507714-01
Page 13 of 52
Issue 1716
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.
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.
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
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 fitting
in the unit.
IMPORTANT
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.
Table 5. Outdoor Termination Kits Usage
Capacity
VENT
PIPE DIA.
(in.)
STANDARD
CONCENTRIC
Outdoor Exhaust
Accelerator
(Dia. X Length)
Outdoor
Exhaust
Accelerator
(Dia. X Length)
Flush
Mount Kit
1-1/2”
Concentric
Kit
2”
Concentric
Kit
3”
Concentric
Kit
1-1/2” X 12”
2” X 12”
51W11 **
71M80
or
+44W92++
69M29
or
+44W92++
60L46
or 44W93+
045
2
YES
YES
YES
2-1/2
YES
YES
YES
3
YES
YES
YES
070
2
YES
YES
YES
2-1/2
YES
YES
YES
3
YES
YES
YES
090
2
YES
YES
YES
YES
2-1/2
YES
YES
YES
YES
3
YES
YES
YES
YES
110
2
YES
YES
YES
YES
2-1/2
YES
YES
YES
YES
3
YES
YES
YES
YES
* Requires field-provided and installed 1-1/2” exhaust accelerator.
** Kit 51W11 is provided with a 1-1/2” accelerator which must be for all 2 and 2-1/2” PVC installations.
+ Termination kits 44W92 and 44W93 are approved for use in Canadian installations to meet CSAB149.
++ The 44W92 Concentric kit is provided with a 1-1/2” accelerator, which must be installed on the exhaust outlet when this kit is used
with this furnace.
