13
PRODUCT DESIGN
Counterflow Filters
"A"
Min
Return Air
Optional
Access
Door
Return air filters may be installated at the at the counterflow top return. A field supplied center filter support must be provided
by the installer in order to use the top return. The furnace will accommodate the following counterflow top return filter sizes
depending on cabinet size:
Refer to Minimum Filter Area tables to determine filter area requirement.
NOTE:
Filters can also be installed elsewhere
in the duct system such as a central return.
Cabinet Width
Filter Area
(in
2
)
Qty
Filter Size
(in)
Dimension "A"
(in)
17 1/2
14.2
21
13.0
24 1/2
11.3
17 1/2
19.7
21
18.8
24 1/2
17.7
17 1/2
25.0
21
24.3
24 1/2
23.4
800
2
20 X 20 X 1
1000
2
25 X 20 X 1
Counterflow Top Return
600
2
15 X 20 X 1
