28
Table 6 – Filter Media Pressure Drop (Clean) Versus Face Velocity-- In. W.C. (Pa)
Face Velocity
Factory-Accessory
Washable
Representative After-Market Filter Media*
Fiberglass*
Pleated*
FPM
(m/s)
(1-in. / 2.5 cm)
(1-in. / 2.5 cm)
(2-in. / 5 cm)
(1-in. / 2.5 cm)
(2-in. / 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
-
-
-
-
-
-
-
* Representative estimates from filter manufacturer data sheets.
See manufacturers’ specifications for pressure drop versus airflow data for specific filter media..
See Table 7 for filter size details.
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.
Air Filter Located in Filter Cabinet
FILTER CABINET HEIGHT --- IN (MM)
FILTER SIZE --- IN (MM)
FILTER TYPE
16 (406)
(1) 16 x 25 x 3/4*
(406 x 635 x 19) or
(1) 16 x 25 x 4---5/16
(406 x 635 x 110)
Washable or Media*
20 (508)
(1) 20 x 25 x 3/4*
(508 x 635 x 19) or
(1) 20 x 25 x 4---5/16
(508 x 635 x 110)
Washable or Media*
24 (610)
(1) 24 x 25 x 3/4*or
(610 x 635 x 19) or
(1) 24 x 25 x 4---5/16
(610 x 635 x 110)
Washable or Media*
* Filters with a side return---air may have a different filter size. Measure the filter to obtain the correct size.
* Recommended to maintain air filter face velocity. See Product Data for part number.
