Lennox G43UF−36C−090, G43UF−24B−045, G43UF−36C−090H, G43UF−48C−090, G43UF−48C−110 Installation Instructions Manual
...
Page 1
03/10
*2P0310*
506497−01
*P506497-01*
E 2010 Lennox Industries Inc.
Dallas, Texas, USA
UPFLOW
INSTALLATION
INSTRUCTIONS
G43UF
MERIT SERIES GAS FURNACE
UPFLOW AIR DISCHARGE
506497−01
03/2010
Supersedes 505,064M
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
This a safety alert symbol and should never be ignored.
When you see this symbol on labels or in manuals, be alert
to the potential for personal injury or death.
CAUTION
As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.
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.
Table of Contents
Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Identification 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping and Packing List 4. . . . . . . . . . . . . . . . . . . . . . .
Safety Information 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of Furnace as Constrction Heater 5. . . . . . . . . . . .
General 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Combustion, Dilution & Ventilation Air 6. . . . . . . . . . . . .
Installation − Setting Equipment 8. . . . . . . . . . . . . . . . . .
Filters 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Duct System 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pipe & Fittings Specifications 12. . . . . . . . . . . . . . . . . . .
Vent Piping Guidelines 14. . . . . . . . . . . . . . . . . . . . . . . . .
Joint Cementing Procedure 15. . . . . . . . . . . . . . . . . . . . .
Venting Practices 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Piping 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Start−Up 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Pressure Adjustment 35. . . . . . . . . . . . . . . . . . . . . .
High Altitude Information 36. . . . . . . . . . . . . . . . . . . . . . .
Testing for Venting and Combustion Air 37. . . . . . . . . .
Other Unit Adjustments 38. . . . . . . . . . . . . . . . . . . . . . . .
Blower Performance Data 39. . . . . . . . . . . . . . . . . . . . . .
Service 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Planned Service 43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition Control Board Diagnostic Codes 43. . . . . . . . .
Troubleshooting 44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair Parts List 47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vent Pipe Sizing Worksheet 48. . . . . . . . . . . . . . . . . . . .
Start−Up & Performance Check List 49. . . . . . . . . . . . . .
Litho U.S.A.
Page 2
Unit Dimensions − inches (mm)
*Bottom Return
Air Opening
*Bottom Return
Air Opening
ELECTRICAL INLET
(Either Side)
SUPPLY AIR
OPENING
AIR FLOW
FRONT VIEW SIDE VIEW
TOP VIEW
A
B 9/16 (14)
C
3/4 (19)
3/4 (19)
28−1/2
(724)
19−7/16
(494)
23−1/2
(597)
4−1/4
(108)
11−5/8 (295)
Right
9−3/4 (248)
Left
4−7/8 (124) Right
2−1/4 (57) Left
40
(1016)
4
(102)
1−15/16 (49)
23
(584)
14**
(356)
9/16
(14)
16
(406)
14−3/4
(375)
5/8 (16)
23-3/4 (603)
25 (635)
GAS PIPING INLET
(Either Side)
EXHAUST AIR OUTLET
(Either Side)
CONDENSATE
TRAP CONNECTION
(Either Side)
2−1/2
(64)
18-3/4 (476)
1
OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
1
OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
*OPTIONAL
RETURN CUTOUT
(Either Side)
1
Optional External Side Return Air Filter Kit is not for use
with the optional RAB Return Air Base.
*NOTE − 60C and 60D size units installed in upflow applications that require air volumes over 1800 cfm (850 L/s) must
have one of the following:
1. Single side return air with transition, to accommodate
20 x 25 x 1 in. (508 x 635 x 25 mm) air filter.
Required to maintain proper air velocity.
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.
Refer to Engineering Handbook for additional information.
**Consider sizing requirements for optional IAQ equipment
before cutting side return opening.
COMBUSTION AIR INTAKE
(Either Side)
6−1/2
(165)
4−1/8
(103)
6−3/4
(171)
3−1/8
(79)
Model No.
A B C
in. mm in. mm in. mm
G43UF−24B−045
G43UF−24B−070
G43UF−36B−070
17−1/2 446 16−3/8 416 16 406
G43UF−36C−090
G43UF−36C−090H
G43UF−48C−090
G43UF−48C−110
G43UF−48C−110H
G43UF−60C−110
21 533 19−7/8 504 19−1/2 495
G43UF−60D−135 24−1/2 622 23−3/8 546 23 584
Page 3
Parts Arrangement
G43UF PARTS IDENTIFICATION
FIGURE 1
TOP CAP
CABINET
BURNER BOX
ASSEMBLY
SIGHT
GLASS
DuralokPlus
TM
HEAT EXCHANGER
ASSEMBLY
CONDENSER COIL
CONTROL BOX
DOOR
INTERLOCK
SWITCH
COLD HEADER
(COLLECTOR)
BOX
COMBUSTION AIR
INDUCER
BLOWER
ACCESS
DOOR
BURNER
ACCESS
PANEL
FLUE
COLLAR
COMBUSTION
AIR PRESSURE
PROVE SWITCH
PRIMARY LIMIT
WARM HEADER
(COLLECTOR)
BOX
GAS VALVE
AND MANIFOLD
BLOWER
ASSEMBLY
Page 4
G43UF Gas Furnace
The G43UF Category IV gas furnace is shipped ready for
installation in the upflow position. The furnace is shipped
with the bottom panel in place. The bottom panel must be
removed if the unit is to be installed in upflow applications
with bottom return air.
