Lennox A96DFMV User manual

506552-01 Page 1 of 52Issue 1034
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.
As with any mechanical equipment, personal injury can
result from contact with sharp sheet metal edges. Be
careful when you handle this equipment.
CAUTION
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.
WARNING
This manual must be left with the homeowner for future reference.
INSTALLATION INSTRUCTIONS
A96DFMV
Warm Air Gas Furnace
Downflow Air Discharge
Manufactured By
Allied Air Enterprises, Inc.
A Lennox International, Inc. Company
215 Metropolitan Drive
West Columbia, SC 29170
Unit Dimensions ............................................................ 2
Parts Arrangement ........................................................ 3
Gas Furnace ................................................................. 4
Shipping and Packing List ............................................ 4
Safety Information ......................................................... 4
Use of Furnace as a Construction Heater .................... 5
General ......................................................................... 6
Setting Equipment ........................................................ 6
Filters ............................................................................ 9
Duct System .................................................................. 9
Pipe and Fittings Specifications .................................. 10
Joint Cementing Procedure ........................................ 11
Venting Practices ........................................................ 12
Vent Piping Guidelines ................................................ 12
Gas Piping .................................................................. 20
TABLE OF CONTENTS
Electrical ..................................................................... 22
Integrated Control ....................................................... 29
Blower Motor Performance ......................................... 30
Unit Start Up ................................................................ 35
Gas Pressure Measurement ....................................... 36
High Altitude Information ............................................. 36
Proper Combustion ..................................................... 36
Other Unit Adjustments ............................................... 37
Heating Sequence of Operation ................................. 38
Service ........................................................................ 40
Planned Service .......................................................... 42
Integrated Control Diagnostic Codes .......................... 43
Configuring Unit Size Codes ....................................... 44
Troubleshooting .......................................................... 45
Repair Parts List ......................................................... 51
*506552-01*

506552-01Page 2 of 52 Issue 1034
Model Number
A
446
17-1/2
A96DFMV070B12S
BC
in. mm in. mm in. mm
416
16-3/8 406
16
A96DFMV090C12S
A96DFMV090C16S
A96DFMV090C20S
A96DFMV110C20S
533
21 505
19-7/8 495
19-1/2
D
in. mm
238
9-3/8
194
7-5/8
Unit Dimensions - inches (mm)
FRONT VIEW SIDE VIEW

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A96DFMV Exploded View
Figure 1

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A96DFMV Gas Furnace
The A96DFMV Category IV gas furnace is equipped with a
variable capacity, varable speed integrated control. Each
A96DFMV is shipped ready for installation in the Downflow
air discharge position.
The furnace is equipped for installation in natural gas
applications only. A changeover kit must be ordered for LP/
propane applications.
The A96DFMV must be installed only as a Direct Vent
gas central furnace
NOTE: In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors. See
Figure 2 for applications including roof termination.
Shipping and Packing List
1 - Assembled A96DFMV unit.
1 - Bag assembly containing the following:
3 - Wire nuts
1 - Snap bushing
1 - Snap Plug
1 - Wire tie
1 - Condensate trap
1 - Condensate trap cap
1 - Condensate trap cap clamp
1 - 3/8” NPT to 1/2” PVC fitting
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
Please refer to specification sheets for available accessories.
Safety Information
As with any mechanical equipment, personal injury can
result from contact with sharp sheet metal edges. Be
careful when you handle this equipment.
CAUTION
DANGER OF EXPLOSION!
DANGER
There are circumstances in which odorant used with LP/
Propane gas can lose its scent. In case of a leak, LP/
Propane gas will settle close to the floor and may be difficult
to smell. An LP/Propane leak detector should be installed
in all LP applications.
Use only the type of gas approved for use with this furnace.
Refer to unit nameplate.
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.
Installed Locations
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.
The furnace is designed for installation clearances to
combustible material as listed on the unit nameplate and in
the Tables 1 and 2. Accessibility and service clearances
must take precedence over fire protection clearances.
NOTE: For installation on combustible floors, the furnace
shall not be installed directly on carpeting, tile, or other
combustible material other than wood flooring.
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.
WARNING
Figure 2
DIRECT VENT INSTALLATION

