat, cooling, or continuous blower. See

furnace wiring diagram for specic connection information.

Active Dehumidication

To achieve additional dehumidication, clip the jumper

wire located below the DEHUM terminal on the integrated
ignition/blower control board and connect a humidity
control that opens on humidity rise to the DEHUM and
R terminals. The DEHUM terminal on the control board
must be connected to the normally closed contact of the
humidity control so that the board senses an open circuit
on high humidity. In this setup, the variable speed motor

will operate at a 30% reduction in the normal cooling airow
rate when there is a call for dehumidication.

Both the passive and active dehumidication methods

described above can be utilized on the same furnace.

Circulating Airow Adjustments

Cooling Mode

The units are factory set for the highest airow for each
model. Adjustments can be made to the cooling airow

by repositioning the jumper plug marked COOL – A, B, C,
D (see Figure 58). To determine what CFM the motor is
delivering at any time, count the number of times the amber

LED on the control board ashes. Each ash signies 100
CFM; count the ashes and multiply by 100 to determine
the actual CFM delivered (for example: 10 ashes x 100 =

1000 CFM).

Variable Speed Features

This furnace is equipped with a variable speed circulation

air blower motor that will deliver a constant airow within a
wide range of external static pressures. Other features of

this variable speed motor include:

Soft Start

The variable speed motor will slowly ramp up to normal
operating speed. This minimizes noise and increases
comfort by eliminating the initial blasts of air encountered
with standard motors.

Soft Stop

At the end of a cooling or heating cycle, the variable speed

motor will slowly ramp down after a short blower “o󰀨” delay.

If continuous blower operation has been selected, the
variable speed motor will slowly ramp down until it reaches

the airow for that mode.

Passive and Active Dehumidication

Passive Dehumidication

For situations where humidity control is a problem, a

dehumidication feature has been built into the variable

speed motor. At the start of each cooling cycle, the variable

speed motor will run at 82% of the rated airow for 7.5

minutes. After 7.5 minutes has elapsed, the motor will

increase to 100% of the rated airow.

Heating Mode

These units are factory set to run at the middle of the
heating rise range as shown on the unit rating plate. If
higher or lower rise is desired, reposition the jumper plug
marked HEAT - A, B, C, D (see Figure 58) . To determine
what CFM the motor is delivering at any time, count the
number of times the amber LED on the control board

ashes. Each ash signies 100 CFM; count the ashes

and multiply by 100 to determine the actual CFM delivered

(for example: 10 ashes x 100= 1000.

Adjust Tap

Airow amounts may be increased or decreased by 10%

by moving the ADJUST jumper plug (see Figure 58) from
the NORM position to the (+) or (-) position. Changes to the

ADJUST tap will a󰀨ect both cooling and heating airows.

The TEST position on the ADJUST tap is not used.

Continuous Blower Operation

The comfort level of the living space can be enhanced
when using this feature by allowing continuous circulation
of air between calls for cooling or heating. The circulation

of air occurs at half the full cooling airow rate.

To engage the continuous blower operation, place the
fan switch on the thermostat into the ON position. A call
for fan from the thermostat closes R to G on the ignition
control board. The control waits for a 1 second thermostat
debounce delay before responding to the call for fan by
ramping the circulating blower up to 38% of the cooling

508405-01Page 38 of 53 Issue 2332

speed. When the call for continuous fan is satised, the

control immediately ramps down the circulating blower.

lockout. Lockout may be manually reset by removing
power from the control for more than 1 second or removing
the thermostat call for heat for more than 3 seconds.

If during a heating cycle the limit control senses an
abnormally high temperature and opens, the control board
de-energizes the gas valve and the combustion blower
while the circulating blower runs at 1st stage heat speed.
The circulating blower remains energized until the limits
are closed.

Fan On

When the thermostat is set for continuous fan operation
and there is no demand for heating or cooling, a call for fan
closes the R to G circuit and the circulating blower motor
runs at 38% of the selected cooling CFM until switched

o󰀨. When the call for fan is turned OFF, the control de-

energizes the circulating blower.

Figure 58. ADJUST, HEAT, and COOL Taps on

Integrated Ignition/Blower Control Board

Sequence of Operation

Heating

On a call for heat from the room thermostat, the control

board performs a 1 second self check. Upon conrmation

that the pressure switch contacts are in an open position,
the control energizes the combustion blower on high
speed. The control then checks for adequate combustion

air by making sure the low-re pressure switch contacts

are closed.

The igniter energizes and is allowed to warm up for 20
seconds before the gas valve energizes on 1st stage

and burners ignite. 45 seconds after the control conrms

ignition has occurred, the control drops the combustion
blower to low speed.

The circulating blower operates at full 1st stage heat

speed until either the heat call is satised or the thermostat

initiates a call for 2nd stage heat. On a call for 2nd stage
heat, the control energizes the circulating air blower on full
CFM 2nd stage heat.

If the automatic heat staging option is being used the
furnace does not switch to 2nd stage heat in response
to a call from the thermostat but instead operates at 1st
stage heat for the duration of the selected time before
automatically switching to 2nd stage heat.

When the call for heat is satised, the gas valve and

combustion air blower shut down. The control board shuts

o󰀨 the gas valve and runs the combustion blower for an

additional 15 seconds. The circulating air blower continues

to run for selected blower o󰀨 delay time (60/90/120/180
sec) before ramping down and shutting o󰀨.

In the event the unit loses ignition, the control will attempt

to recycle up to ve times before it goes into a 1 hour

Cooling

The unit is set up at the factory for single stage cooling. For
two stage cooling operation, clip the jumper wire located
between the Y to Y2 terminals on the integrated ignition/
blower control board.

If the active dehumidication feature is enabled, the

circulating blower runs at 70% of the selected cooling

speed as long as there is a call for dehumidication.