The G43UF can be installed as either a Direct Vent or a
Non−Direct Vent gas central furnace.
The furnace is equipped for installation in natural gas applications. A conversion kit (ordered separately) is required for use in propane/LP gas applications.
NOTE − In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors. In
Non−Direct Vent installations, combustion air is taken from
indoors and flue gases are discharged outdoors. See figure
2 for applications involving roof termination.
FIGURE 2
DIRECT VENT INSTALLATION NON−DIRECT VENT
INSTALLATION
EXHAUST
OUTLET
COMBUSTION
AIR INTAKE
OUTSIDE OF
HOUSE
CONDENSATE
DRAIN
EXHAUST
OUTLET
G43UF
COMBUSTION
AIR INTAKE INSIDE
OF HOUSE
G43UF
CONDENSATE
DRAIN
Shipping and Packing List
Package 1 of 1 contains
1 − Assembled G43UF unit
1 − Bag assembly containing the following:
3 − Screws
3 − Wire nuts
1 − Snap bushing
1 − Snap plug
1 − Wire tie
1 − Condensate trap
1 − Condensate trap cap
2 − 2" diameter vent / intake plugs
1 − 3" diameter cabinet plug (intake)
1 − 2" diameter debris screen
NOTE − G43UF−48C−110, G43UF−110H and G43UF−60C−110
units also include a 2" diameter PVC street elbow, which is
shipped on the blower deck in the heating compartment.
G43UF−60D−135 units are shipped with a 3" to 2" PVC reducing elbow.
Canadian Installations Only − Replace the provided 2"
street elbow shipped with the G43UF−110, G43UF−110H and
G43UF−60C−110 units with 2" street elbow Y0162. Replace
the provided 3" X 2" reducing elbow shipped with the
G43UF−60D−135 units with 3" X 2" reducing elbow 40W22.
Y0162 and 40W22 meet B149 vent requirements.
DANGER
Danger of explosion.
There are circumstances in which odorant used with
LP/propane gas can lose its scent. In case of a leak,
LP/propane gas will settle close to the floor and may
be difficult to smell. An LP/propane leak detector
should be installed in all LP applications.
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
The following items may also be ordered separately:
1 − Thermostat
1 − Propane/LP changeover kit
Safety Information
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.
Use only the type of gas approved for use with this furnace.
Refer to unit nameplate.
G43UF units are CSA International certified to ANSI
Z21.47 and CSA 2.3 standards.
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 following address:
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.
Page 5
In order to ensure proper unit operation in non−direct vent
applications, combustion and ventilation air supply must be
provided according to the current National Fuel Gas Code
or CSA-B149 standard.
This furnace is CSA International certified for installation
clearances to combustible material as listed on the unit
nameplate and in the table in figure 8. 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.
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 within the range specified on the unit nameplate. Failure
to do so may cause erratic limit operation and premature heat
exchanger failure.
This G43UF furnace must be installed so that its electrical
components are protected from water.
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.
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
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 intermit-
tent 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.
The G43UF furnace may be installed in alcoves, closets,
attics, basements, garages, and utility rooms in the upflow
position.
This furnace design has not been CSA certified for installation in mobile homes, recreational vehicles, or outdoors.
Never use an open flame to test for gas leaks. Check all
connections using a commercially available soap solution
made specifically for leak detection.
Use of Furnace as Construction Heater
Lennox does not recommend the use of G43UF units as a
construction heater during any phase of construction. Very
low return air temperatures, harmful vapors and operation
of the unit with clogged or misplaced filters will damage the
unit.
G43UF units may be used for heating of buildings or structures under construction, if the following conditions are
met:
D The vent system must be permanently installed per
these installation instructions.
D A room thermostat must control the furnace. The use of
fixed jumpers that will provide continuous heating is not
allowed.
D The return air duct must be provided and sealed to the
furnace.
D Return air temperature range between 60°F (16°C) and
80°F (27°C) must be maintained.
D Air filters must be installed in the system and must be
maintained during construction.
D Air filters must be replaced upon construction comple-
tion.
D The input rate and temperature rise must be set per the
furnace rating plate.
