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MFC Series Boiler Vent and Combustion Air Guide
TAG-0080_OG
•
GF-148-V
•
3/29/2023
Technical Support
•
(800) 526-0288
•
Mon-Fri, 8 am - 5 pm EST Page 8 of
33
Figure 4: All Combustion Air from Outdoors - Through Ventilated Attic
•
When communicating with the outdoors through horizontal ducts, each opening shall have a
minimum free area of 1 inch
2
per 2,000 BTU/hr. (1100 mm
2
/kW) of total input rating of all
appliances in the space (see Figure 5).
Figure 5: All Combustion Air from Outdoors through Horizontal Ducts
OUTDOOR OPENINGS
TO HORIZONAL AIR
DUCTS