WARNING

The system must not be in either the passive or active

dehumidication mode when charging a cooling system.

Single Stage Cooling

A call for cooling from the thermostat closes the R to Y
circuit on the integrated ignition/blower control board. The
control waits for a 1-second delay before energizing the
circulating blower to 82% of the selected cooling CFM

(passive dehumidication mode). After 7.5 minutes, the

circulating blower automatically ramps up to 100% of

the selected cooling airow. When the call for cooling is
satised, the circulating blower ramps down to continuous

fan cfm (38% of high stage cooling) for 45 seconds before
completely shutting down the blower.

Two Stage Cooling

A call for 1st stage cooling from the thermostat closes the
R to Y circuit on the control board. The control waits for a
1-second delay before energizing the circulating blower.

The blower motor runs at 57% of the selected air ow
for the rst 7.5 minutes of the 2nd stage cooling demand
(passive dehumidication mode). After 7.5 minutes, the
blower motor runs at 70% of the selected cooling air ow
until 1st stage cooling demand is satised.

508405-01 Page 39 of 53Issue 2332

A call for 2nd stage cooling from the thermostat closes
the R to Y2 circuit on the control board. The blower motor

ramps up to 100% of the selected cooling air ow. When

the demand for cooling is met, the blower ramps down

to Y1 until satised, then ramps down to continuous fan

cfm (38% of high stage cooling) for 45 seconds before
completely shutting down the blower.

Heat Pump

For heat pump operation, clip the jumper wire located
below the O terminal on the integrated ignition/blower
control board. In heat pump mode, a call for heat will
result in the circulating air blower operating at the selected

cooling airow after a brief ramp-up period.

Control Diagnostics

Troubleshooting

Make the following visual checks before troubleshooting:

1. Check to see that the power to the furnace and the
integrated ignition/blower control board is ON.

2. The manual shuto󰀨 valves in the gas line to the furnace
must be open.

3. Make sure all wiring connections are secure.

4. Review the Sequence of Operation.

Start the system by setting thermostat above room
temperature. Observe system response. Then use the
information provided in this section to check the system
operation.

CFM LED

On models equipped with a variable speed motor, an amber
LED is provided on the control board to display CFM. To
determine what CFM the motor is delivering at any time,

count the number of times the amber LED ashes. Each
ash signies 100 CFM; count the ashes and multiply by
100 to determine the actual CFM delivered (for example:
10 ashes x 100 = 1000 CFM).

LED Status Fault Description

LED O󰀨

LED On Normal operation

1 Flash Flame present with gas valve o󰀨

2 Flashes Pressure switch closed with inducer o󰀨

3 Flashes

4 Flashes

5 Flashes Not used

6 Flashes Pressure switch cycle lockout

7 Flashes Lockout due to no ignition

8 Flashes

9 Flashes Incorrect polarity and phasing

No power to control or control
hardware fault detected

Pressure switch open with inducer
energized

Primary Limit, Secondary Limit, or Roll­Out switch open

Lockout due to too many ame

dropouts

Table 12. Failure Codes - Red LED

The furnace has a built-in, self-diagnostic capability. If a
system problem occurs, a fault code is shown by a red LED
on the control board. The control continuously monitors its
own operation and the operation of the system. If a failure

occurs, the LED will indicate the failure code. The ash

codes are presented in Table 12.

Fault Code History Button

The control stores the last ve fault codes in memory. A

push button switch is located on the control. When the
push button switch is pressed and released, the control

ashes the stored fault codes. The most recent fault code
is ashed rst; the oldest fault code is ashed last. To

clear the fault code history, press and hold the push button
switch in for more than 5 seconds before releasing.

High Heat State LED

On models, a green LED is provided on the control board
to indicate high heat state (see Table 13).

LED Status Description

LED O󰀨 No demand for high heat

LED On High heat demand, operating normally

LED Flashing

High heat demand, high pressure
switch not closed

Table 13. High Heat State - Green LED

508405-01Page 40 of 53 Issue 2332

W1/W2

w1 w2

W2

CALL

W1

100%**

100%*

***min

100%*

w1

CALL

*Percentage of Low Fire CFM
** Percentage of High Fire CFM
*** User-Selected Heat Blower OFF Delay

Figure 59. Indoor Blower Operation - 1st Stage-2nd Stage (W1/W2) Heat Call

w2

***min

100%*

W2 - High Heat Demand Present

w2 - High Heat Demand Satisfied

*Percentage of Low Fire CFM
** Percentage of High Fire CFM
*** User-Selected Heat Blower OFF Delay

OFF

***min

100%*

W1 - Heat Demand Present

w1 - Heat Demand Satisfied

W2 - High Heat Demand Present

w2 - High Heat Demand Satisfied

OFF

y

100%*

45
sec
38%

OFF

CALL

Y

7.5 minutes

82%*

Y - Heat Demand Present

y - Heat Demand Satisfied

*Percentage of High Stage Cooling CFM

Figure 62. Indoor Blower Operation - Single Stage

Cooling

Figure 60. Indoor Blower Operation - High Heat (W2)

Call

gG

38%*

G - Fan Switch ON

g - Fan Switch OFF

CALL

*Percentage of High Stage Cooling CFM

Figure 61. Indoor Blower Operation - Call for Fan

OFF

Y1

Y1/Y2

7.5

Y1 y2

100%*

y1

min.