D One hundred percent (100%) outdoor air must be pro-
vided for combustion air requirements during construction. Temporary ducting may supply outdoor air to the
furnace. Do not connect duct directly to the furnace.
Size the temporary duct following these instructions in
section for Combustion, Dilution and Ventilation Air in a
confined space with air from outside.
D The furnace heat exchanger, components, duct system,
air filters and evaporator coils must be thoroughly
cleaned following final construction clean−up.
D All furnace operating conditions (including ignition, in-
put rate, temperature rise and venting) must be verified
according to these installation instructions.
Page 6
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 a G43UF furnace:
• 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 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 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 condensate drain system.
CAUTION
G43UF unit should not be installed in areas normally
subject to freezing temperatures.
WARNING
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.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379−9900
Combustion, Dilution & Ventilation Air
If the G43UF 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 flue gases are discharged out−
doors.
WARNING
Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rusting and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result
in safety and performance related problems. Avoid
exposure to the following substances in the combustion air supply:
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine base swimming pool chemicals
Water softening chemicals
De−icing salts or chemicals
Carbon tetrachloride
Halogen type refrigerants
Cleaning solvents (such as perchloroethylene)
Printing inks, paint removers, varnishes, etc.
Hydrochloric acid
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials
In the past, there was no problem in bringing in sufficient
outdoor air for combustion. Infiltration provided all the air
that was needed. In today’s homes, tight construction
practices make it necessary to bring in air from outside
for combustion. Take into account that exhaust fans, appliance vents, chimneys, and fireplaces force additional
air that could be used for combustion out of the house.
Unless outside air is brought into the house for combustion, negative pressure (outside pressure is greater than
inside pressure) will build to the point that a downdraft
can occur in the furnace vent pipe or chimney. As a result,
combustion gases enter the living space creating a potentially dangerous situation.
In the absence of local codes concerning air for combus−
tion and ventilation, use the guidelines and procedures in
this section to install G43UF furnaces to ensure efficient
and safe operation. You must consider combustion air
needs and requirements for exhaust vents and gas pip−
ing. A portion of this information has been reprinted with
permission from the National Fuel Gas Code (ANSI−
Z223.1/NFPA 54). This reprinted material is not the complete and official position of the ANSI on the referenced
subject, which is represented only by the standard in its
entirety.
In Canada, refer to the CSA B149 installation codes.
CAUTION
Do not install the furnace in a corrosive or contaminated atmosphere. Meet all combustion and ventilation air requirements, as well as all local codes.
Page 7
All gas-fired appliances require air for the combustion process. If sufficient combustion air is not available, the furnace or other appliance will operate inefficiently and unsafely. Enough air must be provided to meet the needs of all
fuel−burning appliances and appliances such as exhaust
fans which force air out of the house. When fireplaces, exhaust fans, or clothes dryers are used at the same time as
the furnace, much more air is required to ensure proper
combustion and to prevent a downdraft. Insufficient 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 unconfined or a confined space.
Unconfined Space
An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
feet (1.42 m
3
) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space.
This space also includes adjacent rooms which are not
separated by a door. Though an area may appear to be unconfined, it might be necessary to bring in outdoor air for
combustion if the structure does not provide enough air by
infiltration. If the furnace is located in a building of tight
construction with weather stripping and caulking around
the windows and doors, follow the procedures in the air
from outside section.
Confined Space
A confined space is an area with a volume less than 50 cubic
feet (1.42 m
3
) per 1,000 Btu (.29 kW) per hour of the com−
bined input rating of all appliances installed in that space. This
definition includes furnace closets or small equipment rooms.
When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space containing the furnace, the return air must be handled by ducts
which are sealed to the furnace casing and which terminate
outside the space containing the furnace. This is especially
important when the furnace is mounted on a platform in a
confined space such as a closet or small equipment room.
Even a small leak around the base of the unit at the platform
or at the return air duct connection can cause a potentially
dangerous negative pressure condition. Air for combustion
and ventilation can be brought into the confined space either from inside the building or from outside.
Air from Inside
If the confined space that houses the furnace adjoins a
space categorized as unconfined, air can be brought in by
providing two permanent openings between the two
spaces. Each opening must have a minimum free area of 1
square inch (645 mm
2
) per 1,000 Btu (.29 kW) per hour of
total input rating of all gas−fired equipment in the confined
space. Each opening must be at least 100 square inches
(64516 mm
2
). One opening shall be within 12 inches (305
mm) of the top of the enclosure and one opening within 12
inches (305 mm) of the bottom. See figure 3.
FIGURE 3
EQUIPMENT IN CONFINED SPACE − ALL AIR FROM INSIDE
OPENINGS
(To Adjacent
Unconfined
Space)
NOTE − Each opening shall have a free area of at least one square
inch per 1,000 Btu (645mm
2
per .29kW) per hour of the total input
rating of all equipment in the enclosure, but not less than 100 square
inches (64516mm.
