Crown Boiler AWR Series Installation Instructions Manual page 12

FIGURE 5.2: ALL AIR FROM OUTDOORS, VENTILATED CRAWL SPACE AND ATTIC
FIGURE 5.3: ALL AIR FROM OUTDOORS, VIA VENTILATED ATTIC
1) Openings must be installed between the boiler room and the outdoors or a ventilated space, such as an attic or crawl
space, which communicates directly with the outdoors.
2) Two openings are required. The top edge of the upper opening must be within 6 inches of the ceiling. The bottom edge
of the lower opening must be within 6 inches of the floor.
3) Size openings and ducts as follows:
•
Vertical ducts or openings directly outdoors (Figure 5.2, Figure 5.3, and Figure 5.4) - Each opening must have a free
cross sectional area of 1 square inch per 4000 BTU/hr of the total input of all gas-fired appliances in the boiler room.
Minimum opening size is 3 inches.
•
Openings to outdoors via horizontal ducts (Figure 5.5) - Each opening must have a free cross sectional area of 1
square inch per 2000 BTU/hr of the total input of all gas fired appliances in the boiler room. Minimum opening size
is 3 inches.
6"
Using the Outdoor Combustion Air Method
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