Rinnai RU199i Installation Instructions Manual page 19

Louvers and Grills
When sizing the permanent opening, consideration must
be taken for the design of the louvers or grills to maintain
the 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
10 in.
(254 mm)
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. (305 mm) of the top of the confined space and the
lower opening shall be within 12 in. (305 mm) of the
bottom of the confined space. Openings must be
positioned as to never be obstructed.
Using Outdoor Air For Combustion
Outdoor air can be provided to a confined space through
two permanent openings, one commencing within 12 in.
(305 mm) of the top and one commencing within 12 in.
(305 mm) of the bottom of the confined space. The
openings shall communicate to the outside by one of two
ways.
PVC/CPVC Common Venting Installation Instructions
Copyright © 2018 Rinnai America Corporation. All Rights Reserved.
2
2
12 in. (305 mm)
(Be sure to maintain 12 in. (305 mm) above grade or
anticipated snow level)
Vent termination per ANSI Z223.1/NFPA 54. For
clearances not specified in ANSI Z223.1/NFPA 54,
clearances are in accordance with local installation
codes and the requirements of the gas supplier.
Exhaust
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