Step 4—Horizontal Attic Installation
Do not install the furnace on its back; safety control operation
will be adversely affected. Never connect return-air ducts to
the sides or back of the furnace. Failure to follow this warning
could result in fire, personal injury, or death.
The furnace can be installed horizontally on either the left-hand
(LH) or right-hand (RH) side. A typical attic installation is shown
in Fig. 7.
CONSTRUCT A WORKING PLATFORM
Construct working platform on location where all required
furnace clearances are met. (See Table 1 and Fig. 7.)
INSTALL FURNACE
1. Position furnace in desired location.
2. Connect gas supply pipe. See Fig. 7 for typical piping entry.
3. Install field-supplied filter retainers as indicated in Fig. 8 and
Table 4 before connecting return-air duct to furnace.
4. Connect supply- and return-air ducts.
5. Install 24- X 24-in. sheet metal shield on platform in front of
louvered control panel as shown in Fig. 7.
Step 5—Horizontal Crawlspace Installation
The furnace can be installed horizontally with either the LH or RH
side up. In a crawlspace, the furnace can either be hung from the
floor joist or installed on suitable blocks or pad. The furnace can
be suspended from each corner by hanger bolts (4 each 3/8-in.
all-thread rod) cut to desired length, 1- X 3/8-in. flat washer,
3/8-in. lockwasher, and 3/8-in. nut. Dimples are provided for hole
locations. (See Fig. 1.)
Since horizontal crawlspace installation is very similar to the attic
installation, refer to Step 4. The installation of a sheet metal shield
in front of the louvered control panel is covered in Step 4. For a
crawlspace installation, this same sheet metal shield must be
installed above the louvered control panel. Extend the sheet metal
shield over the furnace top far enough to cover the gas pipe entry
hole.
Step 6—Filter Arrangement
Never operate unit without a filter or with filter access door
removed. Failure to follow this warning could result in fire,
personal injury, or death.
The 2 factory-supplied filters are shipped in the blower compart-
ment. After the return-air duct has been connected to the furnace,
install the filters in a V-formation inside the return-air plenum. See
Fig. 7—Typical Attic Installation
A82178
30-IN. MIN
WORK AREA
6
″
MIN
FLUE VENT
GAS
ENTRY
24
″
24
″
SHEET
METAL
SEDIMENT TRAP
LINE CONTACT ONLY PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE TOP AND TWO SIDES OF THE FURNACE
JACKET AND BUILDING JOISTS,
STUDS, OR FRAMING.
Fig. 6—Furnace, Plenum, and Subbase Installed on
a Combustible Floor
A78651
DOWNFLOW
SUBBASE
SHEET METAL
PLENUM
FURNACE
(OR COIL CASING
WHEN USED)
6
