507651-01
Issue 1907
Page 11 of 32
Filters
This unit is not equipped with a filter or rack. A field provided
high velocity filter is required for the unit to operate properly.
Table 1 lists recommended filter sizes.
If a high-efficiency filter is being installed as part of this
system to ensure better indoor air quality, the filter must
be properly sized. High-efficiency filters have a higher
static pressure drop than standard-efficiency glass/foam
filters. If the pressure drop is too great, system capacity
and performance may be reduced. The pressure drop
may also cause the limit to trip more frequently during
the winter and the indoor coil to freeze in the summer,
resulting in an increase in the number of service calls.
Before using any filter with this system, check the
specifications provided by the filter manufacturer
against the data given in the appropriate Product
Specifications. Additional information is provided in
Service and Application Note ACC002 (August 2000).
IMPORTANT
A filter must be in place any time the unit is operating.
Table 1.
Furnace Cabinet
Width
Filter Size
Side Return
Bottom Return
14-1/2”
16 x 25 x 1 (1)
14 x 25 x 1 (1)
17-1/2”
16 x 25 x 1 (1)
21”
20 x 25 x 1 (1)
If this unit is being installed in a space serviced by an
exhaust fan, power exhaust fan, or other device which
may create a negative pressure in the space, take care
when sizing the inlet air opening. The inlet air opening
must be sized to accommodate the maximum volume
of exhausted air as well as the maximum volume of
combustion air required for all gas appliances serviced
by this space.
CAUTION
Improper installation of the furnace can result in
personal injury or death. Combustion and flue products
must never be allowed to enter the return air system or
the living space. Use screws and joint tape to seal the
return air system to the furnace.
In platform installations with bottom return air, the furnace
should be sealed airtight to the return air plenum. A door
must never be used as a portion of the return air duct
system. The base must provide a stable support and an
airtight seal to the furnace. Allow absolutely no sagging,
cracks, gaps, etc..
The return and supply air duct systems must never be
connected to or from other heating devices such as a
fireplace or stove, etc. Fire, explosion, carbon monoxide
poisoning, personal injury and/or property damage
could result.
WARNING
The inner blower panel must be securely in place when
the blower and burners are operating. Gas fumes,
which could contain carbon monoxide, can be drawn
into living space resulting in personal injury or death.
WARNING
Duct System
Use industry approved standards (such as those published
by Air Conditioning Contractors of America or American
Society of Heating, Refrigerating and Air Conditioning
Engineers) to size and install the supply and return air duct
system. This will result in a quiet and low static system that
has uniform air distribution.
NOTE:
Do not operate the furnace in the heating mode
with an external static pressure that exceeds 0.8 inches
w.c. Higher external static pressures may cause erratic
limit operation.