70%*

CALL

57%*

Y1 - 1st Stage Cool Demand Present

y1 - 1st Stage Cool Demand Satisfied

Y2 - 2nd Stage Cooling Demand Present

y2 - 2nd Stage Cooling Demand Satisfied

*Percentage of High Stage Cooling

45 sec
38%*

y1

Figure 63. Indoor Blower Operation - Two Stage

Cooling

70%*

45 sec
38%*

OFF

508405-01 Page 41 of 53Issue 2332

L1 HOT

120/1

NEUTRAL

/60

INTERLOCK

SWITCH

CHOKE
(IF USED)

ROLLOUT

SWITCH

ROLLOUT

SWITCH
(IF USED)

120V

24V

FP

IGN

IND HIGH

IND LOW

HUM

EAC

CIRCULATION
BLOWER

TRANSFORMER

MOTOR

TH

HLO

HPS1

LPS1

HLI

W1

MVH

MVL

IGNITION
CONTROL

W2

C

FLAME
SENSOR

HOT SURFACE
IGNITER

INDUCED DRAFT
BLOWER

MOTOR

HUMIDIFIER

AIR CLEANER

TR

2ND STAGE

1ST STAGE

GAS VALVE

G

Y

R

MOTOR

LIMIT

PRESSURE
SWITCH
(LOW)

WIRING SCHEMATIC

WARNING­ELECTRIC SHOCK HAZARD,CAN CAUSE INJURY
OR DEATH.UNIT MUST BE GROUNDED IN ACCORDANCE
WITH NATIONAL AND LOCAL CODES.

NOTE­IF ANY WIRE IN THIS APPLIANCE IS REPLACED,IT
MUST BE REPLACED WITH WIRE OF LIKE SIZE,

RATING, INSULATION THICKNESS, AND TERMINATION

Figure 64. Typical Field Wiring Diagram

PRESSURE

SWITCH

(HIGH)

W1W2YR
THERMOSTAT CONDENSER

G

LINE VOLTAGE FIELD INSTALLED
LINE VOLTAGE - FACTORY
CLASS II VOLTAGE FIELD WIRING
LOW VOLTAGE - FACTORY

GAS FIRED TWO STAGE
FURNACE

HEATING UNITS-GAS

Supersedes

508405-01Page 42 of 53 Issue 2332

WHITE

GRN/YLW

442

3

WHITE

RED

BLACK

1

3

1

2

RED

BLACK

5 PIN
CONNECTOR

INDUCED
DRAFT
BLOWER

S1
P1

1

2

3

4

5

PRESSURE
SWITCH (HIGH)

LIMIT

PARK 2

HI HEAT

LO HEAT

PINK

PUR

PRESSURE

SWITCH (LOW)

PINK

BLUE

FLAME
SENSOR

BLUE

YELLOW

WHT/PINK

BROWN

BLACK

BLACK

LINE

HUM

ROLLOUT

XFMR

CONT

HOT

EAC

BLUE

BROWN

BLACK

BLACK

COOL

PARK 1

EAC

CIRC

LINE

ROLLOUT

XFMR

HUM

NEUTRAL

HOT

NEUTRAL

GROUND

1

/60

120/1

GRN/YLW

INTERLOCK
SWITCH

WHITE

WHITE

GAS VALVE

PURPLE

H1 C

BROWN

YELLOW

M

ORANGE

2

2

BLACK

HOT SURFACE
IGNITOR

2 PIN

1

CONNECTOR

1

IGNITION

CONTROL

3 AMP

9

12

11

10

3

6

5

8

2

1

4

7

G

W2

W1

W2

W1

THERMOSTAT

YC Y2

R

G

YR

C

0

CONDENSER

DEHUM

WHITE

WHITE

WHITE

CIRCULATION
BLOWER

GRN

5 PIN
CONNECTOR

2345

1

RED

WHITE

BLACK

INPUT CHOKE
(IF USED)

CONNECTION DIAGRAM

1

PROPER POLARITY MUST BE OBSERVED FOR FIELD LINE
VOLTAGE SUPPLY. IGNITION CONTROL WILL LOCK OUT IF
POLARITY IS REVERSED

NOTES:

1. PRESS AND RELEASE FAULT CODE HISTORY BUTTON TO DISPLAY FAULT CODES. TO ERASE CODES, PRESS AND HOLD BUTTON

IN FOR MORE THAN 5 SECONDS

2. IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THE FURNACE MUST BE REPLACED, IT MUST BE REPLACED WITH WIRING

MATERIAL HAVING A TEMP. RATING OF AT LEAST 90°c.

3. DO NOT CONNECT C (COMMON) CONNECTION BETWEEN INDOOR UNIT AND THERMOSTAT EXCEPT WHEN REQUIRED BY THE

INDOOR THERMOSTAT. REFER TO THE THERMOSTAT INSTALLATION INSTRUCTIONS.

Figure 65. Typical Wiring Diagram

508405-01 Page 43 of 53Issue 2332

Testing for Proper Venting and Su󰀩cient Combustion Air for Non-Direct Vent Applications

1. Seal any unused openings in the venting system.

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.

After the gas furnace has been started, the following
test should be conducted to ensure proper venting and

su󰀩cient combustion air has been provided to the unit as
well as to other gas red appliances which are separately

vented.

If this furnace replaces a Category I furnace which was
commonly vented with another gas appliance, the size

of the existing vent pipe for that gas appliance must be
checked. Without the heat of the original furnace ue
products, the existing vent pipe is probably oversized for

the single water heater or other appliance. The vent should
be checked for proper draw with the remaining appliance.

The test should be conducted while all appliances (both
in operation and those not in operation) are connected to
the venting system being tested. If the venting system has
been installed improperly, or if provisions have not been

made for su󰀩cient amounts of combustion air, corrections

must be made as outlined in the previous section.

2. Visually inspect the venting system for proper size
and horizontal pitch. Determine there is no blockage

or restriction, leakage, corrosion, or other deciencies

which could cause an unsafe condition.

3. To the extent that it is practical, close all building doors
and windows and all doors between the space in
which the appliances connected to the venting system
are located and other spaces of the building.

4. Close replace dampers.

5. Turn on clothes dryers and any appliances not

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

6. Follow the lighting instruction to place the appliance
being inspected into operation. Adjust thermostat so
appliance will operate continuously.

