Lennox 95G2UHV Installation Instructions Manual page 32

Details of Exhaust Piping Terminations for Non-
Direct Vent Applications
Exhaust pipes may be routed either horizontally through
an outside wall or vertically through the roof. In attic or
closet installations, vertical termination through the roof
is preferred. Figure 45 through Figure 48 show typical
terminations.
1. Exhaust piping must terminate straight out or up as
shown. The termination pipe must be sized as listed
in Table 7. The specified pipe size ensures proper
velocity required to move the exhaust gases away
from the building.
2. On field supplied terminations for side wall exit,
exhaust piping may extend a maximum of 12 inches
(305 mm) for 2" PVC and 20" (508 mm) for 3" (76 mm)
PVC beyond the outside wall. See Figure 44.
3. If exhaust piping must be run up a sidewall to position
above snow accumulation or other obstructions, piping
must be supported every 24" (610 mm) as shown in
Figure 47. When exhaust piping must be run up an
outside wall, any reduction in exhaust pipe size must
be done after the final elbow.
12" (305MM)
ABOVE AVE.
SNOW
ACCUMULATION
3" (76MM) OR
2" (51MM) PVC
PROVIDE SUPPORT
FOR EXHAUST LINES
Figure 45. Non-Direct Vent Roof Termination Kit
(15F75 or 44J41)
FIELD-PROVIDED
REDUCER MAY BE
REQUIRED TO
ADAPT DIFFERENT
VENT PIPE SIZE TO
TERMINATION
SIZE TERMINATION
PER EXHAUST PIPE
TERMINATION SIZE
REDUCTION TABLE
Figure 46. Non-Direct Vent Field Supplied Wall
Termination
Page 32 of 58
SIZE PER EXHAUST PIPE
TERMINATION SIZE
REDUCTION TABLE
UNCONDITIONED
ATTIC SPACE
Issue 1933
FIELD-PROVIDED
REDUCER MAY BE
REQUIRED TO
ADAPT DIFFERENT
VENT PIPE SIZE TO
TERMINATION
* Use wall support every 24" (610 mm). Use two supports of extension is greater than 24"
(610 mm) but less than 48" (1219 mm).
Figure 47. Non-Direct Vent Field Supplied Wall
Termination Extended
Minimum 12" (305MM)
above chimney top
plate or average snow
accumulation
SHEET
METAL TOP
PLATE
INSULATE
TO FORM
SEAL
* SIZE TERMINATION PIPE
PER EXHAUST PIPE TERMINATION
SIZE REDUCTION TABLE
NOTE:
Do not discharge exhaust gases directly into any chimney or
vent stack. If vertical discharge through an existing unused chimney
or stack is required, insert piping inside chimney until the pipe open
end is above top of chimney and terminate as illustrated. In any
exterior portion of chimney, the exhaust vent must be insulated.
Figure 48. Non-Direct Vent Application Using Existing
Chimney
SIZE TERMINATION
PER EXHAUST PIPE
TERMINATION SIZE
REDUCTION TABLE
STRAIGHT-CUT OR
ANGLE-CUT IN DIRECTION
OF ROOF SLOPE
SHOULDER OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
EXTERIOR
PORTION OF
CHIMNEY
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