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can be hung from floor joists, rafters or trusses or installed on a
non- -combustible platform, blocks, bricks or pad.
Suspended Furnace Support
The furnace may be supported under each end with threaded rod,
angle iron or metal plumber's strap as shown. (See Fig. 15 and
16.) Secure angle iron to bottom of furnace as shown.
Heavy- -gauge sheet metal straps (plumber's straps) may be used
to suspend the furnace from each bottom corner. To prevent
screws from pulling out, use 2 #8 x 3/4 in. screws into the side
and 2 #8 x in. screws in the bottom of the furnace casing for each
strap. (See Fig. 15 and 16.)
If the screws are attached to ONLY the furnace sides and not the
bottom, the straps must be vertical against the furnace sides and
not pull away from the furnace sides, so that the strap attachment
screws are not in tension (are loaded in shear) for reliable support.
Platform Furnace Support
Construct working platform at location where all required furnace
clearances are met. (See Fig. 2 and 17.) For furnaces with 1- -in.
(25 mm) clearance requirement on side, set furnace on
non- -combustible blocks, bricks or angle iron. For crawlspace
installations, if the furnace is not suspended from the floor joists,
the ground underneath furnace must be level and the furnace set
on blocks or bricks.
A
PLENUM
OPENING
B
C
Fig. 11 - - Floor and Plenum Opening Dimensions
Roll- -Out Protection
Provide a minimum 17- -3/4- -in. X 22- -in. (451 X 559 mm) piece
of sheet metal for flame roll- -out protection in front of burner area
for furnaces closer than 12- -in. (305 mm) above the combustible
deck or suspended furnaces closer than 12- -in. (305 mm) to joists.
The sheet metal MUST extend underneath the furnace casing by
1- -in. (25 mm)with the door removed.
The bottom closure panel on furnaces of widths 17- -1/2- -in. (445
mm) and larger may be used for flame roll- -out protection when
bottom of furnace is used for return air connection. See Fig. 17
for proper orientation of roll- -out shield.
Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return- -air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel,
perform the following:
1. Tilt or raise furnace and remove two screws holding bot-
tom filler panel. (See Fig. 9.)
D
FLOOR
OPENING
A96283
2. Rotate bottom filler panel downward to release holding
tabs.
3. Remove bottom closure panel.
4. Reinstall bottom filler panel and screws.
Side Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return- -air opening. This panel MUST be in place when
side return air inlet(s) are used without a bottom return air inlet.
Not all horizontal furnaces are approved for side return air
connections (See Fig. 20.)
(OR COIL CASING
WHEN USED)
COMBUSTIBLE
DOWNFLOW
SHEET METAL
Fig. 12 - - Furnace, Plenum, and Subbase Installed on a
Combustible Floor
FURNACE
APPROVED
COIL ASSEMBLY
COIL BOX
COMBUSTIBLE
FLOORING
SHEET METAL
PLENUM
OPENING
Fig. 13 - - Furnace, Plenum, and Coil Assembly or Coil Box
Installed on a Combustible Floor
11
FURNACE
FLOORING
SUBBASE
PLENUM
FLOOR
OPENING
OR
FLOOR
A96285
A08556
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