Lennox G21Q Series Installation Instructions Manual page 12

NOTE - - Care must be taken to avoid recirculation
of exhaust back into intake pipe.
7 - - On field supplied terminations, the minimum sep-
aration distance between the end of the exhaust
pipe and the end of the intake pipe is 8” (203mm).
8 - - If intake and exhaust piping must be run up a side
wall to position above snow accumulation or other
obstructions. Piping must be supported every 3 ft.
(.91m) as shown in figure 6. Refer to figures 12 and
13 for proper piping method. WTK wall termina-
tion kit must be extended for use in this applica-
tion. See figure 16 or use kit WTKX shown in figure
17. When exhaust and intake piping must be run
up an outside wall, the exhaust piping is reduced
to 1- -1/2” (38mm) after the final elbow. The intake
piping may be equipped with a 90
down. Using turndown will add 5 ft. (1.5m) to the
equivalent length of the pipe.
1/2 (12.7) FOAM INSULATION
IN UNCONDITIONED SPACE
TOP VIEW
WALL TERMINATION
(22G44) LB- -49107CD for 2 (50.8) Venting
(44J40) LB- -65701A for 3 (76.2) Venting
),*85(
EXHAUST
TERMINATION
INTAKE
TERMINATION
EXHAUST
CONCENTRIC ROOFTOP TERMINATION
(60G77) LB- -49107CE for 2 (50.8) Venting Only
),*85( 
-
elbow turn-
Inches(mm)
OUTSIDE WALL
Optional Turndown
Shown
(Intake Only)
12 (305) ABOVE
AVERAGE SNOW
ACCUMULATION
Inches (mm)
INTAKE
Combustion air intake inlet and exhaust outlet
should not be located within 6 ft. (1.8m) of dryer
vent or combustion air inlet or outlet of another
appliance. Piping should not exit less than 3 ft.
(.91m) from opening into another building.
For Canadian Installations Only:
In accordance to CAN/CGA- -B149.1 and .2, the
minimum allowed distance between the combus-
tion air intake inlet and the exhaust outlet of other
appliances shall not be less than 12” (305mm).
3DJH 
IMPORTANT
IMPORTANT