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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 and fittings to be Pressure Pipe, Class E /
Class 12 / Schedule 40 or equivalent
All pipe, fittings, primer and solvent cement must conform
with Australian standards. The solvent shall be free flow-
ing and contain no lumps, undissolved particles or any for-
eign 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.
CAUTION
Solvent cements for plastic pipe are flammable liq-
uids 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 4 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 or ABS.
TABLE 4
OUTDOOR TERMINATION KITS AND CORRESPONDING EQUIVALENCIES
UNIT
MODEL
VENT
PIPE
DIA.
(in.)
Vent Pipe Length Equivalency (meters)
Outdoor Ex-
haust Accel-
erator
(Dia. X
Length)
Outdoor Ex-
haust Accel-
erator
(Dia. X
Length)
40mm
(1−1/2")
Concentric
Kit
50mm (2")
Concentric
Kit
80mm (3")
Concentric
Kit
50mm (2")
Wall Plate
Kit
80mm (3")
Wall Plate
Kit
50mm (2")
Wall Ring
Kit
40mm X
305mm
50mm X
305mm
71M80
60M29
60L46
22G44
44J40
15F74
−070
50mm
1.2
Not
Allowed
3.6
Not
Allowed
Not
Allowed
1.2
1.2*
1.2
80mm
2.4
Not
Allowed
7.3
Not
Allowed
Not
Allowed
2.4
2.4*
2.4
100mm
4.3
Not
Allowed
12.8
Not
Allowed
Not
Allowed
4.3
4.3*
4.3
−090
50mm
Not
Allowed
0.3
Not
Allowed
.9
.9
Not
Allowed
0.3
0.3**
80mm
Not
Allowed
0.6
Not
Allowed
1.8
1.8
Not
Allowed
0.6
0.6**
100mm
Not
Allowed
1.2
Not
Allowed
3.7
3.7
Not
Allowed
1.2
1.2**
−110
80mm
Not
Allowed
0.6
Not
Allowed
1.8
1.8
Not
Allowed
0.6
0.6
100mm
Not
Allowed
1.2
Not
Allowed
3.7
3.7
Not
Allowed
1.2
1.2
−135
80mm
Not
Allowed
1.8
Not
Allowed
Not
Allowed
4.6
Not
Allowed
1.8
Not
Allowed
100mm
Not
Allowed
3.0
Not
Allowed
Not
Allowed
7.6
Not
Allowed
3.0
Not
Allowed
*Requires field−provided and installed 40mm exhaust
accelerator.
**Requires field−provided and installed 50mm exhaust
accelerator.
