035-17468-001 Rev. A (801)
8
Unitary Products Group
4.
Install the filter(s) provided. Cut filter if necessary to
match air opening in cabinet. Filter should extend
beyond opening edge as much as possible to prevent air
from bypassing the filter. DO NOT remove stiffening rods
from inside the filter. Shorten the rods, if necessary, to
match final filter size.
5.
Position the filter between the wire retainer and the cabi-
net wall (or floor) so it completely covers the cabinet air
opening and secure the filter in place at the front of the
cabinet by fastening the closed (looped) end of the
retainer wire under the flanged edge of the cabinet.
When properly installed the filter should fit flush with all
four sides of the cabinet wall.
NOTE:
Air velocity through throw-away type filters may not
exceed 300 feet per minute. All velocities over this require the
use of high velocity filters.
Side Return - External Filter
Locate and knock out the square corner locators. These indi-
cate the size of the cutout to be made in the furnace side
panel, See Figure 5.
Install the side filter rack following the instructions provided
with that accessory. If a filter(s) is provided at another loca-
tion in the return air system, the ductwork may be directly
attached to the furnace side panel.
NOTE:
Some accessories such as electronic air cleaners and
pleated media may require a larger side opening. Follow the
instructions supplied with the accessory for side opening
requirements.
The return duct may be attached to the furnace by S-cleat,
bend tabs or other approved methods. Be sure to seal the
duct to the furnace to prevent air leakage.
Where the return duct system is not complete, the return con-
nection must run full size to a location outside the utility room
or basement. For further details, consult Section 5.3 (Air for
Combustion and Ventilation) of the National Fuel Gas Code,
ANSI Z223.1, or CAN/CGA B149.1 or.2, Installation Code -
latest editions.
Bottom Return
Bottom return applications normally pull return air through a
base platform or return air plenum. Be sure the return plat-
form structure is suitable to support the weight of the furnace.
Be sure to seal the furnace to plenum connection to prevent
air leakage.
The bottom panel is equipped with a perforated opening for
easy removal. Tabs must be cut with sheet metal snips to
allow removing knock-out. Scribe marks are included for
forming flanges for attachment of the return air ductwork.
NOTE:
If an external mounted filter rack is being used, see
the instructions provided with that accessory for proper hole
cut size.
Upflow attic installations must meet all minimum clearances
to combustibles and have floor support with required service
accessibility.
DOWNFLOW/HORIZONTAL MODELS
COOLING COIL TRANSITION
These furnace models are equipped with perforations in the
supply air wrapper flanges that allow for easy application of
air conditioning coil to the furnace without the use of sheet
metal transition pieces, These perforations can be bent in
either direction depending on the type of application - either
downflow or horizontal left and right. Refer to either the
“Downflow Application” or “Horizontal Application” section
below for specific instructions on how to install the coil.
Downflow Installations
For installation of air conditioning coil in a downflow applica-
tion, the perforations in the wrapper flanges must be bent in
towards the heat exchanger to allow for the coil duct flange to
recess into the furnace. Refer to the installation instructions
supplied with the air conditioning coil for additional informa-
tion and completion of the coil installation.
NOTE:
Duct pliers or other suitable tool can be used to bend
perforations. To help bend flanges in a straight line, scribe a
line between the perforations prior to bending.
FIGURE 4 :
Side Filter Retainer Placement
FIGURE 5 :
Side Return Cutout Markings
FILTER
PROVIDED
POSITION WIRE RETAINER
PROVIDED UNDER FLANGE
CLIPS
RIGHT SIDE
INSTALLATION
SHOWN
FURNACE
FRONT
CORNER
MARKINGS
FRONT OF
FURNACE
All installations must have a filter installed.
