035-14370-000
650.75-N4U
Unitary Products Group
11
SUPPLY AIR DUCTS
Installations on combustible material or floors must use a
combustible floor base (shown in Figure 7 - 1CB0314, 17, 21
& 24) as specified on the rating plate or a matching cooling
coil. Follow the instructions supplied with the combustible
floor base accessory.
This base can be replaced with a matching cooling coil, prop-
erly sealed to prevent leaks. Follow the cooling coil instruc-
tions for installing the plenum.
All downflow application supply duct systems must be
designed and installed in accordance with the standards of
NFPA 90A and 90B, and/or all local codes.
DOWNFLOW / HORIZONTAL MODELS -
HORIZONTAL APPLICATION
Downflow furnaces may be installed horizontally with the sup-
ply airflow toward the left or right by laying the unit on the left
or right side panel.
After determining the best orientation, lay the unit on top of
the shipping carton to protect the finish. The appropriate elec-
trical knock-outs for power wiring, control wiring and gas pip-
ing should be removed at this time.
For horizontal application, return air may enter through the
end only. Return air may not be connected into the rear
panel of the unit.
HORIZONTAL FILTERS
All filters and mounting provision must be field supplied. Fil-
ters(s) may be located in the duct system external to the fur-
nace or in a return filter grille(s).
ATTIC INSTALLATION
FIGURE 7 : COMBUSTIBLE FLOOR BASE
ACCESS’Y
DOWNFLOW
FURNACE
WARM AIR PLENUM
WITH 1" FLANGES
FIBERGLASS
INSULATION
FIBERGLASS TAPE
UNDER FLANGE
COMBUSTIBLE FLOOR
BASE ACCESSORY
Do not install the unit on the rear panel.
FIGURE 8 : TYPICAL ATTIC INSTALLATION
VENT (MAINTAIN
REQUIRED CLEARANCES
TO COMBUSTIBLES)
GAS PIPING
SEDIMENT TRAP
12"
30" MIN
WORK AREA
SHEET METAL
IN FRONT OF FURNACE
COMBUSTION
AIR OPENINGS IS
RECOMMENDED
RETURN AIR
SUPPLY AIR
LINE CONTACT ONLY PERMISSIBLE
BETWEEN LINES FORMED BY THE
INTERSECTION OF FURNACE TOP
AND TWO SIDES AND BUILDING
JOISTS, STUDS OR FRAMING
