Lennox Allied Air A96UHMV User manual

506550-01 Page 1 of 66Issue 1230
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
Manufactured By
Allied Air Enterprises, LLC
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 .......................................................................... 11
Duct System ................................................................ 11
Pipe and Fittings Specifications .................................. 12
Joint Cementing Procedure ........................................ 13
Venting Practices ........................................................ 14
Vent Piping Guidelines ................................................ 14
Gas Piping .................................................................. 25
TABLE OF CONTENTS
Electrical ..................................................................... 28
Integrated Control ....................................................... 34
Blower Motor Performance ......................................... 38
Unit Start Up ................................................................ 49
Gas Pressure Measurement ....................................... 50
High Altitude Information............................................. 50
Proper Combustion ..................................................... 50
Other Unit Adjustments............................................... 51
Heating Sequence of Operation ................................. 52
Service ........................................................................ 54
Planned Service .......................................................... 56
Integrated Control Diagnostic Codes .......................... 57
Configuring Unit Size Codes ....................................... 58
Troubleshooting .......................................................... 59
Repair Parts List ......................................................... 65
This manual must be left with the homeowner for future reference.
INSTALLATION INSTRUCTIONS
A96UHMV
Warm Air Gas Furnace
Upflow/Horizontal Left and Right Air Discharge
*P506550-01*
(P) 506550-01

506550-01Page 2 of 66 Issue 1230
Model Number
A
446
17-1/2
A96UHMV070B12S
BC
in. mm in. mm in. mm
416
16-3/8 406
16
A96UHMV090C12S
A96UHMV090C16S
A96UHMV090C20S
A96UHMV110C20S
A96UHMV135D20S
533
21 505
19-7/8 495
19-1/2
622
24-1/2 594
23-3/8 584
23
D
in. mm
283
11-1/8
238
9-3/8
194
7-5/8
Unit Dimensions - inches (mm)
*NOTE - 20C/D size units that require second stage air volumes
over 1800 cfm (850 L/S) must have one of the following:
1. Single side return air with transition, to accommodate
20 x 25 x 1 in. (508 x 635 x 25 mm) air filter.
2. Single side return air with optional RAB Return Air Base
3. Bottom return air.
4. Return air from both sides.
5. Bottom and one side return air.
See Blower Performance Tables for additional information.
* Optional External Side Return Air Filter Kit is not for use with
the optional RAB Return Air Base.
FRONT VIEW SIDE VIEW

506550-01 Page 3 of 66Issue 1230
A96UHMV Exploded View
Figure 1

506550-01Page 4 of 66 Issue 1230
A96UHMV Gas Furnace
The A96UHMV Category IV gas furnace is equipped with a
variable capacity, varable speed integrated control. Each
A96UHMV is shipped ready for installation in the upflow,
horizontal left air discharge or horizontal right air discharge
position.
The furnace is equipped for installation in natural gas
applications only. Achange over kit must be ordered for LP/
propane applications.
The A96UHMV 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 A96UHMV 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/NFPA54). The National Fuel Gas Code
is available from the American National Standards
Institute, Inc., 11 West 42nd Street, New Your, 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 in Figures 10 and 11. Accessibility and service
clearances must take precedence over fire protection
clearances.
NOTE: For installation on combustible floors, the furnace
shall not be installed directly on carpeting, tile, or other
combustible material other than wood flooring.
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

506550-01 Page 5 of 66Issue 1230
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 A96UHMV 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 HEATor
COOL setting. See Figure 3.
The A96UHMV furnace may be installed in alcoves, closets,
attics, basements, garages, and utility rooms.
This furnace design has not been CSA Certified 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.
•Aroom 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/NFPANo. 70. The National Electric Code (ANSI/
NFPANo. 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 intermitent
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
Heating Unit Installed Upstream of Cooling Unit

506550-01Page 6 of 66 Issue 1230
•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
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 LLC
215 Metropolitan Drive
West Columbia, SC 29170
WARNING
These units should not be installed in areas normally
subject to freezing temperatures..
CAUTION
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 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
Do not install the furnace on its front or its back. See
Figure 4. 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
Upflow Applications
This gas furnace can be installed as shipped in the upflow
position. Refer to Figure 10 for clearances.
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 5.
Figure 4

506550-01 Page 7 of 66Issue 1230
SETTING EQUIPMENT
Figure 5
UNIT MUST BE LEVEL SIDE TO SIDE IN ALL APPLICATIONS FOR PROPER OPERATION.
ASLIGHT TILT TOWARD THE DRAIN IS RECOMMENDED FOR PROPER DRAINAGE.
TILT THE UNIT SLIGHTLY(MAX. 1/2”) FROM BACK TO FRONT TO AID IN THE DRAINING OF THE HEATEXCHANGER.

