Rinnai SENSEI RSC160i Installation And Operation Manual page 44

Room Air: Combustion Air
WARNING
air can result in unit failure, fire, explosion, serious bodily injury or death. Use the following
methods to ensure adequate combustion air is available for correct and safe operation of
this water heater.
IMPORTANT
Combustion air must be free of corrosive chemicals. Do not provide combustion air from
corrosive environment. Appliance failure due to corrosive air is not covered by warranty.
For applications containing corrosive indoor air, this appliance must be installed as direct vent. DO
NOT use room air in applications where combustion air contains acid forming chemicals such as
sulfur, fluorine and chlorine. These chemicals have been found to cause rapid damage and decay and
can become toxic when used as combustion air in gas appliances. Such chemicals can be found in,
but not limited to bleach, ammonia, cat litter, aerosol sprays, cleaning solvents, varnish, paint and air
fresheners. Do not store these products or similar products in the vicinity of this water heater.
Unconfined Space
An unconfined space is defined in National Fuel Gas Code, ANSI Z223.1/NFPA 54 as "a space whose
volume is not less than 50 cubic feet per 1000 Btu/hr (4.8 m³ per kW per hour) of the aggregate input
rating of all appliances installed in that space. Rooms communicating directly with the space in which
the appliances are installed, through openings not furnished with doors, are considered a part of the
unconfined space." If the "unconfined space" containing the appliance(s) is in a building with tight
construction, additional outside air may be required for proper operation. Outside air openings should
be sized the same as for a confined space.
Confined Space
A confined space is defined in the National Fuel Gas Code, ANSI Z223.1/NFPA 54 as "a space
whose volume is less than 50 cubic feet per 1000 Btu/hr (4.8 m³ per kW per hour) of the aggregate
input rating of all appliances installed in that space." Examples include a small room, closet, alcove,
utility room, etc. A confined space must have two combustion air openings. Size the combustion air
openings based on the BTU input for all gas utilization equipment in the space and the method by
which combustion air is supplied.
Using Indoor Air For Combustion: When using air from other room(s) in the building, the total volume
of the room(s) must be of adequate volume (Greater than 50 cubic feet per 1000 Btu/hr). Combustion
air openings between joining rooms must have at least 1 square inch of free area for each 1000 Btu/h,
but not less than 100 square inches each.
Using Outdoor Air For Combustion
Outdoor air can be provided to a confined space through two permanent openings, one commencing
within 12 in. (0.30 m) of the top and one commencing within 12 in. (0.30 m) of the bottom, of the
confined space. The openings shall communicate to the outside by one of two ways.
When communicating directly with the outdoors through horizontal ducts, each opening shall have
a minimum free area of 1 in
confined space.
NOTE
If ducts are used, the cross sectional area of the duct must be greater than or equal to the required
free area of the openings to which they are connected.
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This water heater requires adequate combustion air for ventilation
and dilution of flue gases. Failure to provide adequate combustion
/2000 Btu/hr (1100 mm²/kW) of total input rating of all appliances in the
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Rinnai Tankless Water Heater Installation and Operation Manual