10
PRODUCT DESIGN
Counterflow Filters"A"
Min
Return Air
Optional
Access
Door
This furnace has provisions for the installation of return air filters at the counterflow top return. The furnace will accommodate
the following 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
(in2)Qty Filter Size
(in) Dimension "A"
(in)
21 13.0
24 1/2 11.3
21 18.8
24 1/2 17.7
21 24.3
24 1/2 23.4
15 X 20 X 1
20 X 20 X 1
25 X 20 X 1
600
800
1000
2
2
2
Counterflow Top Return