7. Use the ame of a match or candle to test for spillage

of ue gases at the draft hood relief opening after 5

minutes of main burner operation.

8. If improper venting is observed during any of the
above tests, the venting system must be corrected or

su󰀩cient combustion/makeup air must be provided.

The venting system should be resized to approach the
minimum size as determined by using the appropriate

tables in appendix G in the current standards of the
National Fuel Gas Code ANSI-Z223.1/NPFA 54 in the

U.S.A., and the appropriate Natural Gas and Propane
appliances venting sizing tables in the current standard
of the CSA-B149 Natural Gas and Propane Installation
Codes in Canada.

9. After determining that each appliance remaining
connected to the common venting system properly
vents when tested as indicated in step 3, return doors,

windows, exhaust fans, replace dampers and any

other gas burning appliance to their previous condition
of use.

508405-01Page 44 of 53 Issue 2332

Unit Start-Up

FOR YOUR SAFETY READ BEFORE OPERATING

WARNING

Do not use this furnace if any part has been underwater.

A ood-damaged furnace is extremely dangerous.
Attempts to use the furnace can result in re or explosion.
Immediately call a qualied service technician to inspect

the furnace and to replace all gas controls, control
system parts, and electrical parts that have been wet or
to replace the furnace, if deemed necessary.

WARNING

Danger of explosion. Can cause injury or

product or property damage. Should the gas

supply fail to shut o󰀨 or if overheating
occurs, shut o󰀨 the gas valve to the furnace
before shutting o󰀨 the electrical power.

CAUTION

Before attempting to perform any service or
maintenance, turn the electrical power to unit OFF at
disconnect switch.

BEFORE LIGHTING the unit, smell all around the furnace

area for gas. Be sure to smell next to the oor because
some gas is heavier than air and will settle on the oor.

The gas valve on the unit is equipped with a gas control
switch (lever). Use only your hand to move switch. Never
use tools. If the switch will not move by hand, do not try to

repair it. Force or attempted repair may result in a re or
explosion.

2. Set the thermostat to initiate a heating demand.

3. Allow the burners to re for approximately 3 minutes.

4. Adjust the thermostat to deactivate the heating
demand.

5. Wait for the combustion air inducer to stop. Set the
thermostat to initiate a heating demand and again

allow the burners to re for approximately 3 minutes.

6. Adjust the thermostat to deactivate the heating demand
and wait for the combustion air inducer to stop. At this

point, the trap should be primed with su󰀩cient water to

ensure proper condensate drain operation.

WARNING

If you do not follow these instructions exactly, a re
or explosion may result causing property damage,

personal injury or death.

Gas Valve Operation

1. STOP! Read the safety information at the beginning
of this section.

2. Set the thermostat to the lowest setting.

3. Turn OFF all electrical power to the unit.

4. This furnace is equipped with an ignition device which
automatically lights the burners. Do not try to light the
burners by hand.

5. Remove the heating compartment access panel.

6. Move gas valve switch to OFF. See Figure 66.

7. Wait ve minutes to clear out any gas. If you then
smell gas, STOP! Immediately call your gas supplier
from a neighbor’s phone. Follow the gas supplier’s

instructions. If you do not smell gas go to next step.

8. Move gas valve switch to ON. See Figure 66.

Gas Valve Shown In “ON’ Position

Placing the Furnace into Operation

This furnace is equipped with an automatic hot surface
ignition system. Do not attempt to manually light burners
on this furnace. Each time the thermostat calls for heat, the
burners will automatically light. The ignitor does not get hot
when there is no call for heat on these units.

Priming Condensate Trap

The condensate trap should be primed with water prior
to start-up to ensure proper condensate drainage. Either

pour 10 . oz. (300 ml) of water into the trap, or follow

these steps to prime the trap:

1. Follow the lighting instructions to place the unit into
operation.

508405-01 Page 45 of 53Issue 2332

Figure 66.

9. Replace the heating compartment access panel.

10. Turn on all electrical power to the unit.

11. Set the thermostat to desired setting.

NOTE: When unit is initially started, steps 1 through
11 may need to be repeated to purge air from gas line.

12. If the appliance will not operate, follow the instructions

“Turning O󰀨 Gas to Unit” and call your service

technician or gas supplier.

Turning O󰀨 Gas to Unit

1. Set the thermostat to the lowest setting.

2. Turn o󰀨 all electrical power to the unit if service is to
be performed.

3. Remove the heating compartment access panel.

4. Move gas valve switch to OFF.

5. Replace the heating compartment access panel.

Gas Pressure Adjustment

Gas Flow (Approximate)

Gas Meter Clocking Chart

Seconds for One Revolution

Capacity

070 55 110 136 272

090 41 82 102 204

110 33 66 82 164

Natural - 1000 btu/cu ft LP - 2500 btu/cu ft

Furnace should operate at least 5 minutes before checking

gas ow. Determine time in seconds for two revolutions of

gas through the meter. (Two revolutions assures a more
accurate time.) Divide by two and compare to time in Table

14. If manifold pressure matches Table 16 and rate is

incorrect, check gas orices for proper size and restriction.

Remove temporary gas meter if installed.

NOTE: To obtain accurate reading, shut o all other gas
appliances connected to meter.

Natural LP

1 cu ft

Dial

2 cu ft

Dial

Table 14.

1 cu ft

Dial

2 cu ft

Dial

one turn, connect a piece of 5/16” tubing and connect a
manometer to measure supply pressure.

NOTE: Shut unit o and remove manometer as soon as
an accurate reading has been obtained. Take care to re­tighten the 3/32 Hex screw.

Manifold Pressure Measurement

1. A manifold post located on the gas valve provides
access to the manifold pressure. See Figure 66. Back

out the 3/32 Hex screw one turn, connect a piece of

5/16” tubing and connect to a manometer to measure
manifold pressure.

