Lennox G21Q Series Installation Instructions Manual page 8

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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 sol-
vent cement when making joints. Good ventila-
tion should be maintained to reduce fire hazard
and to minimize breathing of solvent vapors.
Avoid contact of cement with skin and eyes.
Primers and solvents must meet ASTM specifications.
PVC primer is specified in ASTM F 656. Use PVC solvent
cement as specified in ASTM D 2564. Low temperature
solvent cement is recommended. Metal, plastic strap-
ping or large wire ties may be used for vent pipe hangers.
PVC pipe used for exhaust and intake lines should be
sized per table 4. Note that maximum length of vent
pipe is for one run; either intake or exhaust. Maximum
vent length given is
not
haust vents.
TABLE 4
MINIMUM DIAMETER FOR G21 VENTING
Linear Pipe
Length
(Max. Feet)
0
5 2” 2”
(1.5m) (51mm) (51mm)
10 2”
(3m) (51mm)
20 2”
(6.1m) (51mm)
30 2”
(9.1m) (51mm)
2”
35
(51mm)
(10.6m)
40 2”
(12.2m) (51mm)
50 2”
(15.2m) (51mm)
60
2- -1/2”
(18.3m) (64mm)
70 2- -1/2”
(21.3m) (64mm)
80 2- -1/2”
(24.4m) (64mm)
90 2- -1/2”
(27.4m) (64mm)
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the total length of intake + ex-
-
Number of 90 Elbows
2 4 6
2” 2” 2” 2” 2”
(51mm) (51mm) (51mm) (51mm) (51mm)
2” 2” 2”
(51mm) (51mm) (51mm)
2” 2” 2”
(51mm) (51mm) (51mm)
2” 2” 2- -1/2”
(51mm) (51mm) (64mm)
2” 2” 2- -1/2”
(51mm) (51mm) (64mm)
2” 2- -1/2” 2- -1/2”
(51mm) (64mm) (64mm)
2- -1/2” 2- -1/2” 2- -1/2”
(64mm) (64mm) (64mm)
2- -1/2” 2- -1/2” 2- -1/2”
(64mm) (64mm) (64mm)
2- -1/2” 2- -1/2” 3”
(64mm) (64mm) (76mm)
2- -1/2” 3” 3”
(64mm) (76mm) (76mm)
3” 3” 3”
(76mm) (76mm) (76mm)
-
Each 90
pipe. Two 45
-
One 45 elbow is equal to 2.5 feet (.76M) of vent pipe.
If intake and exhaust piping runs are not equal in length
and combination, the larger diameter pipe (as sized per
table 4) must be used for both runs. Regardless of the
diameter of pipe used, the standard roof and wall termi-
nations described in section D- -Intake and Exhaust Pip-
ing Terminations should be used. Exhaust piping must
terminate with 1- -1/2” (38mm) pipe.
Muffler lengths should be excluded when measuring
vent pipe runs for sizing. Vent pipe must be sized at 2”
(51mm) between unit and mufflers.
Procedure for Cementing Joints Per ASTM D2855
1 - - Measure and cut PVC pipe to desired length.
2 - - Debur and chamfer end of pipe, removing any
ridges or rough edges.
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 liberal coat of primer to inside
socket surface of fitting and male end of pipe to
depth of fitting socket.
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. Ap-
ply 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
8
pipe, and while both inside socket surface and end
2”
of pipe are wet with cement, forcefully insert end
(51mm)
of pipe into socket until it bottoms out. Turn pipe
2”
1/4 turn during assembly (but not after pipe is fully
(51mm)
2- -1/2”
inserted) to distribute cement evenly.
(64mm)
NOTE - - Assembly should be completed within 20
2- -1/2”
(64mm)
seconds after last application of cement. Hammer
2- -1/2”
blows should not be used when inserting pipe.
(64mm)
2- -1/2”
8 - - After assembly, wipe excess cement from pipe at
(64mm)
end of fitting socket. A properly made joint will
2- -1/2”
(64mm) show a bead around its entire perimeter. Any gaps
3”
may indicate a defective assembly due to insuffi-
(76mm)
cient solvent.
3”
(76mm)
9 - - Handle joints carefully until completely set.
3”
(76mm)
B - - Exhaust and Condensate Piping
3”
This unit is designed for either right or left side exit of
(76mm)
exhaust piping.
3DJH 
elbow is equivalent to 5 feet (1.5m) of vent
-
elbows are equivalent to one 90
If end is not chamfered,
-
elbow.