506550-01Page 8 of 66 Issue 1230
Removing the Bottom Panel
Remove the two screws that secure the bottom cap to the
furnace. Pivot the bottom cap down to release the bottom
panel. Once the bottom panel has been removed, reinstall
the bottom cap. See Figure 7.
Figure 7
Removing the Bottom Panel
Figure 6
Side Return Air
(with transition and filter)
A96UHMV applications which include side return air and a
condensate trap installed on the same side of the cabinet
(trap can be installed remotely within 5 feet) require either a
return air base or field fabricated transition to accommodate
an optional IAQ accessory taller than 14.5”. See Figure 6.
Optional Return Air Base
(Upflow Applications Only)
NOTE: Optional side return air filter kits are not for use with return air base.
1Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.
Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in. (584 x 279 mm).
The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.
Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return air opening.
The size of the opening must not extend beyond the markings on the furnace cabinet.
² To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.
FRONT VIEW SIDE VIEW
Figure 8

506550-01 Page 9 of 66Issue 1230
NOTE: Units with 1/2 hp blower motor are 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). See Figure 9. 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 9
Units with 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 10.
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.
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.
Return Air – Upflow Units
Return air can be brought in through the bottom or either
side of the furnace installed in an upflow application. If the
furnace is installed on a platform with bottom return, make
an airtight seal between the bottom of the furnace and the
platform to ensure that the furnace operates properly and
safely. The furnace is equipped with a removable bottom
panel to facilitate installation.
Markings are provided on both sides of the furnace cabinet
for installations that require side return air. Cut the furnace
cabinet at the maximum dimensions shown on page 2.
Installation Clearances
Figure 10
* Front 0
Back 0
Sides 0†
Vent
Floor
0
0‡
Top/Plenum 1 in. (25 mm)
* 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.
‡ For installations on a combustible floor, do not install the furnace
directly on carpeting, tile or other combustible materials other than
wood flooring.

506550-01Page 10 of 66 Issue 1230
Setting and Upflow Unit
When the side return air inlets are used in an upflow
application, it may be necessary to install shims on the
bottom of the furnace.
Horizontal Applications
The A96UHMV furnace can be installed in horizontal
applications with either right or left hand air discharge.
Refer to Figure 11 for clearances in horizontal applications.
Suspended Installation of Horizontal Unit
This furnace may be installed in either an attic or a
crawlspace. Either suspend the furnace from roof rafters or
floor joists, as shown in Figure 12 or install the furnace on a
platform, as shown in Figure 13. Ahorizontal suspension kit
(51W10) may be ordered or use equivalent.
NOTE: Heavy gauge sheet metal straps may be used to
suspend the unit from roof rafters or ceiling joists. When
straps are used to suspend the unit in this way, support must
be provided for both the ends. The straps must not interfere
with the plenum or exhaust piping installation. Cooling coils
and supply and return air plenums must be supported
separately.
NOTE: When the furnace is installed on a platform in a
crawlspace, it must be elevated enough to avoid water
damage and to allow the evaporator coil to drain.
Platform Installation of Horizontal Unit
1. Select location for unit keeping in mid service and other
necessary clearances. See Figure 11.
2. Construct a raised wooden frame and cover frame with
a plywood sheet. If unit is installed above finished space,
fabricate an auxiliary drain pan to be installed under unit.
Set unit in drain pan as shown in Figure 13. Leave 8
inches for service clearance below unit for condensate
trap, unless trap is installed remotely.
3. Provide a service platform in front of unit. When
installing the unit in a crawl space, a proper support
platform may be created using cement blocks.
4. Route auxiliary drain line so that water draining from
this outlet will be easily noticed by the homeowner.
5. If necessary, run the condensate line into a condensate
pump to meet drain line slope requirements. The pump
must be rated for use with condensing furnaces. Protect
the condensate discharge line from the pump to the
outside to avoid freezing.
6. Continue with exhaust, condensate and intake piping
installation according to instructions.
Typical Horizontal Application
Figure 12
Figure 11
Horizontal Application
Installation Clearances
Right-Hand Discharge
* Front 0
Back 0
Ends 0
Vent
Floor
0
0‡
Top 0
* Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
** An 8” service clearance must be maintained below the unit to
provide for servicing of the condensate trap. Unless the trap is
mounted remotely.
‡ For installations on a combustible floor, do not install the furnace
directly on carpeting, tile or other combustible materials other than
wood flooring.