2. Start unit and allow 5 minutes for unit to reach steady
state.

3. While waiting for the unit to stabilize, observe the

ame. Flame should be stable and should not lift from

burner. Natural gas should burn blue.

4. After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in
Table 16.

NOTE: Shut unit o and remove manometer as soon as
an accurate reading has been obtained. Take care to re­tighten the 3/32 Hex screw.

Proper Combustion

Furnace should operate minimum 15 minutes with correct

manifold pressure and gas ow rate before checking
combustion. Take combustion sample beyond the ue
outlet and compare to the tables below. The maximum
carbon monoxide reading should not exceed 100 ppm.

CO2% for Nat CO2% for L.P.

Capacity

Low Fire High Fire Low Fire High Fire

070 5.5 - 6.5 7.3 - 8.3 6.5 - 7.5 8.6 - 9.6

090 5.9 - 6.9 7.8 - 8.8 6.9 - 7.9 9.1 - 10.1

110 6.3 - 7.3 8.2 - 9.2 7.3 - 8.3 9.5 - 10.5

The maximum carbon monoxide reading should not exceed

100 ppm.

Supply Pressure Measurement

A pressure post on the inlet side of the gas valve provides

access to the supply pressure. Back out the 3/32 Hex screw

Manifold Pressure in w.g.

Capacity Gas

Natural 1.7 3.5 1.6 3.3 1.5 3.2 1.5 3.1 1.7 3.5 4.5 13.0

All Models

LP/Propane 4.5 10.0 4.2 9.4 4.0 9.1 3.9 8.9 4.5 10.0 11.0 13.0

0 - 4500 ft. 4501 - 5500 ft. 5501 - 6500ft. 6501 - 7500ft. 7501-10000ft.

Low
Fire

High

Fire

Low

Fire

High

Fire

Table 16. Manifold and Supply Line Pressure 0 - 10,000 ft.

Low

Fire

High

Fire

Low

Fire

Table 15.

High

Fire

Low

Fire

High

Fire

Supply Line

Pressure in

w.g.

0 - 10000 ft.

Min. Max.

508405-01Page 46 of 53 Issue 2332

Capacity

Natural to LP/

Propane

0 - 7500 ft

(0 - 2286m)

High Altitude Natural

Burner Orice Kit

7501 - 10000 ft
(2286 - 3048m)

High Altitude LP/

Propane Burner

Orice Kit

7501 - 10000 ft

(2286 - 3048m)

High Altitude Pressure Switch

4501 - 7500 ft

(1371 - 2286m)

7501 - 10000 ft
(2286 - 3048m)

070

090 14A54 14A53

110 25B93 14A45

*Conversion requires installation of a gas valve manifold spring which is provided with the gas conversion kit.

Pressure switch is factory set. No adjustment necessary. All models use the factory-installed pressure switch from 0-4500 feet (0-1371 m).

11K48 *51W01 11K47

14A48 14A54

Table 17. Conversion Kit Fan Pressure Switch Requirements at Varying Altitudes

High Altitude Information

NOTE: In Canada, certication for installations at

elevations over 4500 feet (1371 m) is the jurisdiction of

the temperature. Decrease the blower speed to increase
the temperature rise. Failure to adjust the temperature rise
may cause erratic limit operation.

local authorities.

Fan Control

Units may be installed at altitudes up to 4,500 ft. above
sea level without manifold adjustment. Units installed
at altitude of 4,501 - 10,000 feet (1371 to 3048 m) may
require a pressure switch change which can be ordered

The fan ON time of 30 seconds is not adjustable. The fan
OFF delay (amount of time that the blower operates after

the heat demand has been satised) is 120 seconds and

is not adjustable.

separately. Table 17 lists conversion kit and pressure
switch requirements at varying altitudes.

The combustion air pressure switch is factory-set and
requires no adjustment.

NOTE: A natural to LP/propane gas changeover kit is
necessary to convert this unit. Refer to the changeover kit
installation instruction for the conversion procedure.

Thermostat Heat Anticipation

Set the heat anticipator setting (if adjustable) according to
the amp draw listed on the wiring diagram that is attached
to the unit.

Electrical

1. Check all wiring for loose connections.

2. Check for the correct voltage at the furnace (with

Other Unit Adjustments

Primary Limit

The primary limit is located on the heating compartment
vestibule panel. This limit is factory set and requires no
adjustment.

Flame Rollout Switches (Two)

These manually reset switches are located on the front of

the burner box. These limits are factory set and require no

adjustment.

Pressure Switches

The pressure switches are located in the heating

compartment on the cold end header box. These switches

furnace operating). Correct voltage is 120 VAC ± 10%.

3. Check amp–draw on the blower motor with the blower
compartment access panel in place.

Motor Nameplate__________Actual__________

Electronic Ignition

The integrated control has an added feature of an internal
Watchguard control. The feature serves as an automatic
reset device for integrated control lockout caused by
ignition failure. This type of lockout is usually due to low
gas line pressure. After one hour of continuous thermostat
demand for heat, the Watchguard will break and remake
thermostat demand to the furnace and automatically reset
the integrated control to begin the ignition sequence.

check for proper combustion air inducer operation before
allowing ignition trial. The switches are factory set and
must not be adjusted.

Temperature Rise

After the furnace has been started and supply and return
air temperatures have been allowed to stabilize, check
the temperature rise. If necessary, adjust the blower
speed to maintain the temperature rise within the range
shown on the unit nameplate. See Table 18 for allowable
heating speeds. Increase the blower speed to decrease

Exhaust and Air Intake Pipe

1. Check exhaust and air intake connections for tightness
and to make sure there is no blockage.

2. Is pressure switch closed? Obstructed exhaust pipe

will cause unit to shut o󰀨 at pressure switch. Check

termination for blockages.

