Installation / Operation Instruction Manual

19
Combustion Air Supply
Provide adequate air for combustion and ventilation. An insufficient supply of air
will cause recirculation of combustion products resulting in air contamination
that may be hazardous to life. Such a condition often will result in a yellow,
luminous burner flame, causing carbon build up or sooting of the combustion
chamber, burners, and flue tubes with possible damage to the water heater.
When an exhaust fan is installed in the same room with a water heater,
sufficient openings for air must be provided in the walls. Undersized openings
will cause air to be drawn into the room through the venting, causing
recirculation of combustion products.
Unconfined Spaces
In unconfined spaces in buildings, infiltration may be adequate to provide air for
combustion, ventilation, and dilution of flue gases. However, in buildings of tight
construction (heavily insulated, weather stripping, caulked, vapor barrier, etc.)
additional air may need to be provided using the methods described below.
Confined Spaces
Confined spaces are spaces defined as having less than 50 ft
3
/1,000 BTU/hr
(4.8 m
3
/kW) of input.
IMPORTANT
The flow of combustion and ventilating air must not be obstructed.