2).
ROOF TERMINATED
EXHAUST PIPE
SIDE WALL
TERMINATED EX-
HAUST PIPE (ALTER-
NATE LOCATION)
G43UF
Air from Outside
If air from outside is brought in for combustion and ventilation, the confined space shall be provided with two permanent openings. One opening shall be within 12" (305mm)
of the top of the enclosure and one within 12" (305mm) 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 (645mm
2
per 1.17kW) per hour of total input rating of all equipment
in the enclosure. When communicating with the outdoors
through horizontal ducts, each opening shall have a minimum free area of 1 square inch per 2,000 Btu (645mm
2
per .59kW) per total input rating of all equipment in the enclosure (See figure 4).
Page 8
FIGURE 4
EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE
(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)
NOTE−The inlet and outlet air openings shall each have a free area
of at least one square inch per 4,000 Btu (645mm
2
per 1.17kW) per
hour of the total input rating of all equipment in the enclosure.
OUTLET
AIR
INLET
AIR
VENTILATION
LOUVERS
(For unheated
crawl space)
G43UF
ROOF TERMINATED
EXHAUST PIPE
VENTILATION LOUVERS
(Each end of attic)
SIDE WALL
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
If air from outside is brought in for combustion and ventilation, the confined space must have two permanent openings. One opening shall be within 12 inches (305 mm) of
the top of the enclosure and one opening within 12 inches
(305 mm) of the bottom. These openings must communicate directly or by ducts with the outdoors or spaces (crawl
or attic) that freely communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a
minimum free area of 1 square inch (645 mm
2
) per 4,000
Btu (1.17 kW) per hour of total input rating of all equipment
in the enclosure. See figures 4 and 5. When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch (645
mm
2
) per 2,000 Btu (.56 kW) per total input rating of all
equipment in the enclosure. See figure 6.
When ducts are used, they shall be of the same cross−sec-
tional area as the free area of the openings to which they
connect. The minimum dimension of rectangular air ducts
shall be no less than 3 inches (75 mm). In calculating free
area, the blocking effect of louvers, grilles, or screens
must be considered. If the design and free area of protective covering is not known for calculating the size opening
required, it may be assumed that wood louvers will have
20 to 25 percent free area and metal louvers and grilles
will have 60 to 75 percent free area. Louvers and grilles
must be fixed in the open position or interlocked with the
equipment so that they are opened automatically during
equipment operation.
FIGURE 5
EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE
(All Air Through Ventilated Attic)
NOTE−The inlet and outlet air openings shall each have a free area of
at least one square inch per 4,000 Btu (645mm
2
per 1.17kW) per hour
of the total input rating of all equipment in the enclosure.
OUTLET
AIR
VENTILATION LOUVERS
(Each end of attic)
INLET AIR
(Ends 12" above
bottom)
ROOF TERMINATED
EXHAUST PIPE
SIDE WALL
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
G43UF
FIGURE 6
EQUIPMENT IN CONFINED SPACE −
ALL AIR FROM OUTSIDE
OUTLET AIR
INLET AIR
NOTE−Each air duct opening shall have a free area of at least one
square inch per 2,000 Btu (645mm
2
per .59kW) per hour of the total
input rating of all equipment in the enclosure. If the equipment room
is located against an outside wall and the air openings communicate directly with the outdoors, each opening shall have a free area
of at least 1 square inch per 4,000 Btu (645mm
2
per 1.17kW) per
hour of the total input rating of all other equipment in the enclosure.
ROOF TERMINATED
EXHAUST PIPE
SIDE WALL
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
G43UF
Installation − Setting Equipment
WARNING
Do not install the furnace on its front or its back. Do
not connect the return air ducts to the back of the furnace. Doing so will adversely affect the operation of
the safety control devices, which could result in personal injury or death.
Page 9
The G43UF gas furnace can be installed as shipped in
the upflow position only. Refer to figure 8 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 front to back and side
to side. The unit may be tilted slightly (maximum 1/2 in.)
from back to front to aid in the draining of the heat exchanger. See figure 7.
FIGURE 7
FRONT VIEW SIDE VIEW
AIR FLOW
AIR FLOW
UNIT
FRONT
1/2"
max.
UNIT SHOULD BE LEVEL FROM LEFT TO RIGHT BUT MAY BE
TILTED SLIGHTLY (MAX. 1/2") FROM BACK TO FRONT
TO AID IN THE DRAINING OF THE HEAT EXCHANGER.
NOTE − 1/3 hp blower motors are equipped with four flexible mounting legs, and 1/2 hp blower motors 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). The bolt and washer must be re-
moved before the furnace is placed into operation. After the bolt and washer have been removed, the rigid leg
will not touch the blower housing.
NOTE − G43UF−60D−135 units are equipped with a shipping pad under the blower housing. Remove the shipping
pad prior to operation.