3. Obstructed pipe or termination may cause rollout

switches to open. Reset manual ame rollout switches
on burner box assembly if necessary.

508405-01 Page 47 of 53Issue 2332

Blower Performance

Model Temp Rise

97G2DF070BV16

Model Temp Rise

High Fire

35 - 65

Low Fire

20 - 50

Cooling

Stage

2nd Stage

1st Stage

High Fire

35 - 65

Low Fire

25 - 55

Speed

Adjustment

+ 1110 1305 1430 1700

Normal 995 1175 1315 1520

- 880 1055 1170 1365

+ 860 1020 1140 1340

Normal 795 910 1030 1230

- 680 825 910 1085

Speed

Adjustment

+ 1110 1340 1575 1800

Normal 995 1230 1420 1650

- 880 1085 1290 1460

+ 740 915 1055 1255

Normal 660 820 940 1120

- 575 735 850 995

Speed

Adjustment

+ 1395 1555 1695 1825

Normal 1275 1395 1585 1670

- 1145 1265 1405 1525

+ 1130 1230 1365 1475

Normal 1040 1130 1250 1340

- 910 1025 1130 1210

Setting “D” Setting “C” Setting “B” Setting “A”

Setting “D” Setting “C” Setting “B” Setting “A”

Setting “D” Setting “C” Setting “B” Setting “A”

Heating CFM @ 0 - 0.8” w.c.

Cooling CFM @ 0 - 0.8” w.c.

Heating CFM @ 0 - 0.8” w.c.

97G2DF090CV20

Cooling

Stage

2nd Stage

1st Stage

Speed

Adjustment

+ 1335 1600 1750 1980

Normal 1225 1450 1630 1830

- 1120 1270 1450 1660

+ 955 1115 1265 1450

Normal 855 1005 1150 1285

- 750 890 1060 1170

Setting “D” Setting “C” Setting “B” Setting “A”

Cooling CFM @ 0 - 0.8” w.c.

508405-01Page 48 of 53 Issue 2332

Model Temp Rise

High Fire

35 - 65

Low Fire

20 - 50

Speed

Adjustment

+ 1595 1795 1955 2140

Normal 1450 1615 1795 1975

- 1290 1460 1610 1795

+ 1165 1305 1465 1625

Normal 1055 1185 1315 1475

- 930 1070 1180 1320

Setting “D” Setting “C” Setting “B” Setting “A”

Heating CFM @ 0 - 0.8” w.c.

97G2DF110CV20

Model Number Speed Adjust Setting "D" Setting "C" Setting "B" Setting "A"

97G2DF070BV16

97G2DF090CV20

Cooling

Stage

2nd Stage

1st Stage

+10% Allowed Allowed Allowed Allowed

Norm Allowed Allowed Factory Setting Allowed

-10% Allowed Allowed Allowed Allowed

+10% Allowed Allowed Allowed Allowed

Norm Allowed Allowed Factory Setting Allowed

Speed

Adjustment

+ 1335 1585 1790 2010

Normal 1220 1440 1630 1865

- 1100 1275 1475 1680

+ 920 1095 1265 1440

Normal 830 965 1130 1290

- 735 860 1035 1155

Allowable Heating Speeds

Setting “D” Setting “C” Setting “B” Setting “A”

Cooling CFM @ 0 - 0.8” w.c.

-10% Allowed Allowed Allowed Allowed

+10% Allowed Allowed Allowed Allowed

97G2DF110CV20

Norm Allowed Allowed Factory Setting Allowed

-10% Allowed Allowed Allowed Allowed

Table 18.

Allowable Circulation Speeds

Model Number 38% of Second Stage Cooling

All Models Factory Setting

Table 19.

508405-01 Page 49 of 53Issue 2332

Service

3. Check amp-draw on the blower motor with the blower
compartment access panel in place.

Motor Nameplate__________Actual__________

WARNING

ELECTRICAL SHOCK, FIRE, OR EXPLOSION

HAZARD.

Failure to follow safety warnings exactly could result in

dangerous operation, serious injury, death or property
damage.

Improper servicing could result in dangerous operation,
serious injury, death, or property damage.

Before servicing, disconnect all electrical power to
furnace.

When servicing controls, label all wires prior to
disconnecting. Take care to reconnect wires correctly.
Verify proper operation after servicing.

At the beginning of each heating season, system should

be checked as follows by a qualied service technician:

Blower

Check the blower wheel for debris and clean if necessary.

The blower motors are pre-lubricated for extended bearing

life. No further lubrication is needed.

WARNING

The blower access panel must be securely in place
when the blower and burners are operating. Gas fumes,

which could contain carbon monoxide, can be drawn

into living space resulting in personal injury or death.

Filters

All air lters are installed external to the unit. Filters should
be inspected monthly. Clean or replace the lters when

necessary to ensure proper furnace operation. Table 3

lists recommended lter sizes. A lter must be in place

whenever the unit is operating.

Exhaust and Air Intake Pipes

Check the exhaust and air intake pipes and all connections

for tightness and to make sure there is no blockage.

NOTE: After any heavy snow, ice or frozen fog event the
furnace vent pipes may become restricted. Always check
the vent system and remove any snow or ice that may be
obstructing the plastic intake or exhaust pipes.

Electrical

1. Check all wiring for loose connections.

2. Check for the correct voltage at the furnace (furnace
operating). Correct voltage is 120 VAC ± 10%.

Winterizing and Condensate Trap Care

1. Turn o󰀨 power to the furnace.

2. Have a shallow pan ready to empty condensate water.

3. Remove the clean out cap from the condensate trap
and empty water. Inspect the trap then reinstall the
clean out cap.

Cleaning Heat Exchanger

If cleaning the heat exchanger becomes necessary,

follow the below procedures and refer to Figure 1 when
disassembling unit. Use papers or protective covering in

front of furnace while removing heat exchanger assembly.

