507714-01
Page 10 of 52
Issue 1716
Figure 13.
NOTE:
These units may be equipped with a shipping pad
under the blower housing. Remove the shipping pad prior
to operation.
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or
alcove installations are shown in Figure 14.
Blower access panel must be securely in place when
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
The unit may be installed three ways in downflow
applications: on non-combustible flooring, on combustible
flooring using an additive base, or on a reverse-flow
cooling coil cabinet. Do not drag the unit across the floor
in the downflow position. Floor and furnace flange damage
will result.
Refer to Figure 14 for clearances in downflow applications.
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
air in the living space. Use sheet metal screws and joint
tape to seal return air system to furnace.
In platform installations with furnace return, 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.
For no reason should return and supply air duct systems
ever 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
Figure 14.
Downflow Application Installation
Clearances
Top
0
* Front
0
Back
0
Sides
0†
Vent
0
Floor
NC‡
* Front clearance in alcove installation must be 24 in. (610
mm). Maintain a minimum of 24 in. (610 mm) for front service
access.
† Allow proper clearances to accommodate condensate trap.
‡ The furnace may be installed on a combustible wood floor if
an optional additive base is installed between the furnace and
the combustible floor.
Installation on Non-Combustible Flooring
1. Cut floor opening keeping in mind clearances listed
on unit rating plate. Also keep in mind gas supply
connections, electrical supply, flue and air intake
connections and sufficient installation and servicing
clearances. See Table 1 for correct floor opening size.
2. Flange warm air plenum and lower the plenum into the
opening.
3. Set the unit over the plenum and seal the plenum to
the unit.
4. Ensure that the seal is adequate.
Table 1. Non-Combustible Floor Opening Size
Cabinet
Width
Front to Rear
Side to Side
in.
mm
in.
mm
B cabinet
(17.5”)
19-3/4
502
16-5/8
422
C cabinet
(21”)
19-3/4
502
20-1/8
511
NOTE
: Floor opening dimensions listed are 1/4 in. (6 mm)
