2
Non-Direct Vent
Combustion Air (Continued)
Louvers and Grills
When sizing the permanent opening consideration must be taken for the design of the louvers or grills to maintain the
required free area required for all gas utilizing equipment in the space. If the free area of the louver or grill design is
not available, assume wood louvers will have 25% free area and metal louvers or grills will have 75% free area. Under
no circumstance should the louver, grill or screen have openings smaller than 1/4 in.
Example: Wood: 10 in. x 12 in. x 0.25 = 30 in.
Metal: 10 in. x 12 in. x 0.75 = 90 in.
Location
To maintain proper circulation of combustion air two permanent
openings (one upper, one lower) must be positioned in confined
spaces. The upper shall be within 12 in. (0.30 m) of the top of the
confined space and the lower opening shall be within 12 in. (0.30 m) of
the bottom of the confined space. Openings must be positioned as to
never be obstructed.
NOTICE
Combustion air provided to the appliance should not be taken from any area of the structure that may produce a
negative pressure (i.e. exhaust fans, powered ventilation fans).
WARNING
TO PREVENT POSSIBLE PERSONAL INJURY OR DEATH DUE TO ASPHYXIATION, COMMON VENTING WITH OTHER
MANUFACTURER'S INDUCED DRAFT APPLIANCES IS NOT ALLOWED.
Checklist for Combustion Air and Venting Requirements
□
Verify all combustion air opening sizes are correct.
□
Ensure that the Combustion Air Requirements are followed that will provide sufficient combustion air for the
appliance.
□
DO NOT use room air for combustion in applications where the indoor air is corrosive.
□
Verify that adequate combustion air is available for all appliances installed in the space.
□
Installation complies with National Fuel Gas Code, ANSI Z223.1/NFPA 54 as well as local and state
regulations therein.
36
(Room Air)
2
2
Rinnai Tankless Water Heater Installation and Operation Manual
12 in.
(300 mm)
10 in.
(250 mm)