1. Turn o󰀨 electrical and gas supplies to the furnace.

2. Remove the furnace access panels.

3. Disconnect the wires from the gas valve.

4. Remove gas supply line connected to gas valve.
Remove gas valve/manifold assembly.

5. Remove sensor wire from sensor. Disconnect 2 pin
plug from the ignitor.

6. Disconnect wires from ame rollout switches.

7. Loosen clamps at vent elbow. Disconnect condensate

drain tubing from ue collar and remove the vent

elbow.

8. Remove four burner box screws at the vestibule panel

and remove burner box. Set burner box assembly

aside.

NOTE: If necessary, clean burners at this time. Follow
procedures outlined in Burner Cleaning section.

9. Mark and disconnect all combustion air pressure

tubing from cold end header collector box.

10. Mark and remove wires from pressure switches.
Remove pressure switches. Keep tubing attached to
pressure switches.

11. Disconnect the plug from the combustion air inducer.
Remove two screws which secure combustion air

inducer to collector box. Remove combustion air

inducer assembly. Remove ground wire from vest
panel.

12. Remove electrical junction box from the side of the
furnace.

13. Mark and disconnect any remaining wiring to heating
compartment components. Disengage strain relief
bushing and pull wiring and bushing through the hole
in the blower deck.

14. Remove the primary limit from the vestibule panel.

15. Remove two screws from the front cabinet ange at
the blower deck. Spread cabinet sides slightly to allow

clearance for removal of heat exchanger.

508405-01Page 50 of 53 Issue 2332

16. Remove screws along vestibule sides and bottom

which secure vestibule panel and heat exchanger

assembly to cabinet. Remove two screws from blower

rail which secure bottom heat exchanger ange.
Remove heat exchanger from furnace cabinet.

17. Back wash heat exchanger with soapy water solution
or steam. If steam is used it must be below 275°F
(135°C).

18. Thoroughly rinse and drain the heat exchanger. Soap
solutions can be corrosive. Take care to rinse entire
assembly.

19. Reinstall heat exchanger into cabinet making sure

that the clamshells of the heat exchanger assembly

are resting on the support located at the rear of the
cabinet. Remove the indoor blower to view this area
through the blower opening.

20. Resecure the supporting screws along the vestibule
sides and bottom to the cabinet. Reinstall blower and
mounting screws.

21. Reinstall cabinet screws on front ange at blower
deck.

22. Reinstall the primary limit on the vestibule panel.

23. Route heating component wiring through hole in
blower deck and reinsert strain relief bushing.

24. Reinstall electrical junction box.

25. Reinstall the combustion air inducer. Reconnect the
combustion air inducer to the wire harness.

26. Reinstall pressure switches and reconnect pressure
switch wiring.

27. Carefully connect combustion air pressure switch
hosing from pressure switches to proper stubs on cold

end header collector box.

28. Reinstall condensate trap.

29. Reconnect exhaust piping and exhaust drain tubing.

30. Reinstall burner box assembly in vestibule area.

31. Reconnect ame rollout switch wires.

32. Reconnect sensor wire and reconnect 2-pin plug from
ignitor.

33. Secure burner box assembly to vestibule panel using

four existing screws. Make sure burners line up in

center of burner ports.

34. Reinstall gas valve manifold assembly. Reconnect gas
supply line to gas valve.

35. Reconnect wires to gas valve.

36. Replace the blower compartment access panel.

37. Refer to instruction on verifying gas and electrical
connections when re-establishing supplies.

38. Follow lighting instructions to light and operate furnace

for 5 minutes to ensure that heat exchanger is clean

and dry and that furnace is operating properly.

39. Replace heating compartment access panel.

Cleaning the Burner Assembly

1. Turn o󰀨 electrical and gas power supplies to furnace.
Remove upper and lower furnace access panels.

2. Disconnect from the gas valve.

3. Remove the burner box cover.

4. Disconnect the gas supply line from the gas valve.
Remove gas valve/manifold assembly.

5. Mark and disconnect sensor wire from the sensor.
Disconnect 2 pin plug from the ignitor at the burner

box.

6. Remove four screws which secure burner box
assembly to vest panel. Remove burner box from the

unit.

7. Use the soft brush attachment on a vacuum cleaner
to gently clean the face of the burners. Visually
inspect the inside of the burners and crossovers for
any blockage caused by foreign matter. Remove any
blockage.

8. Reconnect the sensor wire and reconnect the 2 pin
plug to the ignitor wiring harness.

9. Reinstall the burner box assembly using the existing
four screws. Make sure that the burners line up in the
center of the burner ports.

10. Reinstall the gas valve manifold assembly. Reconnect
the gas supply line to the gas valve. Reinstall the

burner box cover.

11. Reconnect wires to gas valve.

12. Replace the blower compartment access panel.

13. Refer to instruction on verifying gas and electrical
connections when re-establishing supplies.

14. Follow lighting instructions to light and operate furnace

for 5 minutes to ensure that heat exchanger is clean

and dry and that furnace is operating properly.

15. Replace heating compartment access panel.

508405-01 Page 51 of 53Issue 2332

Planned Service

A service technician should check the following items
during an annual inspection. Power to the unit must be

shut o󰀨 for safety.

Fresh air grilles and louvers (on the unit and in the
room where the furnace is installed) - Must be open and
unobstructed to provide combustion air.

Burners - Must be inspected for rust, dirt, or signs of water.

Vent pipe - Must be inspected for signs of water, cracked,

damaged or sagging pipe, or disconnected joints.

Unit appearance - Must be inspected for rust, dirt, signs of
water, burnt or damaged wires, or components.

Blower access door - Must be properly in place and
provide a seal between the return air and the room where
the furnace is installed.

