Jack BIG BJ90 Owner's Manual - page 12
12
COMBUSTION AIR
Make-up outside air to the furnace for proper fuel combustion must
be provided by openings to the outside of the building. The open-
ings of ducts supplying such make-up air shall have unobstructed
areas not less than the area of the flue furnace pipe.
NOTE
Outside air is needed to replace the air used by the burner and
wood combustion process. Outside air is also required to
replace the air used for taking the by-products of combustion
of the gas or oil burner and wood/coal smoke out the chimney.
Outside air is also needed to replace any air expelled by
kitchen or bathroom fans as well as water heater chimneys or
fans.
Failure to provide outside air to the area in which the furnace
is located will result in a negative pressure or vacuum in the
home. Smoke from the wood fire may not be drawn up the
chimney, causing creosote buildup and sometimes causing
smoke to enter the furnace room.
WARNING
You must provide for enough fresh air to assure proper com-
bustion. The fire in the furnace uses oxygen and must have a
continuous supply. The air in a house contains only enough
oxygen to supply the furnace for a short time. Outside air must
enter the house to replace that used by the burner.