8
INSTALLATION #3
The baffle on this system should be made the full width of the furnace
plenum in order to properly direct the air into the distribution ducts.
INSTALLATION #2
Extending the hot air duct from the furnace into the existing plenum
will help direct the flow of air from the furnace as well as the flow in
the existing furnace. Ducting entering the existing plenum at an angle
(approximately 45 degrees) will facilitate air flow from the furnace while
diverting air from the existing furnace.
THE PLENUM OPENINGS DIFFER
BETWEEN THE 1602 AND 1802
MODEL 1602 -
13” x 18” Rectangular
MODEL 1802 -
18” x 18” Rectangular
RETURN AIR IS VERY IMPORTANT
When installing your furnace, return air MUST BE incorporated into
the system. Return air can be provided by installing a separate duct
system or by tying into the cold air return of an existing gas or oil
furnace. The cold air return duct can be connected to the furnace with
either a factory manufactured filter box, model UFB908 or an equiva
-
lent fabricated from sheet metal.
When installing a cold air return, the minimum size shall be a 16” x
20” or equivalent (320 sq. in.) in order to insure proper furnace per
-
formance. Failure to provide return air ducts of the specified size will
void your warranty.
A filter should be installed in the cold air return. Furnace filters should
be checked and cleaned/replaced regularly.
If return air is not provided, the warm air distributed into your home
will be restricted and the efficiency of the furnace is decreased. With
-
out a return air system, warm air will be drawn into your basement,
unnecessarily heating unused areas of the home. In extreme cases, if
your basement or utility room is fairly airtight, the blowers on the fur
-
nace could depressurize the room and pull toxic flue gases from the
furnace, a gas water heater, or gas furnace. The fumes could then be
distributed throughout the house.
COMBUSTION AIR
All fires need air (specifically oxygen) to burn. Furnaces, fireplaces,
and wood burning furnaces need enough oxygen for complete com
-
bustion of their fuels. The incomplete combustion that takes place
when a furnace is “air starved” causes carbon monoxide (CO) to be
formed in quantities that can be dangerous inside a well sealed house.
Having a source of combustion air from outside the home will prevent
“air starvation” of the furnace. A simple positive air supply can be con
-
structed using dryer vent and a modified termination.
NEGATIVE
PRESSURE IN
BASEMENT
PLENUM OPENING
13” x 18” Rectangular
Summary of Contents for SF747
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