506552-01 Page 5 of 52Issue 1034
For installation in a residential garage, the furnace must be
installed so that the burner(s) and the ignition source are
located no less than 18 inches (457 mm) above the floor.
The furnace must be located or protected to avoid physical
damage by vehicles. When a furnace is installed in a public
garage, hangar, or other building that has a hazardous
atmosphere, the furnace must be installed according to
recommended good practice requirements and current
National Fuel Gas Code or CSA B149 standards.
Note: Furnace must be adjusted to obtain a temperature
rise (100% percent capacity) within the range (s) specified
on the unit nameplate. Failure to do so may cause erratic
limit operation and may also result in premature heat
exchanger failure.
This A96DFMV furnace must be installed so that its electrical
components are protected from water.
Installed in Combination with a Cooling Coil
When this furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating compartment.
With a parallel flow arrangement, a damper (or other means
to control the flow of air) must adequately prevent chilled air
from entering the furnace. If the damper is manually
operated, it must be equipped to prevent operation of either
the heating or the cooling unit, unless it is in the full HEAT or
COOL setting. See Figure 3.
The A96DFMV furnace may be installed in alcoves, closets,
attics, basements, garages, and utility rooms.
This furnace design has not been approved for installation
in mobile homes, recreational vehicles, or outdoors.
Use of Furnace as Construction Heater
These units are not recommended for construction heater
during any phase of construction. Very low return air
temperature, harmful vapors and operation of the unit with
clogged or misplaced filters will damage the unit.
These units may be used for heating of buildings or structures
under construction, if the following conditions are met:
•The vent system must be permanently installed per these
installation instructions.
•A room thermostat must control the furnace. The use of
fixed jumpers that will provide continuous heating is not
allowed.
•The return air duct must be provided and sealed to the
furnace.
•Return air temperature range between 60°F (16°C) and
80°F (27°C) must be maintained.
•Air filters must be installed in the system and must be
maintained during construction.
When installed, this furnace must be electrically grounded
according to local codes. In addition, in the United States,
installation must conform with the current National Electric
Code, ANSI/NFPA No. 70. The National Electric Code (ANSI/
NFPA No. 70) is available from the following address:
National Fire Protection Association
1 Battery March Park
Quincy, MA 02269
NOTE: This furnace is designed for a minimum continuous
return air temperature of 60°F (16°C) or an intermittent
operation down to 55°F (13°C) dry blub for cases where a
night setback thermostat is used. Return air temperature
must not exceed 85°F (29°C)dry bulb.
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.
Do Not set thermostat below 60° F (16° C) in heating
mode. Setting thermostat below 60° F (16° C) reduces
the number of heating cycles. Damage to the unit may
occur that is not covered by the warranty.
CAUTION
Figure 3
Heating Unit Installed Parallel to Air Handler Unit

506552-01Page 6 of 52 Issue 1034
•Air filters must be replaced upon construction completion.
•The input rate and temperature rise must be set per the
furnace rating plate.
•One hundred percent (100%) outdoor air must be provided
for combustion air requirements during construction.
•The furnace heat exchanger, components, duct system,
air filters and evaporator coils must be thoroughly
cleaned following final construction cleanup.
•All furnace operating conditions (including ignition, input
rate, temperature rise and venting) must be verified
according to these installation instructions.
General
These units should not be installed in areas normally
subject to freezing temperatures.
CAUTION
In addition to the requirements outlined previously, the
following general recommendations should be considered
when installing one of these furnaces:
•Place the furnace as close to the center of the air
distribution system as possible. The furnace should also
be located close to the chimney or vent termination point.
•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
condensate drain system.
Installation – Setting Equipment
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, for proper operation. It is
recommended to tilt the unit slightly toward the drain to insure
proper drainage. See Figure 4.
Product Contains Fiberglass Wool.
Disturbing the insulation in this product during
installation, maintenance, or repair will expose you to
fiberglass wool. Breathing this may cause lung cancer.
(Fiberglass wool is known to the State of California to
cause cancer.)
Fiberglass wool may also cause respiratory, skin, and
eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets available
from address shown below, or contact your supervisor.
Allied Air Enterprises, Inc.
215 Metropolitan Drive
West Columbia, SC 29170
WARNING
Do not install the furnace on its front or its back. See
Figure 5. Do not connect the return air ducts to the
back of the furnace. Doing so will adversely affect the
operation of the safety control devices, which could
result in personal injury or death.
WARNING
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
Figure 5
SETTING EQUIPMENT
Unit must be level side to side in all applications for proper operation. A slight tilt
toward the drain is recommended for proper drainage.
Front
View
Side View
Figure 4

