Rinnai E75CN - Manual (Page 36)

Installation & Servicing Instructions Rinnai E-Series
36
Using Indoor Air For Combustion
When using air from other room(s) in the building, the total volume of the room(s) must
be of adequate volume (Greater than 50 cubic feet per 1000 Btu/hr). Each Combustion
air opening must have at least one square inch of free area for each 1000 Btuh, but
not less than 100 square inches each.
Using Outdoor Air For Combustion
Outdoor air can be provided to a confined space through two permanent openings,
one commencing within 12 in. (300mm) of the top and one commencing within 12”
(300mm) of the bottom, of the confined space. The openings shall communicate to
the outside by one of two ways:
directly through horizontal ducts
indirectly through vertical ducts
When communicating directly with the outdoors through horizontal ducts,
each opening shall have a minimum free area of 1 in2/2000 Btu/hr (1100 mm2/
kW) of total input rating of all appliances in the confined space.
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 con-
nected.
When communicating indirectly with the outdoors through vertical ducts,
each opening shall have a minimum free area of 1 in2/4000 Btu/hr (550 mm2/
kW) of total input rating of all appliances in the confined space. Combus-
tion air to the appliance can be provided from a well ventilated attic or crawl
space.
OUTLET AIR DUCT
INLET AIR DUCT
Gas Vent / Boiler Exhaust
BOILER
OUTLET
AIR
INLET
AIR
Ventilation Louvers for
unheated crawl space
Gas Vent / Boiler Exhaust
BOILER
OUTLET
AIR
INLET AIR DUCT
[Ends 1Ft (300mm)
above floor]
Gas Vent / Boiler Exhaust
BOILER
Louvers and grills figure 18