Page 22
Crawl Space and Extended Horizontal VentingGenera
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 27. 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.).
Venting In A Crawl Space
Basement Floor
KIT 51W18
(USA)
KIT 15Z70
(CANADA)
FIGURE 26
General Guidelines for Vent Terminations
In Direct Vent applications, combustion air is taken from
outdoors and the flue gases are discharged to the out
-
doors. The SLP99DFV is classified as a direct vent, Cate
-
gory IV gas furnace.
In Direct Vent applications, the vent termination is limited
by local building codes. In the absence of local codes, re-
fer to the current National Fuel Gas Code ANSI Z223-1/
NFPA 54 in U.S.A., and current CSA-B149 Natural Gas
and Propane Installation Codes in Canada for details.
Position termination according to location given in FIG-
URE 25. In addition, position termination so it is free from
any obstructions and 12” above the average snow accu-
mulation.
At vent termination, care must be taken to maintain protec-
tive coatings over building materials (prolonged exposure
to exhaust condensate can destroy protective coatings).
It is recommended that the exhaust outlet not be located
within 6 feet (1.8m) of an outdoor AC unit because the
condensate can damage the painted coating.
NOTE -
See TABLE 9 for maximum allowed exhaust pipe
length without insulation in unconditioned space during
-
winter design temperatures below 32°F (0°C). If required
exhaust pipe should be insulated with 1/2” (13mm) Ar
-
maflex or equivalent. In extreme cold climate areas, 3/4”
(19mm) Armaflex or equivalent may be necessary. Insu
-
lation must be protected from deterioration. Armaflex with
UV protection is permissable. Basements or other en
-
closed areas that are not exposed to the outdoor ambient
temperature and are above 32 degrees F (0°C) are to be
considered conditioned spaces.
IMPORTANT
Do not use screens or perforated metal in exhaust
terminations. Doing so will cause freeze-ups and
may block the terminations.
IMPORTANT
For Canadian Installations Only:
In accordance to CSA International B149 installation
codes, the minimum allowed distance between the
combustion air intake inlet and the exhaust outlet
of other appliances shall not be less than 12 inches
(305mm).
Summary of Contents for SIGNATURE SLP99DF070V36
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