Lennox ML193UHE Series Unit Information page 35

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 43 and FIGURE 44 shows typical terminations.
1 - Exhaust piping must terminate straight out or up as
shown. The termination pipe must be sized as listed
in table 16.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)
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.
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 43
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) kit 15Z70 (Canada) to
install 2" or 3" PVC exhaust piping through the floor joists
and into the crawl space. See figure below.
This kit can also be used as a supplemental drain for in-
stallations with condensate run back in the vent pipe (ie.
long horizontal runs, unconditioned spaces, etc.).
UNCONDITIONED
ATTIC SPACE
Page 35
NON-DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
Minimum 12" (305MM)
above chimney top
plate or average snow
accumulation
SHEET
METAL TOP
PLATE
INSULATE
TO FORM
SEAL
FIGURE 44
Venting In A Crawl Space
Basement Floor
STRAIGHT-CUT OR
ANGLE-CUT IN DIRECTION
OF ROOF SLOPE
SHOULDER OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
EXTERIOR
PORTION OF
CHIMNEY
KIT 51W18
(USA)
KIT 15Z70
(CANADA)