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or alcove installations are shown in figure 8.
WARNING
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.
Installation Clearances
Top
Bottom (Floor)
Left Side
Right Side
Top/Plenum 1 in. (25 mm)
*Front 0
Back 0
Sides 0†
Vent 0
Floor 0‡
*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.
FIGURE 8
Return Air Guidelines
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.
Page 10
Markings are provided on both sides of the furnace cabinet
for installations that require side return air. Cut the furnace
cabinet at the maximum dimensions shown on page 2.
NOTE − When air volumes over 1800 cfm (850 L/s) are
required with 60C or 60D models in an upflow application, the following return air options are available:
1 − Return air from single side with transition which will
accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm) air filter.
(Required to maintain proper air velocity.) See figure 9.
2 − Return air from single side with optional RAB Return
Air Base. See figure 10.
3 − Return air from bottom.
4 − Return air from both sides.
5 − Return air from bottom and
one side.
Refer to Engineering Handbook for additional information.
G43UF applications which include side return air and a
condensate trap installed on the same side of the cabinet require either a return air base or field−fabricated
transition to accommodate an optional IAQ accessory
taller than 14−1/2".
Side Return Air
(with transition and filter)
FIGURE 9
Return Air
Plenum
Transition
20" X 25" X 1"
(508mm X635mm X 25mm)
Air Filter
FIGURE 10
Optional Return Air Base
NOTE− Optional Side Return Air Filter Kits are not for use with RAB Return Air Base.
1
Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.
Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in.
(584 x 279 mm).
The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.
Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return
air opening. The size of the opening must not extend beyond the markings on the furnace cabinet.
2
To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.
NOTE− Optional Side Return Air Filter Kits are not for use with RAB Return Air Base.
1
Unit side return air
Opening
FRONT VIEW
SIDE VIEW
27−5/8 (702)
4
(102)
1
23 (584)
Overall
(Maximum)
OPTIONAL RAB
RETURN AIR BASE
23 (584)
7−1/4 (184)
7/8
(22)
3/4
(19)
1
22−7−16
(570)
Overall
(Maximum)
SIDE RETURN
AIR OPENINGS
(Either Side)
FURNACE
FRONT
14
(356)
AIR FLOW
5−5/8
(143)
1
Minimum
11 (279)
2
Maximum
14 (356)
21 (533) RAB−C (98M58)
24−1/2 (622) RAB−D (98M59)
17−1/2 (446) RAB−B (98M60)
Page 11
Removing the Bottom Panel
FIGURE 11
Screw
Bottom Panel
Bottom Cap
Removing the Bottom Panel
Remove the two screws that secure the bottom cap to the
furnace. Pivot the bottom cap down to release the bottom
panel. Once the bottom panel has been removed, reinstall
the bottom cap. See figure 11.
FIGURE 12
1−3/4
(44)
1−3/4
(44)
3/8
(10)
1−3/4 (44)
3/8
(10)
3/8
(10)
3/8
(10)
1−3/4
(44)
Leveling Bolt Installation
Leveling Bolt
Locations
Leveling Bolt
Locations
Inches (mm)
Furnace Front
Furnace
Bottom
Leveling an Upflow Unit
When the side return air inlets are used in an upflow application, it may be necessary to install leveling bolts on the
bottom of the furnace. Use field−supplied corrosion−resistant 5/16 inch machine bolts (4) and nuts (8). See figure 12.
NOTE − The maximum length of the bolt is 1−1/2 inches.
1 − Lay the furnace on its back and drill a 5/16 inch diame-
ter hole in each corner of the furnace’s bottom. See figure 12 for the correct location of the holes. Drill through
the bottom panel and the bottom flange of the cabinet.
2 − Install one bolt and two nuts into each hole. Screw the
first nut onto a bolt and then insert the bolt into a hole. A
flat washer may be added between the nut and the bottom of the unit.
3 − Screw another nut onto the bolt on the inside of the fur-
nace base. A flat washer may be added between the
nut and the bottom of the unit.
4 − Adjust the outside nut to the appropriate height and
tighten the inside nut to secure the arrangement.
NOTE − The unit may be tilted back−to−front a maximum of
1/2". This will ensure proper draining of the heat exchanger.
Filters
This unit is not equipped with a filter or rack. A field−provided filter is required for the unit to operate properly. Table
1 lists recommended filter sizes.
A filter must be in place whenever the unit is operating.
TABLE 1
Furnace
Cabinet Width
Filter Size
Side Return Bottom Return
17−1/2" 16 X 25 X 1 (1) 16 X 25 X 1 (1)
21" 16 X 25 X 1 (1) 20 X 25 X 1 (1)
24−1/2" 16 X 25 X 1 (2) 24 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 − Operation of this furnace in heating mode (indoor
blower operating at selected heating speed) with an external static pressure which exceeds 0.5 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. 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.
