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Installation & Operation Manual
2 Venting (continued)
25
Multiple horizontal or vertical direct vent installations
The combustion air inlet caps for multiple appliance installations must maintain the same minimum clearance from the closest
vent cap installed within a 10 foot radius of the point of flue gas termination as specified in single appliance installations.
Multiple flue outlet caps may be installed side by side and multiple air inlet caps may be installed side by side, but the minimum
clearance of a 3 foot (0.91m) horizontal radius and 12 inches (0.30m) below the closest flue outlet to the air inlet cap must be
maintained. All clearance and installation requirements in this section and the applicable portions of the Category IV General
Venting section must be maintained on multiple appliance installations.
Horizontal Air Inlet: Vent options C, E, F, & I
Sidewall combustion air inlet
The sidewall termination caps for both the flue products and combustion air must be purchased from the appliance
manufacturer.
The part numbers for the required sidewall termination kit are listed under each designated table. Each kit includes both the
special combustion air inlet cap and the sidewall flue cap for installation on an exterior sidewall. The sidewall air inlet cap
supplied in the kit is sized to provide combustion air for a single appliance only.
Location of a sidewall air inlet cap
Incorrect installation and/or location of the air inlet cap can allow the discharge of flue products to be drawn into the
combustion process on the heater. This can result in incomplete combustion and potentially hazardous levels of carbon
monoxide in the flue products. This will cause operational problems with the heater and possible spillage of flue products that
can cause personal injury, death, or property damage.
The termination point of the sidewall air inlet must be installed a minimum of 12 inches (0.30m) above ground level and above
normal levels of snow accumulation.
The point of termination for the sidewall combustion air inlet cap MUST be located a minimum of 3 feet (0.91m) horizontally
and 12 inches (0.30m) below the point of flue gas termination (vent cap) if it is located within a 10 foot (3.05m) radius of the
flue outlet.
The combustion air inlet caps for multiple appliance installations must maintain the same minimum clearance from the closest
vent cap installed within a 10 foot radius of the point of flue gas termination as specified in single appliance installations.
Figure 2-5_Horizontal Air Inlet Clearances
The combustion air inlet cap must not be installed closer
than 10 feet (3.05m) from an inside corner of an L-shaped
structure.
The combustion air cap assembly used MUST adequately
protect the combustion air inlet from wind and weather.
Combustion air supplied from outdoors must be free of
contaminants (see Combustion and Ventilation Air, page 10).
To prevent recirculation of flue products into the
combustion air inlet, follow all instructions in this section.