25
Table 6 – Filter Media Pressure Drop (Clean) Versus Face Velocity
−
In. W.C. (Pa)
Face Velocity
FactoryAccessory
Washable
Representative AfterMarket Filter Media*
Fiberglass*
Pleated*
FPM
(m/s)
(1in. / 2.5 cm)
(1in. / 2.5 cm)
(2in. / 5 cm)
(1in. / 2.5 cm)
(2in. / 5 cm)
200
(1)
0.04
(10)
0.05
(13)
0.08
(20)
0.18
(47)
0.12
(31)
300
(1.5)
0.05
(14)
0.09
(22)
0.13
(34)
0.30
(75)
0.21
(52)
400
(2)
0.07
(17)
0.13
(32)
0.20
(50)
0.31
(78)
500
(2.5)
0.08
(21)
0.18
(44)
0.27
(69)
600
(3)
0.09
(23)
0.23
700
(3.6)
0.10
(26)
0.29
Table 7 – Air Filter Selection and Duct Sizing
−
In. (mm)
FURNACE CASING WIDTH
FILTER SIZE
FILTER TYPE
SIDE
RETURN
BOTTOM
RETURN
14-3/16
(360)
16 x 25 x 3/4
(406 x 635 x 19)
14 x 25 x 3/4
(356 x 635 x 19)
Washable*
17-1/2 (445)
16 x 25 x 3/4
(406 x 635 x 19)
16 x 25 x 3/4
(406 x 635 x 19)
Washable*
21 (533)
16 x 25 x 3/4
(406 x 635 x 19)
20 x 25 x 3/4
(508 x 635 x 19)
Washable*
24-1/2 (622)
16 x 25 x 3/4
(406 x 635 x 19)
24 x 25 x 3/4
(610 x 635 x 19)
Washable*
* Recommended to maintain air filter face velocity. See Product Data for part number.
Not all families have these models.
TABS
FILTER
FRAME
FILTER
(FIELD SUPPLIED)
DOOR
FURNACE
OPENING
TABS
(TYP.)
3
4”
/
OPENING
14
1
2”
/
16
1
8”
/
2
3
8”
/
1
2”
/
3
8”
/
1
1
4”
/
1
1
4”
/
25
1
8”
/
17
1
8”
/
23
1
8”
/
(32 mm)
(10 mm)
(13 mm)
(60 mm)
(19 mm)
(410 mm)
(368 mm)
(587 mm)
(435 mm)
(32 mm)
(638 mm)
A11091
Fig. 19
−
Accessory Side Filter Rack
A11095
Fig. 20
−
Accessory Bottom Filter
912S