Procom PC32VFC Manual page 8

Ventilation Air from Inside Building
This fresh air would come from adjoining
unconfined space. When ventilating to an
adjoining unconfined space, you must
provide two permanent openings: one
within 12 inches of the wall connecting
the two spaces (see options 1 and 2,
Figure 2). You can also remove door into
adjoining room (see option 3, Figure 2).
Follow the National Fuel Gas Code NFPA
54/ANSI Z223.1. Air for Combustion and
Ventilation for required size of ventilation
grills or ducts.
Ventilation Air from Outdoors
Provide extra fresh air by using ventilation
grills or duct. You must provide two
permanent openings: one within 12 inches
of the ceiling and one within 12 inches of
the floor. Connect these items directly to
the outdoors or spaces open to the outdoors.
These spaces include attics and crawl spaces.
Follow the National Fuel Gas Code NFPA
54/ANSI Z223.1. Air for Combustion and
Ventilation for required size of ventilation grills or ducts.
IMPORTANT: Do not provide openings for
inlet or outlet air into attic if attic has a
thermostat-controlled power vent. Heated
air entering the attic will activate the
power vent. Rework worksheet, adding the
space of the adjoining unconfined space. The
combined spaces must have enough fresh air to
supply all appliances in both spaces.
Figure 2 - Ventilation Air from Inside Building
Figure 3 - Ventilation Air from Outdoors
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