Rheem RGRK-12ERAJS Series Installation Instructions Manual page 19

Method 2 (not shown)
One permanent opening, located
within 12 inches of the top of the
enclosure, shall be permitted
where the equipment has
clearances of at least 1 inch from
the sides and back and 6 inches
from the front of the appliance.
The opening shall directly
communicate with the outdoors or
communicate through a vertical or
horizontal duct to the outdoors or
spaces (crawl or attic) that freely
communicate with the outdoors,
and shall have a minimum free
area of:
a. 1 square inch for each 3,000
BTUH of the total input rating of all
equipment located in the enclosure
and
FIGURE 13
COMBUSTION AIR FITTING
UPFLOW
ATTACH DOUBLE ELBOW TO TOP INLET
AIR OPENING OR 90° ELBOW TO SIDE
INLET AIR OPENING TO PREVENT
ACCIDENTAL BLOCKAGE OF INTAKE
OPENING. PLUG OPENING NOT USED.
EXHAUST
BTUH Free Area
Input Each Opening
45,000 15.00 square inches
60,000 16.67 square inches
75,000 25.00 square inches
90,000 30.00 square inches
105,000 35.00 square inches
120,000 40.00 square inches
b. Not less than the sum of the
areas of all vent connectors in the
confined space.
If unit is installed where there is an
exhaust fan, sufficient ventilation
must be provided to prevent the
exhaust fan from creating a negative
pressure.
Combustion air openings must not be
restricted in any manner.
2" PVC
DOUBLE
ELBOW
TOP
OPTION
2" PVC ELBOW
SIDE
OPTION
I337
CONSULT LOCAL CODES FOR
Round Pipe
SPECIAL REQUIREMENTS.
Size
4"
CONNECTION TO
5"
FURNACE
6"
6"
IMPORTANT: When indoor
7" combustion air is used, the inlet air
opening at the furnace must be
7"
protected from accidental blockage.
(See Figure 13).
DOWNFLOW/HORIZONTAL
2" PVC
DOUBLE
ATTACH DOUBLE ELBOW TO INTAKE AIR
COLLAR AND SECURE WITH TWO SHEET
ELBOW*
METAL SCREWS TO PREVENT ACCIDENTAL
BLOCKAGE OF INTAKE AIR OPENING.
PREDRILL FOR SCREWS.
COMBUSTION AIR
*NOTE: WHEN FURNACE IS INSTALLED IN A HORIZONTAL POSITION
ONLY ONE 90° ELBOW IS REQUIRED. INSTALL THE ELBOW SO THE
OPEN END IS POINTED DOWNWARD.
EXHAUST
I336
19