Rheem 97MDV060 Series Installation Instructions Manual page 30

GENERAL VENTING REQUIREMENTS AND
GUIDELINES
NON-DIRECT VENT (cont.)
B. USING OUTDOOR AIR FOR COMBUSTION:
IMPORTANT: Do not take air from an attic space that is
equipped with power ventilation.
The confined space must communicate with the outdoors in
accordance with Methods 1 or 2 below. The minimum dimen-
sion of air openings shall not be less than 3 inches. Where
ducts are used, they shall be of the same cross-sectional
METHOD 1:
area as the free area of the openings to which they connect.
Two permanent openings, one located within 12 inches of the
top and one located within 12 inches of the bottom of the
enclosure, shall be provided. The openings shall communicate
directly, or by ducts, with the outdoors or spaces (crawl or
attic) that freely communicate with the outdoors.
T BLE 8: MINIMUM FREE RE REQUIRED
FOR E CH OPENING (WHEN TWO OPENINGS
RE USED) WITH
1. LOC TED IN CONFINED SP CE
2. USING OUTDOOR IR FOR COMBUSTION
3. COMMUNIC TING DIRECTLY TO THE
3. OUTSIDE THROUGH N OPENING OR
3. THROUGH VERTIC L DUCT.
T BLE 9: MINIMUM FREE RE REQUIRED
FOR E CH OPENING (WHEN TWO OPENINGS
RE USED) WITH
1. LOC TED IN CONFINED SP CE
2. USING OUTDOOR IR FOR COMBUSTION
3. COMMUNIC TING DIRECTLY TO THE
3. OUTSIDE THROUGH
30
FURN CE:
FURN CE:
HORIZONT L DUCT.
A. Where directly communicating with the outdoors through
vertical ducts as shown in Figure 12, each opening shall have
an opening or where communicating to the outdoors through
a minimum free area of 1 square inch for each 4,000 BTUH of
Table 8 below specifies the minimum area for each of the 2
total appliance input rating of all equipment in the enclosure.
combustion air openings and minimum round duct diameter
for direct openings and vertical ducting only.
B. Where communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of 1
ing of all equipment in the enclosure (see Figure 13). Table 9
square inch for each 2,000 BTUH of total appliance input rat-
specifies the minimum area for each of the 2 combustion air
openings and minimum round duct diameter for horizontal
METHOD 2:
ducting only.
One permanent opening located within 12 inches of the top
T BLE 10: MINIMUM FREE RE REQUIRED
FOR N OPENING (WHEN ONE OPENING IS
USED) WITH FURN CE:
1. LOC TED IN CONFINED SP CE
2. USING OUTDOOR IR FOR COMBUSTION
3. COMMUNIC TING DIRECTLY TO THE
3. OUTSIDE.
FIGURE 11
NON-DIRECT VENT
AIR FROM
HEATED
SPACE
ST-A1194-19
FIG C