The sidewall air inlet cap must not be
installed closer than 10 feet (3.05m) from
an inside corner of an L shaped structure.
The sidewall air inlet cap assembly must
adequately protect the combustion air inlet
from wind and weather.
Rooftop Combustion Air Inlet
The air inlet cap for the rooftop combustion
air inlet is not supplied by the manufacturer
and must be purchased locally. The air inlet
cap consists of two 90° elbows installed at
the point of termination for the air inlet pipe.
Location of Rooftop Air Inlet Cap
Incorrect installation and/or location of the
air inlet cap may allow the discharge of flue
products to be drawn into the combustion
process of the unit. This may result in
incomplete combustion and potentially
hazardous levels of carbon monoxide in the
flue products. This will cause operational
problems with the unit and may result in
possible spillage of flue products that can
cause personal injury, death or property
damage.
The termination point of the rooftop air inlet
must be located a minimum of 12" (0.30 m)
above the roof or above normal levels of
snow accumulation. The point of
termination for the air inlet cap must be
located a minimum of 3 feet (0.91m) below
any point of flue gas termination if the air
inlet is located within a 10 foot (3.05m)
radius of the flue outlet.
The rooftop air inlet cap must not be
installed closer than 10 feet (3.05 m) from
an inside corner of an L shaped structure.
The rooftop air inlet cap assembly must
adequately protect the combustion air inlet
from wind and weather.
DirectAire Systems
A DirectAire vent system uses a flue to the
sidewall or rooftop with a separate combustion
air inlet pipe to the outdoors. The DirectAire vent
system may terminate the flue and the
combustion air inlet pipe in different pressure
zones in any one of three configurations as
shown in figures 13, 15 and 16.
• The flue on the rooftop and combustion
air inlet on the sidewall. (FIG. 13)
• The flue on the sidewall and combustion
air inlet on the rooftop. (FIG. 15)
• The flue on the sidewall and the combustion
air inlet on a sidewall other than the
sidewall where the flue is located
. (FIG. 16)
Units with ON/OFF burner controls utilizing
Category I, negative draft venting may be
configured as a DirectAire system and may
have both the flue and air inlet terminated
on the rooftop in the same pressure zone.
(See FIG. 14)
DirectAire vent systems require the
installation of specific venting materials.
Rooftop flue gas termination caps and
combustion air inlets must be purchased
locally. Sidewall flue gas termination caps
and combustion air inlets must be purchased
from the appliance manufacturer as per
CSA International requirements.
L o c h i n v a r
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