507581-04Page 26 of 60 Issue 2128
General Guidelines for Vent Terminations
In Non–Direct Vent applications, combustion air is taken
from indoors and the ue gases are discharged to the
outdoors. This furnace is then classied as a non–direct
vent, Category IV gas furnace.
In Direct Vent applications, combustion air is taken from
outdoors and the ue gases are discharged to the outdoors.
The furnace is then classied 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.
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
35 and Figure 43. 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 (1.8 m) of a condensing unit because
the condensate can damage the painted coating.
NOTE: See Table 6 for maximum allowed exhaust pipe
length without insulation in unconditioned space during
winter design temperature below 32° F (0° C). If required,
exhaust pipe should be insulated with 1/2” (13 mm),
Armaex or equivalent when run through an unconditional
area. In extremely cold climate areas with temperature
below 20° F (6.7° C) it is recommended that, 3/4” (19 mm)
Armaex or equivalent be used. Insulation on outside
runs of exhaust pipe should be painted or wrapped to
protect insulation from deterioration in accordance with
the insulation manufacturers recommendation. Exhaust
pipe insulation may not be necessary in some specic
applications.
NOTE: During extremely cold temperatures, below
approximately 20° F (6.7° C), units with long runs of vent
pipe through unconditioned space, even when insulated,
may form ice in the exhaust termination that prevents the
unit from operating properly. Longer run times of at least 5
minutes will alleviate most icing problems. Also, a heating
cable may be installed on exhaust piping and termination
to prevent freeze-ups. Heating cable installation kits are
available see unit specication sheets for part numbers.
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 (305
mm).
IMPORTANT
Do not use screens or perforated metal in exhaust
terminations. Doing so will cause freeze-ups and may
block the terminations.
IMPORTANT
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