Page 12
Return Air Plenum
NOTE − Return air must not be drawn from a room
where this furnace, or any other gas−fueled appliance (i.e., water heater), or carbon monoxide−
producing device (i.e., wood fireplace) is installed.
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.
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 the table 2 below for approved piping and fitting materials.
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 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.
TABLE 2
PIPING AND FITTINGS SPECIFICATIONS
PIPE & FITTING MATERIAL
ASTM
SPECIFICATION
Schedule 40 PVC (Pipe) D1785
Schedule 40 PVC (Cellular Core Pipe) F891
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 Cellular Core DWV (Pipe) F628
Schedule 40 ABS (Pipe) D1527
Schedule 40 ABS (Fittings) D2468
ABS−DWV (Drain Waste & Vent)
(Pipe & Fittings)
D2661
PVC−DWV (Drain Waste & Vent)
Pipe & Fittings)
D2665
PRIMER & SOLVENT CEMENT
ASTM
SPECIFICATION
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
D2564, D2235,
F493
ABS to PVC or CPVC Transition Solvent
Cement
D3138
CANADA PIPE & FITTING & SOLVENT
CEMENT
MARKING
PVC & CPVC Pipe and Fittings
ULCS636
PVC & CPVC Solvent Cement
ABS to PVC or CPVC Transition Cement
Use PVC primer and solvent cement or ABS solvent cement
meeting ASTM specifications, refer to Table 2. 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 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.
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. When bonding the vent system to the furnace, use ULC S636 approved One−Step Transition Cement to bond the pipe to the flue collar, or to bond the 90°
elbow or reducing 90° elbow to the flue collar. 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. All Lennox vent terminations are PVC.
Page 13
TABLE 3
OUTDOOR TERMINATION KITS AND CORRESPONDING EQUIVALENCIES
UNIT
MODEL
VENT
PIPE
DIA.
(in.)
Vent Pipe Length Equivalency (feet)
Outdoor
Exhaust
Accelerator
(Dia. X
Length)
Outdoor
Exhaust
Accelerator
(Dia. X
Length)
1−1/2" Con-
centric Kit
2"
Concentric
Kit
3"
Concentric
Kit
2" Wall Plate
Kit
3" Wall
Plate Kit
2" Wall
Ring Kit
1−1/2" X 12"
2" X 12"
71M80
or
44W92
69M29
or
44W92
60L46
or
44W93
22G44
or 30G28
44J40
or 81J20
15F74
24B−045
2 4
Not
Allowed
12
Not
Allowed
Not
Allowed
4 4* 4
2−1/2 5
Not
Allowed
15
Not
Allowed
Not
Allowed
5 5* 5
3 7
Not
Allowed
21
Not
Allowed
Not
Allowed
7 7* 7
4 14
Not
Allowed
42
Not
Allowed
Not
Allowed
14 14* 14
24B−070
36B−070
2 4
Not
Allowed
12
Not
Allowed
Not
Allowed
4 4* 4
2−1/2 5
Not
Allowed
15
Not
Allowed
Not
Allowed
5 5* 5
3 8
Not
Allowed
24
Not
Allowed
Not
Allowed
8 8* 8
4 14
Not
Allowed
42
Not
Allowed
Not
Allowed
14 14* 14
36C−090
36C−090H
48C−090
2
Not
Allowed
1
Not
Allowed
3 3
Not
Allowed
1 1**
2−1/2
Not
Allowed
2
Not
Allowed
6 6
Not
Allowed
2 2**
3
Not
Allowed
2
Not
Allowed
6 6
Not
Allowed
2 2**
4
Not
Allowed
4
Not
Allowed
12 12
Not
Allowed
4 4**
48C−110
48C−110H
60C−110
2
Not
Allowed
1
Not
Allowed
3 3
Not
Allowed
1 1**
2−1/2
Not
Allowed
2
Not
Allowed
6 6
Not
Allowed
2 2***
3
Not
Allowed
2
Not
Allowed
6 6
Not
Allowed
2 2***
4
Not
Allowed
4
Not
Allowed
12 12
Not
Allowed
4 4***
60D−135
3
Not
Allowed
6
Not
Allowed
Not
Allowed
15
Not
Allowed
6 6***
4
Not
Allowed
10
Not
Allowed
Not
Allowed
25
Not
Allowed
10 10***
*Requires field−provided and installed 1−1/2" exhaust accelerator.
**Requires field−provided and installed 2" exhaust accelerator.
***For use only in non−direct vent applications, when snow riser is
not required. Requires field−provided and installed 2" exhaust accelerator.
Termination kits 44W92, 44W93, 30G28 & 81J20 are ULC−636
approved for Canadian Installation.
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 G43UF−24B−045, G43UF−24B−070 and G43UF−36B−070
furnaces.
Page 14
Vent Piping Guidelines
The G43UF 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 flue gases are discharged outdoors.
