Rinnai M060C Installation And Operation Manual page 41

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.
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.
Examples: 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.
IMPORTANT
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).
To prevent possible personal injury or death due to asphyxiation, common
WARNING
venting with other manufacturer's induced draft appliances is not allowed.
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Verify all combustion air opening sizes are correct.
Ensure that the Combustion Air Requirements are followed that will provide sufficient
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combustion air for the appliance.
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DO NOT use room air for combustion in applications where the indoor air is corrosive.
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Verify that adequate combustion air is available for all appliances installed in the space.
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Installation complies with National Fuel Gas Code, ANSI Z223.1/NFPA 54 as well as local
and state regulations therein.
Rinnai M-Series Condensing Boiler Combi Manual
2
2
12 in.
(300 mm)
10 in.
(250 mm)
41