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To install the furnace on combustible fl ooring, a special
sub-base is required. Downfl ow 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 downfl ow 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.
*SC series furnaces are shipped with the bottom panel
installed. If the furnace is installed horizontally, remove
the bottom panel from the furnace before attaching the
duct system. See Bottom Panel Removal.
If the furnace is to be suspended from the ceiling, it will
be necessary to use steel straps around each end of the
furnace. The straps should be attached to the furnace with
sheet metal screws and to the rafters with bolts. The furnace
could also be suspended by an angle iron frame bolted to
the rafters (Figure 8, page 9). Access for positioning and
servicing must be considered when locating the unit. See
Table 3 (page 27) for clearance specifi cations.
If the furnace is to be installed in an attic, it is required that
a drip pan be placed under the furnace. If the installation is
on a combustible platform (Figure 14), it is recommended
that the drip pan extend at least 12 inches past the top
and front of the furnace.
Bottom Panel Removal
To remove the bottom panel (Figure 15) from the upfl ow
furnace, perform the following steps:
1. Remove the blower door (1) from bottom of furnace.
2. Disconnect the wiring harness (2) from the
connector.
3. Remove two screws (3) securing the blower assembly
(4) to the furnace.
4. Carefully pull the blower assembly (4) out thru the
front of the furnace.
5. Remove all screws (5) securing bottom panel (6) to
bottom of furnace and front brace (7).
6. Lift up and slide bottom panel (6) out through front of
furnace.
7. Reinstall the blower assembly (4) in reverse order it
was removed.
Downfl ow Installation
WARNING:
The furnace must not be installed directly on
carpeting, tile, or any combustible material other
than wood fl ooring.
The *SL series gas furnace is certifi ed for installation on
combustible fl ooring.
This furnace must not be installed
directly on carpeting, tile, or any combustible material
other than wood fl ooring.
For venting guidelines and
specifi cations, see Venting Requirements on page 11.
WARNING:
Failure to install the downfl ow sub-base kit
may result in fi re, property damage or personal
injury.
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5
Figure 15. Removal of Bottom Panel
Blower Assembly
Bottom Panel
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3
3
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