Return air duct - Must be properly attached and provide
an air seal to the unit.

Repair Parts List

Operating performance - Unit must be observed during

operation to monitor proper performance of the unit and
the vent system.

Combustion gases - Flue products must be analyzed and

compared to the unit specications.

Problems detected during the inspection may make it
necessary to temporarily shut down the furnace until the
items can be repaired or replaced.

Instruct the homeowners to pay attention to their
furnace. Situations can arise between annual furnace

inspections that may result in unsafe operation. For

instance, items innocently stored next to the furnace may

obstruct the combustion air supply. This could cause
incomplete combustion and the production of carbon

monoxide gas.

The following repair parts are available through Allied Air dealers. When ordering parts, include the complete furnace model
number listed on the CSA nameplate. All service must be performed by a licensed professional installer (or equivalent),
service agency, or gas supplier.

Cabinet Parts

• Heating Compartment Access Panel

• Blower Compartment Access Panel

• Top Cap

Control Panel Parts

• Transformer

• Integrated Control Board

• Door Interlock Switch

Blower Parts

• Blower Wheel

• Motor

• Motor Mounting Frame

• Motor Choke

• Blower Housing Cuto󰀨 Plate

Heating Parts

• Flame Sensor

• Heat Exchanger Assembly

• Gas Manifold

• Combustion Air Inducer

• Gas Valve

• Main Burner Cluster

• Main Burner Orices

• Pressure Switches

• Ignitor

• Primary Limit Control

• Flame Rollout Switches

508405-01Page 52 of 53 Issue 2332

Requirements for Commonwealth of Massachusetts

Modications to NFPA-54, Chapter 10

Revise NFPA-54 section 10.8.3 to add the following

requirements:

For all side wall, horizontally vented, gas-fueled equipment
installed in every dwelling, building or structure used in
whole or in part for residential purposes, including those
owned or operated by the Commonwealth and where the

side wall exhaust vent termination is less than seven (7)
feet above the nished grade in the area of the venting,

including but not limited to decks and porches, the following

requirements shall be satised:

1. INSTALLATION OF CARBON MONOXIDE
DETECTORS. At the time of installation of the side

wall, horizontally vented, gas-fueled equipment, the

installing plumber or gas tter shall observe that a
hard-wired carbon monoxide detector with an alarm
and battery backup is installed on the oor level where

the gas equipment is to be installed. In addition, the

installing plumber or gas tter shall observe that a
battery-operated or hard-wired carbon monoxide

detector with an alarm is installed on each additional
level of the dwelling, building or structure served by the
side wall, horizontally vented, gas-fueled equipment.
It shall be the responsibility of the property owner to

secure the services of qualied licensed professionals
for the installation of hard-wired carbon monoxide

detectors.

a. In the event that the side wall, horizontally vented,

gas-fueled equipment is installed in a crawl space

or an attic, the hard-wired carbon monoxide

detector with alarm and battery backup may be

installed on the next adjacent oor level.

b. In the event that the requirements of this subdivision

cannot be met at the time of completion of
installation, the owner shall have a period of thirty
(30) days to comply with the above requirements;
provided, however, that during said thirty (30)

day period, a battery-operated carbon monoxide

detector with an alarm shall be installed.

2. APPROVED CARBON MONOXIDE DETECTORS.

Each carbon monoxide detector as required in

accordance with the above provisions shall comply
with NFPA 720 and be ANSI/UL 2034 listed and IAS

certied.

3. SIGNAGE. A metal or plastic identication plate shall
be permanently mounted to the exterior of the building

at a minimum height of eight (8) feet above grade

directly in line with the exhaust vent terminal for the

horizontally vented, gas-fueled heating appliance or
equipment. The sign shall read, in print size no less
than one-half (1/2) inch in size, “GAS VENT DIRECTLY
BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS.”

4. INSPECTION. The state or local gas inspector of the
side wall, horizontally vented, gas-fueled equipment
shall not approve the installation unless, upon

inspection, the inspector observes carbon monoxide

detectors and signage installed in accordance with the
provisions of 248 CMR 5.08(2)(a) 1 through 4.

EXEMPTIONS: The following equipment is exempt
from 24 CMR 5.08(2)(a) 1 through 4:

1. The equipment listed in Chapter 10 entitled “Equipment
Not Required to Be Vented” in the most current edition
of NFPA 54 as adopted by the Board; and

2. Product Approved side wall, horizontally vented, gas­fueled equipment installed in a room or structure
separate from the dwelling, building or structure used
in whole or in part for residential purposes.

MANUFACTURER REQUIREMENTS - GAS EQUIPMENT

VENTING SYSTEM PROVIDED.

When the manufacturer of Product Approved side wall,
horizontally vented, gas-fueled equipment provides a
venting system design or venting system components
with the equipment, the instructions provided by the
manufacturer for installation of the equipment and the
venting system shall include:

1. Detailed instructions for the installation of the venting
system design or the venting system components: and

2. A complete parts list for the venting system design or
venting system.

MANUFACTURER REQUIREMENTS - GAS EQUIPMENT

VENTING SYSTEM NOT PROVIDED.

When the manufacturer of Product Approved sidewall,
horizontally vented, gas-fueled equipment does not

provide the parts for venting the ue gases, but identies

“special venting systems,” the following requirements shall

be satised by the manufacturer:

1. The referenced “special venting system” instructions
shall be included with the appliance or equipment
installation instructions; and

2. The “special venting systems” shall be Product
Approved by the Board, and the instructions for that
system shall include a parts list and detailed installation
instructions.

A copy of all installation instructions for all Product

Approved side wall, horizontally vented, gas-fueled

equipment, all venting instructions, all parts lists
for venting instructions, and/or all venting design
instructions shall remain with the appliance or
equipment at the completion of the installation.

508405-01 Page 53 of 53Issue 2332