507713-01
Page 11 of 32
Issue 1623
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.
A filter must be in place any time the unit is operating.
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.
Supply Air Plenum
If the furnace is installed without a cooling coil, a removable
access panel must be installed in the supply air duct. The
access panel should be large enough to permit inspection
(either by smoke or reflected light) of the heat exchanger
for leaks after the furnace is installed. The furnace access
panel must always be in place when the furnace is operating
and it must not allow leaks into the supply air duct system.
Return Air Plenum
NOTE:
Return air must not be drawn from a room where
this furnace, or any other gas fueled appliance (i.e., water
heater), or carbon monoxide producing device (i.e., wood
fireplace) is installed.
When return air is drawn from a room, a negative pressure
is created in the room. If a gas appliance is operating in a
room with negative pressure, the flue products can be pulled
back down the vent pipe and into the room. This reverse
flow of the flue gas may result in incomplete combustion and
the formation of carbon monoxide gas. This toxic gas might
then be distributed throughout the house by the furnace
duct system.
In upflow applications, the return air can be brought in
through the bottom or either side of the furnace. If a furnace
with bottom return air is installed on a platform, make an
airtight seal between the bottom of the furnace and the
platform to ensure that the unit operates properly and safely.
Use fiberglass sealing strips, caulking, or equivalent sealing
method between the plenum and the furnace cabinet to
ensure a tight seal. If a filter is installed, size the return air
duct to fit the filter frame.
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
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.
Table 1
Figure 14
Horizontal Application
Unit installed on Platform
