Rinnai M060C Installation And Operation Manual page 40

WARNING
•
This boiler requires adequate combustion air for ventilation and dilution of flue gases. Failure
to provide adequate combustion 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 boiler.
•
Direct Venting is recommended in unusually tight buildings or in installation locations subject
to significant negative air pressure.
IMPORTANT
Combustion air must be free of corrosive chemicals. Do not provide combustion air from
corrosive environments. 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 boiler.
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/hr, 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
the confined space.
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2
/2000 Btu/hr (1100 mm
Rinnai M-Series Condensing Boiler Combi Manual
2
/kW) of total input rating of all appliances in