Downflow Furnaces; Installation On A Concrete Slab - Heat Controller 80+ AFUE Installation Instructions Manual

Downflow Installation
The furnace must not be installed directly on carpeting,
tile, or any combustible material other than wood
flooring. To install the furnace on combustible flooring,
a special sub-base is required.
wARNING:
Failure to install the downflow sub-base kit may
result in fire,property damage or personal injury.
wARNING:
The downflow sub-base kit must not be installed
directly on carpeting, tile, or any combustible
material other than wood flooring. Failure to
comply may result in fire, property damage or
personal injury.
Downflow sub-base kits are factory supplied accessories
and are listed according to the cabinet letter of the furnace.
For 'A' size cabinets use Sub-Base kit #902974 only. For
'B', 'C', and 'D' size cabinets use Kit #904911. please
follow the instructions provided with the kit.
A downflow sub-base kit is not necessary if the furnace
is installed on a factory or site-built cased air conditioning
coil. However, the plenum attached to the coil casing
must be installed so that its surfaces are at least 1" from
combustible construction.

Installation on a Concrete Slab

1. Create an opening in the floor according to the
dimensions in Table 1.
2. Position the plenum and the furnace as shown in
Figure 9.
14
Threaded
Rod
Figure 8. GUH80A Horizontally Suspended in Attic
Concrete
Furnace
Floor
Plenum
Figure 9. Furnace on a Concrete Slab
Opening in concrete floor
"B"
GDD80A
Dim. "A"
Models
054A3XE
072B4XE
090B4XE
108C5XE
126D5XE
NOTE: Dimensions shown in Inches.
Table 1. Cutout Dimensions
Nuts (x2)
Lag
Bolt
Washer
and
Lockwasher
Nuts (x2)
Sheet
Metal
"A"
Dim. "B"
13 1/4 19 1/4
16 5/8 19 1/4
16 5/8 19 1/4
20 1/8 19 1/4
23 5/8 19 1/4