21
Belt Drive
Dimensional Data
Fan
Size
A
Panel**
B
C
D
E
F*
Damper
Size**
Level 1
Level 1
20
26
(660)
19
1
⁄
2
(495)
16
1
⁄
4
(413)
1
(25)
20
1
⁄
2
(521)
20
(508)
22
(559)
24
32
(813)
19
1
⁄
2
(495)
16
1
⁄
8
(410)
1
1
⁄
4
(32)
24
5
⁄
8
(625)
20
(508)
26
(660)
30
38
(965)
22
1
⁄
2
(572)
18
1
⁄
4
(464)
1
1
⁄
4
(32)
30
5
⁄
8
(778)
21
(533)
32
(813)
36
44
(1118)
21
1
⁄
2
(546)
16
1
⁄
2
(419)
2
(51)
36
5
⁄
8
(930)
23
(584)
38
(965)
42
50
(1270)
25
(635)
20
(508)
2
(51)
42
3
⁄
4
(1086)
23
(584)
44
(1118)
48
56
(1422)
25
(635)
19
(483)
2
(51)
48
3
⁄
4
(1238)
23
(584)
50
(1270)
54
62
(1575)
25
(635)
19
1
⁄
2
(495)
2
(51)
55
1
⁄
4
(1403)
24
(610)
56
(1422)
Level 2
Level 2
20
26
(660)
19
1
⁄
2
(495)
16
1
⁄
4
(413)
1
(
25)
20
1
⁄
2
(521)
20
(508)
22
(559)
24
32
(813)
19
1
⁄
2
(495)
16
1
⁄
8
(410)
1
1
⁄
4
(32)
24
5
⁄
8
(625)
20
(508)
26
(660)
30
38
(965)
21
1
⁄
2
(546)
17
1
⁄
4
(438)
1
1
⁄
4
(32)
30
5
⁄
8
(778)
21
(533)
32
(813)
36
44
(1118)
21
1
⁄
2
(546)
16
1
⁄
2
(419)
2
(51)
36
5
⁄
8
(930)
22
(559)
38
(965)
42
50
(1270)
25
(635)
20
(508)
2
(51)
42
3
⁄
4
(1086)
25
1
⁄
2
(648)
44
(1118)
48
56
(1422)
25
(635)
19
(483)
2
(51)
48
3
⁄
4
(1238)
25
1
⁄
2
(648)
50
(1270)
54
62
(1575)
26
(660)
20
1
⁄
2
(546)
2
(51)
55
1
⁄
4
(1403)
24
(610)
56
(1422)
60
68
(1727)
28
(711)
21
7
⁄
16
(545)
2
(51)
61
1
⁄
4
(1556)
24
(610)
62
(1575)
Level 3 & Reversible
Level 3
24
32
(813)
19
(483)
15
5
⁄
8
(397)
1
1
⁄
4
(32)
24
5
⁄
8
(
625)
20
1
⁄
2
(521)
26
(660)
30
38
(965)
21
1
⁄
2
(546)
17
1
⁄
4
(438)
1
1
⁄
4
(32)
30
5
⁄
8
(778)
20
(508)
32
(813)
36
44
(1118)
28
(711)
23
(584)
2
(51)
36
5
⁄
8
(930)
27
(686)
38
(965)
42
50
(1270)
28
(711)
23
(584)
2
(51)
42
3
⁄
4
(1086)
29
1
⁄
4
(743)
44
(1118)
48
56
(1422)
31
1
⁄
2
(800)
27
1
⁄
2
(699)
2
(51)
48
7
⁄
8
(1238)
30
1
⁄
2
(775)
50
(1270)
54
62
(1575)
35
3
⁄
4
(908)
30
1
⁄
4
(768)
2
(51)
55
1
⁄
4
(1403)
36
1
⁄
4
(921)
56
(1422)
60
68
(1727)
35
(889)
28
7
⁄
16
(722)
2
(51)
61
1
⁄
4
(1556)
35
1
⁄
2
(902)
62
(1575)
72
82
(2083)
35
(889)
28
1
⁄
4
(718)
2
1
⁄
8
(54)
73
1
⁄
4
(1861)
35
1
⁄
2
(902)
74
(1880)
All dimensions given in inches
(mm)
. **Square dimension.
Reversible
A sq.
E
B
C
D
F
D
A sq.
B
C
E
F
D
A sq..
E
B
C
D
Exhaust
Airflow
F
D
Supply
Airflow
D
Exhaust
Airflow
Supply
Airflow
Exhaust
Airflow
Supply
Airflow
A sq.
B
C
E
Exhaust
Airflow
Supply
Airflow
A sq.
E
B
C
D
F
D
A sq.
B
C
E
F
D
A sq..
E
B
C
D
Exhaust
Airflow
F
D
Supply
Airflow
D
Exhaust
Airflow
Supply
Airflow
Exhaust
Airflow
Supply
Airflow
A sq.
B
C
E
Exhaust
Airflow
Supply
Airflow
A sq.
E
B
C
D
F
D
A sq.
B
C
E
F
D
A sq..
E
B
C
D
Exhaust
Airflow
F
D
Supply
Airflow
D
Exhaust
Airflow
Supply
Airflow
Exhaust
Airflow
Supply
Airflow
A sq.
B
C
E
Exhaust
Airflow
Supply
Airflow
A sq.
E
B
C
D
F
D
A sq.
B
C
E
F
D
A sq..
E
B
C
D
Exhaust
Airflow
F
D
Supply
Airflow
D
Exhaust
Airflow
Supply
Airflow
Exhaust
Airflow
Supply
Airflow
A sq.
B
C
E
Exhaust
Airflow
Supply
Airflow