Rinnai Demand Duo R-Series Installation And Operation Manual page 21

This water heater requires adequate combustion
air for ventilation and dilution of flue gases.
Failure to provide adequate combustion air can
result in unit failure, fire, explosion, serious bodily
injury or death. Use the following methods to
ensure adequate combustion air is available for
correct and safe operation of this water heater.
IMPORTANT
Combustion air must be free of corrosive
chemicals. DO NOT provide combustion air
from corrosive environments. Appliance
failure due to corrosive air is not covered by
warranty.
Combustion air must be free of 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 combustion air in 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.
Corrosive fumes, sometimes found in hair/ nail
salons, spas, or other industries exposed to toxic
fumes, may be released through these vents
when not in operation. Chemicals that are
corrosive in nature should not be stored or used
near the water heater or vent termination.
An unconfined space is defined in National Fuel
Gas Code, ANSI Z223.1/NFPA 54, and/or CSA
B149.1 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.
Demand Duo™ R-Series (REC) Installation and Operation Manual
Figure 10
32 ft.
(9.7 m)
Note: 10 ft. Ceiling
32 ft. x 32 ft. x 10 ft. = 10,240 ft.
3
50 ft.
x 199,000 Btu/Hr
1,000 ft.
Above calculation is an example of the minimum
required volume for Unconfined Space
(water heater only).
39 ft.
(11.8 m)
Note: 10 ft. Ceiling
39 ft. x 39 ft. x 10 ft. = 15,210 ft.
3
50 ft.
x 299,000 Btu/Hr
1,000 ft.
Above calculation is an example of the minimum
required volume for Unconfined Space
(water heater and a 100,000 BTU furnace).
32 ft.
(9.7 m)
3
3
= 9,950 ft.
39 ft.
(11.8 m)
3
3
= 14,950 ft.
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