Lennox DAVE SIGNATURE SL297UHNV Installation Instructions Manual page 18

TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN HORIZONTAL DIRECT OR NON-DIRECT VENT
General Guidelines for Vent Terminations
In Non-Direct Vent applications, combustion air is taken
from indoors or ventilated attic or crawlspace and the flue
gases are discharged to the outdoors. The SL297UHNV
is then classified as a non-direct vent, Category IV gas
furnace.
In Direct Vent applications, combustion air is taken from
outdoors and the flue gases are discharged to the out-
doors. The SL297UHNV is then classified as a direct vent,
Category IV gas furnace.
In both Non-Direct Vent and Direct Vent applications, the
vent termination is limited by local building codes. In the
absence of local codes, refer 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 figure
23. In addition, position termination so it is free from any
obstructions and 12" above the average snow accumula-
tion. At vent termination, care must be taken to maintain
APPLICATIONS
12" max.
EXHAUST
2"
2"
Appliance
Adaptor
2"
INTAKE
2"
DO NOT transition
from smaller to larger
pipe in horizontal runs
of exhaust pipe.
* When transitioning up in pipe size, use the shortest length of 2" PVC pipe possible.
(RIGHT HAND DISCHARGE SHOWN)
2"
or 2"
2"
45°
MAX
SIDE VIEW
Figure 21
protective 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 be-
cause the condensate can damage the painted coating.
NOTE - See table 7 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.
Do not use screens or perforated metal in exhaust or
intake terminations. Doing so will cause freeze-ups and
may block the terminations.
Page 18
EXHAUST
INTAKE
2"
45°
MAX
2"
IMPORTANT
3"
*2"
*2"
Appliance
Adaptor