506552-01 Page 7 of 52Issue 1034
NOTE: The 1/2 hp blower motor used in this unit is equipped
with three flexible legs and one rigid leg. The rigid leg is
equipped with a shipping bolt and a flat white plastic washer
(rather than the rubber mounting grommet used with a flexible
mounting leg). The bolt and washer must be removed
before the furnace is placed into operation. After the
bolt and washer have been removed, the rigid leg will not
touch the blower housing.
Figure 6
1/2 HP BLOWER MOTOR
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or
alcove installations are shown in Figure 7.
The unit may be installed three ways in downflow
applications: on non-combustible flooring, on combustible
flooring using a base, or on a reverse flow cooling coil
cabinet. Do not drag the unit across the floor in the downflow
position. Flange damage will result.
Refer to Figure 7 for clearances in downflow applications.
Installation on Non-Combustible Flooring (Figure 8)
1. Cut floor opening keeping in mind clearances listed on
unit rating plate. Also keep in mind gas supply
connections, electrical supply, flue and air intake
connections and sufficient installation and servicing
clearances. See Table 1 for correct floor 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.
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.
WARNING
Improper installation of the furnace can result in personal
injury or death. Combustion and flue products must
never be allowed to enter the return air system or 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 fireplace or stove, etc. Fire, explosion, carbon
monoxide poisoning, personal injury and/or property
damage could result.
WARNING
Downflow Application Installation Clearances
* 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 and
vent pipe installation.
‡ The furnace may be Installed on a combustible wood floor if an
optional base is installed between the furnace and the combustible
floor.
Figure 7

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Figure 8
The furnace and combustible flooring base shall not be
installed directly on carpeting, tile, or other combustible
material other than wood flooring. units should not be
installed in areas normally subject to freezing
temperatures.
CAUTION
Figure 9
Installation on Combustible Flooring (Figure 9)
1. When unit is installed on a combustible floor, a downflow
combustible flooring base must be installed between the
furnace and the floor. The base must be ordered
separately. See Table 2 for opening size to cut in floor.
2. After opening is cut, set combustible flooring base into
opening.
3. Check fiberglass strips on combustible flooring base to
make sure they are properly glued and positioned.
4. Lower supply air plenum into combustible flooring base
until plenum flanges seal against fiberglass strips.
NOTE - Be careful not to damage fiberglass 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 (Figure 10)
NOTE: Downflow combustible flooring base is not used.
1. Refer to reverse flow coil installation instructions for
correctly sized opening in floor 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.
Non- Combustible Floor Opening Size
NOTE: Floor opening dimensions listed are 1/4 inch (6 mm) larger
than the unit opening. See dimension drawing on page 2.
Table 1
Combustible Flooring Base Opening Size
Table 2

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Return Air Opening - Downflow Units
Return air may be brought in only through the top opening
of a furnace installed in the downflow position. The following
steps should be taken when installing plenum:
1. Bottom edge of plenum should be flanged with a
hemmed edge (See figure 11 or 12).
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.
Figure 10
Figure 11
Figure 12
Filters
This unit is not equipped with a filter or rack. A field provided
filter is required for the unit to operate properly. Table 3 lists
recommended filter size.
A filter must be in place whenever the unit is operating.
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: Operation of this furnace in heating mode (indoor
blower operating at selected heating speed) with an external
static pressure which exceeds 0.8 inches w.c. may result in
erratic limit operation.
Return Air Plenum
Return air must not be drawn from a room where this furnace,
or any other gas fueled appliance (Le., water heater), or
carbon monoxide producing device (Le., wood fireplace) 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 flue products
can be pulled back down the vent pipe and into the room.
This reverse flow of the flue gas may result in incomplete
combustion and the formation of carbon monoxide gas. This
toxic gas might then be distributed throughout the house by
the furnace duct system.
Use fiberglass sealing strips, caulking, or equivalent sealing
method between the plenum and the furnace cabinet to
ensure a tight seal. If a filter is installed, size the return air
duct to fit the filter frame.
Table 3

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Pipe & Fittings Specifications
All pipe, fittings, 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 flowing and contain no lumps,
undissolved particles or any foreign matter that adversely
affects the joint strength or chemical resistance of the
cement. The cement shall show no gelation, stratification,
or separation that cannot be removed by stirring. Refer to
Table 4 for approved piping and fitting materials.
Use PVC primer and solvent cement or ABS solvent cement
meeting ASTM specifications, refer to Table 4. As an
alternate, use all purpose cement, to bond ABS, PVC, or
CPVC pipe when using fittings 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. Metal
or plastic strapping may be used for vent pipe hangers.
Uniformly apply a liberal coat of PVC primer for PVC
Canadian Applications Only - Pipe, fittings, primer and
solvent cement used to vent (exhaust) this appliance must
be certified to ULC S636 and supplied by a single
manufacturer as part of an approved vent (exhaust) system.
In addition, the first three feet of vent pipe from the furnace
flue collar must be accessible for inspection.
Table 5 lists the available exhaust termination kits.
Piping and Fittings Specifications
Table 4
Solvent cements for plastic pipe are flammable 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 fire hazard and to minimize breathing of
solvent vapors. Avoid contact of cement with skin and
eyes.
CAUTION
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 fittings
in the unit.
IMPORTANT