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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
only one side return air is used.
Not all horizontal furnaces are approved for side return air
connections (See Fig. 20.)
Step 4—Filter Arrangement
Never operate a furnace without a filter or with filter access
door removed. Failure to follow this warning could result in
fire, personal injury, or death.
There are no provisions for an internal filter rack in these furnaces.
An external filter rack is required.
This furnace is shipped with a factory-supplied Media Filter
Cabinet. The Media Filter Cabinet uses either a factory-supplied
standard 1-inch filter or 4-inch wide Media Filter which can be
purchased separately.
Refer to the instructions supplied with Media Cabinet for assembly
and installation options.
Step 5—Air Ducts
GENERAL REQUIREMENTS
The duct system should be designed and sized according to
accepted national standards such as those published by: Air
Conditioning Contractors Association (ACCA), Sheet Metal and
Air Conditioning Contractors National Association (SMACNA) or
American Society of Heating, Refrigerating and Air Conditioning
Engineers (ASHRAE) or consult The Air Systems Design Guide-
lines reference tables available from your local distributor. The
duct system should be sized to handle the required system design
CFM at the design external static pressure.
When a furnace is installed so that the supply ducts carry air to
areas outside the space containing the furnace, the return air must
also be handled by a duct(s) sealed to the furnace casing and
terminating outside the space containing the furnace.
Secure ductwork with proper fasteners for type of ductwork used.
Seal supply- and return-duct connections to furnace with code
approved tape or duct sealer.
Installation tip: Flexible connections should be used between
ductwork and furnace to prevent transmission of vibration.
Ductwork passing through unconditioned space should be insu-
lated to enhance system performance. When air conditioning is
used, a vapor barrier is recommended.
Table 3—Opening Dimensions (In.)
FURNACE
CASING
WIDTH
APPLICATION
PLENUM OPENING
FLOOR OPENING
A
B
C
D
14–3/16
Upflow Applications on Combustible or Noncombustible
Flooring (KGASB subbase not required)
12-11/16
21-5/8
13-5/16
22-1/4
Downflow Applications on Noncombustible Flooring
(KGASB subbase not required)
12-9/16
19
13-3/16
19-5/8
Downflow applications on combustible flooring (KGASB
subbase required)
11-13/16
19
13-7/16
20-5/8
Downflow Applications on Combustible Flooring with CD5 or
CK5 Coil Assembly or KCAKC coil box (KGASB subbase
not required)
12-5/16
19
13-5/16
20
17–1/2
Upflow Applications on Combustible or Noncombustible
Flooring (KGASB subbase not required)
16
21-5/8
16-5/8
22-1/4
Downflow Applications on Noncombustible Flooring
(KGASB subbase not required)
15-7/8
19
16-1/2
19-5/8
Downflow applications on combustible flooring (KGASB
subbase required)
15-1/8
19
16-3/4
20-5/8
Downflow Applications on Combustible Flooring with CD5 or
CK5 Coil Assembly or KCAKC coil box (KGASB subbase
not required)
15-1/2
19
16-1/2
20
21
Upflow Applications on Combustible or Noncombustible
Flooring (KGASB subbase not required)
19-1/2
21-5/8
20-1/8
22-1/4
Downflow Applications on Noncombustible Flooring
(KGASB subbase not required)
19-3/8
19
20
19-5/8
Downflow applications on combustible flooring (KGASB
subbase required)
18-5/8
19
20-1/4
20-5/8
Downflow Applications on Combustible Flooring with CD5 or
CK5 Coil Assembly or KCAKC coil box (KGASB subbase
not required)
19
19
20
20
24-1/2
Upflow Applications on Combustible or Noncombustible
Flooring (KGASB subbase not required)
23
21-1/8
23-5/8
22-1/4
Downflow Applications on Noncombustible Flooring
(KGASB subbase not required)
22-7/8
19
23-1/2
19-5/8
Downflow applications on Combustible flooring (KGASB
subbase required)
22-1/8
19
23-3/4
20-5/8
Downflow Applications on Combustible Flooring with CD5 or
CK5 Coil Assembly or KCAKC coil box (KGASB subbase
not required)
22-1/2
19
23-1/2
20
11
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