AERCO Esteem O&M Manual - Manual (Page 16)

10
Ventilation and Combustion Air Requirements - Category IV
• 1 sq. in./3000 Btu/hr of the total input
rating of all equipment located in the
enclosures, and
• Not less than the sum of the areas of all
vent connectors in the space.
Two Permanent Openings Method.
Two permanent openings, one commencing
within 12 inches of the top and one commenc-
ing within 12 inches of the bottom of the enclo-
sure, shall be provided. The openings shall
communicate directly, or by ducts, with the
outdoors or spaces that freely communicate
with the outdoors, as follows:
• Where directly communicating with the
outdoors or where communication to the
outdoors is through vertical ducts, each
opening shall have a minimum free area of
1 sq. in./4000 Btu/hr of total input rating for
all equipment in the enclosure.
See Figure 4.
• Where communicating with the outdoors
is through horizontal ducts, each opening
shall have a minimum free area of not less
than 1 sq. in./2000 Btu/hr of total input rat-
ing of all equipment in the enclosure. See
Figure 5.
Figure 3: :
All Combustion Air from Outdoors Through One
Permanent Air Opening Figure 4: :
All Combustion Air from Outdoors Through
Ventilated Attic
Figure 5: :
All Combustion Air from Outdoors through
Horizontal Ducts
GF-125