Lennox ML193UH Installation Instructions Manual page 28

DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
8" - 12"
(203mm - 305mm)
Minimum 12" (305MM)
INSULATION (optional)
above chimney top
plate or average snow
accumulation
INSULATE
TO FORM
NOTE - Do
tical discharge through an existing unused chimney or stack is required, insert piping
inside
trated. In any exterior portion of chimney, the exhaust vent must be insulated.
FIGURE 41
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 42 and FIGURE 43 show typical ter-
minations.
1 - Exhaust piping must terminate straight out or up as
shown. The termination pipe must be sized as listed
in table 8.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
(305mm) for 2" PVC and 20 inches (508mm) for 3"
(76mm) PVC beyond the outside wall.
12" (305mm)
ABOVE AVE.
SNOW
ACCUMULATION
3" (76mm) OR
2" (51mm) PVC
PROVIDE SUPPORT
FOR EXHAUST LINES
NON-DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
FIGURE 42
3 - If exhaust piping must be run up a side wall
to position above snow accumulation or other
obstructions, piping must be supported every 24
inches (610mm). When exhaust piping must be run
up an outside wall, any reduction in exhaust pipe
size must be done after the final elbow.
4 - Distance between exhaust pipe terminations on
multiple furnaces must meet local codes.
STRAIGHT-CUT OR
ANGLE-CUT IN DIRECTION
OF ROOF SLOPE *
3" - 8"
(76mm-
203mm)
SHOULDER OF FITTINGS
INTAKE PIPE
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
SHEET
ALTERNATE
METAL TOP
INTAKE PIPE
PLATE
3" - 8"
(76mm-
203mm)
EXTERIOR
PORTION OF
SEAL
CHIMNEY
UNCONDITIONED
ATTIC SPACE
NOTE - Do not discharge exhaust gases directly into any
chimney or vent stack. If vertical discharge through an ex-
isting 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 por-
tion of chimney, the exhaust vent must be insulated.
NON-DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
Minimum 12" (305MM)
above chimney top
plate or average snow
accumulation
INSULATE
TO FORM
SEAL
NOTE - Do
tical discharge through an existing unused chimney or stack is required, insert piping
inside
trated. In any exterior portion of chimney, the exhaust vent must be insulated.
Crawl Space and Extended Horizontal Venting
Lennox provides kit 51W18 (USA) and kit 15Z70 (Cana-
da) to install 2" or 3" PVC exhaust piping through the floor
joists and into the the crawl space. See figure below. This
kit can also be used as a supplemental drain for installa-
tions with condensate run back in the vent pipe (ie. long
horizontal runs, unconditioned spaces, etc.).
KIT 51W18
(USA)
KIT 15Z70
(CANADA)
Page 28
STRAIGHT-CUT OR
ANGLE-CUT IN DIRECTION
OF ROOF SLOPE
SHOULDER OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
SHEET
METAL TOP
PLATE
EXTERIOR
PORTION OF
CHIMNEY
FIGURE 43
Venting In A Crawl Space
Basement Floor