508146-01
Issue 2051
Page
39
of 7
0
General Guidelines for Vent Terminations
In Direct Vent applications, combustion air is taken from
outdoors and the flue gases are discharged to the
outdoors. The
GUH97M
is then classified as a direct vent,
Category IV gas furnace.
In 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 27. In addition, position termination so it is free
from any obstructions and 12” above the average snow
accumulation.
At vent termination, care must be taken to maintain
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 because
the condensate can damage the painted coating.
NOTE:
See Table 23 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
Armaflex or equivalent. In extreme cold climate areas,
3/4” (19mm Armaflex or equivalent may be necessary.
Insulation must be protected from deterioration. Armaflex
with UV protection is permissable. Basements or other
enclosed 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
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).
IMPORTANT