Rheem 05EAUER Installation Instructions Manual page 12

FIGURE 8
COMBUSTION AIR FITTING – NON-ATTIC COMBUSTION AIR PULL, GPN & GPP ONLY
6" MIN.
GROUND OR
SHELF SURFACE
B: Method 1
Provide two permanent openings,
one located within 12 inches of the
top and one located within 12
inches of the bottom of the
enclosure. Each opening shall
communicate directly, or by ducts,
with the outdoors or spaces (crawl
or attic) that freely communicate
with the outdoors.
a. Where directly communicating
with the outdoors or where
communicating to the outdoors
through VERTICAL DUCTS,
each opening shall have a
minimum free area of 1 square
inch for each 4000 BTUH of
total appliance input rating in the
enclosure. Here are typical duct
sizes:
VERTICAL OUTDOOR AIR
OPENING DIMENSIONS
BTUH Free Area
Input Each Opening
50,000 12.50 sq. inches
75,000 18.75 sq. inches
100,000 25.00 sq. inches
125,000 31.25 sq. inches
150,000 37.50 sq. inches
12
ATTACH OPTIONAL DOUBLE ELBOW TO TOP INLET
AIR OPENING TO PREVENT ACCIDENTAL BLOCKAGE
OF INTAKE OPENING. THIS IS NOT A REQUIREMENT.
(SEE PREVIOUS PAGE.) SINGLE ELBOW IS ALLOWED
BUT MAY NOT PREVENT DEBRIS FROM BEING
DROPPED INTO THE FURNACE.
6" MININUM
CLEARANCE
#8 SCREWS
b. Where communicating with
outdoors through HORIZONTAL
DUCTS, each opening shall have
a minimum free area of 1 square
inch for each 2000 BTUH of total
input rating for all equipment in
the enclosure. Here are typical
duct sizes:
HORIZONTAL OUTDOOR AIR
OPENING DIMENSIONS
BTUH
Input
50,000 25.00 sq. inches
75,000 37.50 sq. inches
100,000 50.00 sq. inches
125,000 62.50 sq. inches
150,000 75.00 sq. inches
B: Method 2
One permanent opening, located within
12 inches of the top of the enclosure,
shall be permitted where the
Round
equipment has clearances of at least 1
Pipe Size
inch from the sides and back and 6
4"
inches from the front of the appliance.
5" The opening shall directly
communicate with the outdoors or
6"
communicate through a vertical or
7"
horizontal duct to the outdoors or
7"
spaces (crawl or attic) that freely
communicate with the outdoors and
have a minimum free area of:
EXHAUST
PVC
DOUBLE
ELBOW
METAL FLUE
PIPE ONLY
#8 SCREWS
Free Area Round
Each Opening Pipe Size
6"
7"
8"
9"
10"
a. One square inch for each 3000
BTUH of the total input rating of all
equipment located in the enclosure,
AND
b. Not less than the sum of the areas
of all vent connectors in the confined
space.
IMPORTANT: If the furnace is in a
location with an exhaust fan, there
must be sufficient ventilation to prevent
the exhaust fan from creating a
negative pressure in the room.
Combustion air openings must NOT
BE RESTRICTED in any manner.
CONSULT LOCAL CODES FOR
SPECIAL REQUIREMENTS.