Rheem RGLK, Installation Instructions Manual

Page: 12 / 36

CONSULT LOCAL CODES FOR
SPECIAL REQUIREMENTS.
Air openings in furnace casing front,
return air grilles, and warm air registers
must not be obstructed.
Btuh Free Area Round Pipe
Input Each Opening Size
50,000 25 Square Inches 6
(
75,000 37.5 Square Inches 7
(
100,000 50 Square Inches 8
(
125,000 62.5 Square Inches 9
(
150,000 75 Square Inches 10
(
Method 2
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
12
FIGURE 8
OUTSIDE AIR USING A HORIZONTAL INLET & OUTLET
b. Not less than the sum of the areas
of all vent connectors in the confined
space.
Here are some typical sizes.
Btuh Free Area Round Pipe
Input Each Opening Size
50,000 16.67 Square Inches 6
(
75,000 25 Square Inches 7
(
100,000 33.33 Square Inches 8
(
125,000 41.67 Square Inches 9
(
150,000 50 Square Inches 10
(
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 in
the room.
Combustion air openings must not be
restricted in any manner.