Installation guide

Exploded View of Sub-Base for
Furnace ONLY
Plenum
S
H
J
Combustible
Floor Base
25-21-46b
Setting the Base
Subbase
Insulation
Wood Floor
Plenum
25-20-46A
Exploded View of Base for
Downflow Cased Coil
Plenum
Combustible
Floor Base
25-21-46b
Consideration must be given to the height of the base to allow for
easy installation of the condensate drain. See Figure 17. This
subbase for combustible floors has been designed so that the
height of the subbase ra ises the downflow coil off the floor to allow
easy installation of the condensate drain
Setting the Base
co,
Subbase
Insulation /
Wood Screw _ _ _ Plenum 25-20-46A
Sub-base for Combustible Floors- Downflow Coil
Adapter Box
The subbase for combustible floors is required when a downflow
furnace, used with a downflowcoilbox, is set on combustible
flooring.
7
NOTE: Supply opening is 3 /8' from the rear of the furnace. There-
fore maintain a 37/8 " clearance from wall (where applicable).
1,
2,
3.
Cut the opening in the floor according to the dimensions in
Table 4 because the base is equipped with locating tabs that
center the base over the opening.
The opening in the base is 11/4" shorter and 11/8" narrower
than the minimum required size of the opening in the floor. This
is done to maintain a 1" clearance between the floor and the
plenum.
Fabricate the plenum to the dimensions in Table 4. Note that
the dimensions given are outside dimensions.
Set the base over the opening in the floor, centering the open-
ing in the base over the opening in the floor. Fasten the base to
the floor with screws or nails. See Figure 15 and Figure 16.
4.
441 01 231402
Drop the plenum through the opening in the base. The flange
of the plenum should rest on top of the combustible floor base.
Condensate Line Raised by Base
25-20-52
Non-Combustible Floor:
Set the furnace over the opening in the floor. If necessary, grout
around the base to seal air leaks between the base and the floor.
Filters:
A filter MUST be used.
The 181/4" X 1 53/4" framed high-velocity filters supplied with the
furnace may be installed in the return air plenum above the fur-
nace. A filter rack is supplied with each furnace. See Figure 18.
Use either filter type:
• Washable, high-velocity filters are based on a maximum air
flow rating of 600 FPM.