In Direct Vent installations, combustion air is taken from outdoors and flue gases are discharged outdoors.
Intake and exhaust pipe sizing in Direct Vent applications
and exhaust pipe sizing in Non-Direct Vent applications −−
Size pipe according to tables 4 and 5. Table 4 lists the minimum equivalent vent pipe lengths permitted. Table 5 lists
the maximum equivalent pipe lengths permitted.
Maximum vent length is defined as:
Total length (linear feet) of pipe,
Plus Equivalent length (feet) of fittings,
Plus Equivalent length (feet) of termination.
NOTE − Include ALL pipe and ALL fittings, both
indoors and outdoors.
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.
NOTE − The exhaust pipe should be offset a minimum of 12
inches to avoid the possibility of water droplets being released from the exhaust termination. The minimum exhaust vent length is 15 ft. Shorter exhaust vent lengths may
result in the discharge of water droplets from the exhaust
termination, in spite of the 12−inch vertical offset.
Each 90° elbow (including those provided with the furnace)
of any diameter is equivalent to 5 feet (1.52m) of vent pipe
of the same diameter. Two 45° elbows are equivalent to
one 90° elbow of the same diameter. One 45° elbow is
equal to 2.5 feet (.76m) of vent pipe of the same diameter.
In some applications which permit the use of several different sizes of vent pipe, a combination vent pipe may be
used. Contact the Application Department for assistance in
sizing vent pipe in these applications.
NOTE − The flue collar on all models is sized to accommodate 2" Schedule 40 flue pipe. When vent pipe which is
larger than 2" must be used in an upflow application, a 2"
elbow must be applied at the flue collar in order to properly transition to the larger diameter flue pipe. This elbow
must be added to the elbow count used to determine acceptable vent lengths. Assign an equivalent feet value to
this elbow according to the larger size pipe being used.
Contact the Application Department for more information
concerning sizing of vent systems which include multiple
pipe sizes.
Use the following steps to correctly size vent pipe diameter.
Refer to Vent Pipe Size Determination Worksheet on
Page 48.
1 − Determine the vent termination and its corresponding
equivalent feet value according to table 3.
2 − Determine the number of 90° elbows required for both
indoor and outdoor (e.g. snow riser) use. Calculate the
corresponding equivalent feet of vent pipe.
3 − Determine the number of 45° elbows required for both
indoor and outdoor use. Calculate the corresponding
equivalent feet of vent pipe.
4 − Determine the length of straight pipe required.
5 − Add the total equivalent feet calculated in steps 1
through 4 and compare that length to the maximum
values given in table 5 for the proposed vent pipe di-
ameter. If the total equivalent length required exceeds
the maximum equivalent length listed in the appropri-
ate table, evaluate the next larger size pipe.
IMPORTANT
Do not use screens or perforated metal in exhaust
terminations. Doing so will cause freeze−ups and
may block the terminations.
TABLE 4
MINIMUM VENT PIPE LENGTHS
G43UF
MODEL
MIN. EQUIV.
VENT LENGTH
EXAMPLE
045, 070,
090
15 ft.*
5 ft. plus 2 elbows of 2", 2−1/2", 3"
or 4" diameter pipe
110**
5 ft. plus 2 elbows of 2", 2−1/2", 3" or
4" diameter pipe
135***
5 ft. plus 2 elbows of 3" or 4"
diameter pipe
*Any approved termination may be added to the minimum equivalent length
listed.
**G43UF−48C−110, G43UF−110H and G43UF−60C−110 must have 90° street
ell (supplied or field replacement Canadian kit) installed directly into unit flue
collar.
***G43UF−60D−135 must have 3" to 2" reducing ell (supplied or field replacement Canadian kit) installed directly into unit flue collar.
TABLE 5
MAXIMUM VENT PIPE LENGTHS
DIRECT (2 PIPE) AND NON−DIRECT (1 PIPE) APPLICATIONS
ALTITUDE
G43UF
MODEL
MAXIMUM EQUIVALENT VENT
LENGTH FEET
2" dia. 2−1/2" dia. 3" dia. 4" dia.
0 − 2000
(0 − 609 m)
045 110 135 160 250
070 70 135 160 250
090 50 100 125 225
110* 30 70 125 200
135** n/a n/a ***125 180
2001 − 4500
(610 − 1371 m)
045 110 135 160 250
070 70 135 160 250
090 50 100 125 225
110* 20 70 125 200
135** n/a n/a ***90 180
4501−7500
(1372−2286 m)
045 110 135 160 250
070 70 135 160 250
090 30 100 125 225
110* n/a 70 125 200
135** n/a n/a ***90 180
7501 − 10000
(2287 − 3048 m)
045 110 135 160 250
070 70 135 160 250
090 n/a 100 125 225
110* n/a 70 125 200
135** n/a n/a ***90 180
n/a −− Not allowed.