506550-01 Page 11 of 66Issue 1230
Return Air - Horizontal Applications
Return air must be brought in through the end of a furnace
installed in the horizontal position. The furnace is equipped
with a removable bottom panel to facilitate installation. See
Figure 7.
Filters
This unit is not equipped with a filter or rack. Afield provided
filter is required for the unit to operate properly. Table 1 lists
recommended filter sizes.
A filter must be in place when the unit is operating!
NOTE: In upflow applications where side return air filter is
installed on same side as the condensate trap, make sure
that clearance is maintained to ensure future access to the
filter access panel.
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.
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 reflected light) of the heat exchanger for leaks after the
furnace is installed. If present, this access panel must always
be in place when the furnace is operating and it must not
allow leaks into or from the supply air duct system.
Return Air Plenum
Return air must not be drawn from a room where this furnace,
or any other gas fueled appliance (i.e., water heater), or
carbon monoxide producing device (i.e., wood fireplace) is
installed. 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.
Return air can be brought in through the bottom or either
side of the furnace. If a furnace with bottom return air is
installed on a platform, make an airtight seal between the
bottom of the furnace and the platform to ensure that the
unit operates properly and safely. Use fiberglass sealing
strips, caulking, or equivalent sealing method between the
plenum and the furnace cabinet to ensure a tight seal. If a
filter is installed, size the return air duct to fit the filter frame.
Figure 13
* Gas Connector may be used for Canadian installation if acceptable
by local authority having jurisdiction.
Table 1

506550-01Page 12 of 66 Issue 1230
Pipe and 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 2 for approved piping and fitting materials.
PIPING AND FITTINGS SPECIFICATIONS
Table 2
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 fittings
in the unit.
CAUTION
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
makeing 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.
Use PVC primer and solvent cement or ABS solvent cement
meeting ASTM specifications, refer to Table 2. As an
alternaate, 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 applicance must
be certified to ULCS636 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 3 lists the available exhaust termination kits, as well
as vent pipe equivalencies which must be used when sizing
vent pipe.

506550-01 Page 13 of 66Issue 1230
Joint Cementing Procedure
All cementing of joints should be done according to the
specifications outlined in ASTM D2855.
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 fitting socket and result in a
leaking joint.
3. Clean and dry surfaces to be joined.
4. Test fit joint and mark depth of fitting 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 fitting and male end of pipe to depth of fitting
socket.
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.
6. Promptly apply solvent cement to end of pipe and inside
socket surface of fitting. 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.
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 fitting socket. Aproperly made joint will show a bead
around its entire preimeter. Any gaps may indicate a
defective asembly due to insufficient solvent.
9. Handle joints carefully until completely set.
OUTDOOR TERMINATION KITS USAGE
Table 3

506550-01Page 14 of 66 Issue 1230
Venting Practices 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 from trap and lines.
Exhaust Piping (Figures 18 and 19)
3. Route piping to outside of structure. Continue with
installation following instructions given in piping
termination section.
The exhaust vent pipe operates under positive pressure
and must be completely sealed to prevent leakage of
combustion products into the living space.
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.
CAUTION
Vent Piping Guidelines
This unit is 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.
Intake and exhaust pipe sizing – Size pipe according to
Tables 4 and 5. Table 4 lists the minimum vent pipe lengths
permitted. Table 5 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. Refer to Table 6.
In some applications which permit the use of several different
sizes of vent pipe, a combination vent pipe may be used.
Contact Allied Air Technical Service for more information
concerning sizing of vent systems which include multiple
pipe sizes.
Use the steps in Figure 17 to correctly size vent pipe
diameter.
Figure 15
If this gas furnace replaces a 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 flue 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.
Piping Suspension Guidelines
NOTE: Isolate piping at the point where it exits the outside wall or
roof in order to prevent transmission of vibration to the structure.
Wall Thickness Guidelines
Figure 14

