Installation Guide

42 Rinnai Tankless Water Heater Installation and Operation Manual
Room Air: Intake Air
For applications containing corrosive indoor air, this appliance must be installed as direct vent. DO
NOT use room air in applications where intake 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 intake air for 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 intake air openings. Size the intake
air openings based on the BTU input for all gas utilization equipment in the space and the method by
which intake 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). Intake 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.
2
/2000 Btu/hr (1100 mm
2
/kW) of total input rating of all appliances in the
confined space.
This water heater requires adequate air for ventilation and dilution of flue
gases. Failure to provide adequate air can result in unit failure, fire,
explosion, serious bodily injury or death. Use the following methods to ensure adequate air is
available for correct and safe operation of this water heater.
WARNING
IMPORTANT
Intake air must be free of corrosive chemicals. Do not provide air from corrosive environment.
Appliance failure due to corrosive air is not covered by warranty.
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.