*G43UF−48C−110 and G43UF−60C−110 must have 90° street ell (supplied)
installed directly into unit flue collar.
**G43UF−60D−135 must have 3" to 2" reducing ell (supplied) installed directly
into unit flue collar.
***90° elbows used in configuration of G43UF−60D−135 vent, must be limited to 3" sweep elbows.
Page 15
Joint Cementing Procedure
All cementing of joints should be done according to the
specifications outlined in ASTM D 2855.
WARNING
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 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.
NOTE − Furnace flue collar and air inlet fitting are both
made of ABS material. Use transition solvent cement
when joining ABS fittings to PVC pipe.
6 − Promptly apply solvent cement to end of pipe and in-
side 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. A properly made joint will show a
bead around its entire perimeter. Any gaps may indicate a defective assembly due to insufficient solvent.
9 − Handle joints carefully until completely set.
Venting Practices
The thickness of construction through which vent pipes
may be installed is 24" (610mm) maximum and 3/4"
(19mm) minimum.
1 − Use recommended piping materials for exhaust pip-
ing.
2 − Secure all joints, including drip leg, gas-tight using ap-
proved cement.
Suspend piping using hangers at a minimum of every 5
feet (1.52m) for schedule
40 PVC and every 3 feet
(.91m) for ABS−DWV, PVC−
DWV, SPR−21 PVC, and
SDR−26 PVC piping. A suitable hanger can be fabricated by using metal or
plastic strapping or a large
wire tie.
3 − In areas where piping penetrates joists or interior
walls, hole must be large enough to allow clearance on
all sides of pipe through center of hole using a hanger.
4 − Secure piping at the point where it exits the outside
wall or roof in order to prevent transmission of vibration to the structure.
5 − 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
NOTE − A 2" diameter PVC street ell is located on the
blower deck of 48C−110, 48C−110H and 60C−110 units
(or use field replacement Canadian Kit). In upflow ap-
plications, the street ell must be
glued using transition
solvent cement directly into the unit flue collar (or use
field replacement Canadian Kit). See figure 14. A 3" to 2"
PVC reducing ell is located on the blower deck of the
60D−135 units. In upflow applications, the reducing ell
must be
glued using transition solvent cement directly
into the unit flue collar.
1 − Choose the appropriate side for venting. Glue the
field−provided exhaust vent pipe (or provided street
ell) to the flue collar. All cement joints should be made
according to the specifications outlined in ASTM D
2855. Refer to pipe and fittings specifications and gluing procedures.
IMPORTANT
Exhaust piping and condensate trap must be
installed on the same side of the unit in upflow and
dowflow applications or use alternate drain kit
76M20.
FIGURE 13
STRAPPING
(metal, plastic
or large wire
ties)
Page 16
FIGURE 14
TYPICAL EXHAUST PIPE CONNECTIONS AND CONDENSATE TRAP INSTALLATION
IN UPFLOW DIRECT OR NON−DIRECT VENT APPLICATIONS
(Right−Hand Exit)
VENT PLUG
(Must be
glued in
place)
PLUG
*2" diameter street elbow provided.
CONDENSATE
TRAP
(Must be installed
on same side as
exhaust piping)
−135 with
3" OR 4" vent pipe
3" to 2" REDUCING ELBOW
(provided)
2"
−045, −070, or
−090 with
2−1/2", 3", or 4"
vent pipe
2"
TRANSITION
(use only if 4"
pipe is
required)
4"
2"
2"
2−1/2",
3", OR
4"
TRANSITION
2"
2"
−110 with
2−1/2", 3", OR 4"
vent pipe
*2"
TRANSITION
2−1/2",
3", OR
4"
2"
**2
45°
MAX
45°
MAX
SIDE VIEW
or
** Street elbow may be used on −045, −070 and −090.
−045, −070 or
−090 ONLY
−110 with 2"
vent pipe
2 − All horizontal runs of exhaust pipe must slope back to-
ward unit. A minimum of 1/4" (6mm) drop for each 12"
(305mm) of horizontal run is mandatory for drainage.
Horizontal runs of exhaust piping must be supported every 5 feet (1.52m) using hangers.
NOTE − Exhaust piping should be checked carefully to
make sure there are no sags or low spots.
3 − On the opposite side of the cabinet, glue the provided
2" ABS vent plug into the unused ABS flue collar with
ABS or all purpose solvent cement.
4 − 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.
CAUTION
The exhaust vent pipe operates under positive pressure and must be completely sealed to prevent leakage of combustion products into the living space.
FIGURE 15
Exhaust Pipe Offset
12" Min.*
12" Min.
Upflow Application
Rooftop Termination
Upflow Application
Side Wall Termination
*A minimum of 1/4" (6mm) drop for each 12" (305mm) of horizontal run is
mandatory for drainage
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