035-17477-002 Rev. D (1202)
10
Unitary Products Group
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 must enter through the
end only.
Return air may not be connected into the rear or
side panels 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). Refer to furnace accessories
on Page 31 for external filter kit options.
ATTIC INSTALLATION
FIGURE 6 :
downflow filters
FIGURE 7 :
Combustible Floor Base Accessory
NOTE: FILTER ACCESS THRU DUCT-
WORK MUST BE PROVIDED FOR
REMOVAL AND CLEANING
BRANCH
DUCTS
CROSS SECTION A-A
(WITH PLENUM AND FILTERS)
DUCTWORK
FILTERS
FILTER
RACK
FH
RACK AND FILTERS SECURED
INSIDE BLOWER SECTION
FOR SHIPMENT
FILTER RACK
(FACTORY SUPPLIED)
CASING SIZE
DIMENSION FH
16-1/4
12-3/4
22-1/4
11
26-1/4
8-1/4
A
A
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
RETURN AIR
SEDIMENT
TRAP
GAS PIPING
SUPPLY AIR
VENT (Maintain
required clearances
to combustibles)
SHEET METAL
IN FRONT OF
FURNACE
COMBUSTION AIR
OPENINGS IS
RECOMMENDED
LINE CONTACT ONLY PERMISSIBLE
BETWEEN LINES FORMED BY THE
INTERSECTION OF FURNACE TOP
AND TWO SIDES AND BUILDING
JOISTS, STUDS OR FRAMING
12”
30” MIN.
WORK AREA