506550-01 Page 15 of 66Issue 1230
NOTE: The exhaust collar on all models is sized to
accommodate 2” Schedule 40 vent pipe. When vent pipe
which is larger than 2” must be used in an upflow application,
a 2” elbow must be applied at the exhaust collar in order to
properly transition to the larger diameter vent pipe. This
elbow must be added to the elbow count used to determine
acceptable vent lengths. Contact Allied Air Technical Service
for more information concerning sizing of vent systems which
include multiple pipe sizes.
Do not use screens or perforated metal in exhaust or
intake terminations. Doing so will cause freeze-ups and
may block the terminations.
IMPORTANT
EXHAUST PIPE
Figure 16
Horizontal Application
NOTE: All horizontal runs of exhaust pipe must slope back toward
unit. Aminimum of 1/4” (6 mm) drop for each 12” (305 mm) of
horizontal run is mandatory for drainage.
NOTE: Exhaust pipe MUST be glued to furnace exhaust fittings.
NOTE: Exhaust piping should be checked carefully to make sure
there are no sages or low spots.
* Any approved termination may be added to the minimum equivalent
length listed.
MINIMUM VENT PIPE LENGTHS
Table 4
Figure 17

506550-01Page 16 of 66 Issue 1230
Table 5
MAXIMUM ALLOWABLE VENT LENGTH (feet)

506550-01 Page 17 of 66Issue 1230
TYPICAL EXHAUST PIPE CONNECTIONS AND CONDENSATE TRAP INSTALLATION
IN UPFLOW APPLICATIONS
Figure 18
Figure 19
TYPICAL EXHAUST PIPE CONNECTIONS AND CONDENSATE TRAP INSTALLATION
IN HORIZONTAL AIR APPLICATIONS
(RIGHT HAND DISCHARGE SHOWN)

506550-01Page 18 of 66 Issue 1230
Intake Piping
This gas furnace may be installed only in direct vent
applications.
This gas furnace is designed for combustion air intake
through an inlet in the unit’s top cap. Intake air piping is
independent of exhaust piping.
TYPICAL AIR INTAKE PIPE CONNECTIONS IN HORIZONTAL DISCHARGE
AIR APPLICATIONS
(RIGHT HAND DISCHARGE SHOWN)
Figure 21
TYPICAL AIR INTAKE PIPE CONNECTIONS IN
UPFLOW APPLICATIONS
Figure 20

506550-01 Page 19 of 66Issue 1230
VENT TERMINATION CLEARANCES
FOR DIRECT VENT INSTALLATiONS IN THE USA AND CANADA
Figure 22

506550-01Page 20 of 66 Issue 1230
NOTE: Care must be taken to avoid recirculation of exhaust
back into intake pipe.
Details of Intake and Exhaust Piping Terminations for
Direct Vent Installations
NOTE: In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged to outdoors.
Intake and exhaust pipes may be routed either horizontally
through and outside wall or vertically through the roof. In
attic or closet installations, vertical termination through the
roof is preferred. Figures 23 through 29 show typical
terminations.
1. Exhaust and intake exits must be in same pressure zone.
Do not exit one through the roof and one on the side.
Also, do not exit the intake on one side and the exhaust
on another side of the house or structure.
2. Intake and exhaust pipes should be placed as close
together as possible at termination end (refer to
illustrations). Maximum separation is 3” (76 mm) on
roof terminations and 6” (152 mm) on sidewall
terminations.
3. On roof terminations, the intake piping should terminate
straight down using two 90° elbows (See Figure 23).
4. Exhaust piping must terminate straight out or up as
shown. Areducer is 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 6.
DIRECT VENT ROOF TERMINATION KIT
Figure 23
FIELD SUPPLIED WALL TERMINATION OR
See venting Table 5 for maximum venting lengths with this
arrangement.
* 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 6” (152 mm) from top of each pipe
(intake and exhaust).
Figure 24