Rheem RTGH-C95XLP Use And Care Manual page 49

Combination Indoor and
Outdoor Combustion Air
The use of a combination of indoor and outdoor
combustion air shall be in accordance with the following:
(1) Indoor openings. Where used, openings connecting
the interior spaces shall comply with "Indoor
Combustion Air"
(2) Outdoor opening(s) location. Outdoor opening(s) shall
be located in accordance with "Outdoor Combustion
Air"
(3) Outdoor opening(s) size. The outdoor opening(s) size
shall be calculated in accordance with the following:
(a) The ratio of the interior spaces shall be the
available volume of all communicating spaces divided
by the required volume.
(b) The outdoor size reduction factor shall be 1 minus
the ratio of interior spaces.
(c) The minimum size of outdoor opening(s) shall
be the full size of outdoor opening(s) calculated in
accordance with "Outdoor Combustion Air", multiplied
by the reduction factor. The minimum dimension of air
openings shall not be less than 3" (8 cm).
Louvers, Grilles, and Screens
The required size of openings for combustion, ventilation,
and dilution air shall be based on the net free area of each
opening. Where the free area through a design of louver,
grille, or screen is known, it shall be used in calculating
the size opening required to provide the free area speci-
fied. Where the louver and grille design and free area are
not known, it shall be assumed that wood louvers have 25
percent free area, and metal louvers and grilles have 75
percent free area. Nonmotorized louvers and grilles shall
be fixed in the open position.
NOTICE:
Protective screening for the openings MUST NOT be smaller
than 1/4"mesh to prevent clogging by lint or other debris.
Refer to the latest edition of National Fuel Gas Code,
ANSI Z223.1/NFPA 54 for additional information for the
combustion air requirements.
Corrosive Atmosphere
The water heater should not be installed near an air sup-
ply containing halogenated hydrocarbons where contami-
nants can enter the combustion air supply.
Avoid installing a water heater in any of the following
locations: beauty shops, dry-cleaning establishments,
photo processing labs, and storage areas for liquid and
powdered bleaches or swimming pool chemicals. These
locations often contain such halogenated hydrocarbons.
The air supply containing halogenated hydrocarbons is
safe to breathe, but when passed through a gas flame,
corrosive elements are released that will shorten the life
of any gas-burning appliance.
Propellants from common spray cans or gas leaks from
A/C and refrigeration equipment are highly corrosive after
passing through a flame.
NOTICE:
The water heater warranty is void when the failure is due to
operation in corrosive conditions.
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