6
Twin City IM-4800
FAN
AIR
FLOW
BACKDRAFT
DAMPER
SPACER
(BY OTHERS)
MIN
To achieve the minimum 'M' dimension,
this installation requires a spacer (by others)
between the fan and the wall.
If the wall is equal to or greater than the
minimum 'M' dimension, the fan can be
mounted directly to the wall.
Wall Opening Requirements
Wall opening size and the distance between propeller and damper are two important dimensions for fan installation.
Fans mounted to the wall require a different wall opening size than those mounted in collars or wall boxes. Propeller-
to-damper distance (M) is important to reduce turbulence at the damper which may lead to premature failure, and to
prevent the propeller blades from hitting the actuator on motorized damper units. Use general installation procedure
from page 5.
PROP
SIZE
PANEL SQ.
WALL OPENING (MIN.)
DAMPER SIZE
'M'
(MIN.)
SURFACE MOUNT
RECESS (IN WALL)
WPB
WPD
WPB
WPD
WPB
WPD
WPB
WPD
14
--
17.00
--
14.50
--
17.50
--
14 x 14
16.00
16
--
20.00
--
17.50
--
20.50
--
17 x 17
18
--
22.00
--
19.50
--
22.50
--
19 x 19
21
25.00
25.00
22.50
22.50
25.50
25.50
22 x 22
22 x 22
16.00
24
28.00
28.00
25.50
25.50
28.50
28.50
25 x 25
25 x 25
30
36.00
36.00
33.50
33.50
36.50
36.50
33 x 33
33 x 33
36
42.00
42.00
39.50
39.50
42.50
42.50
39 x 39
39 x 39
16.00
42
48.00
48.00
45.50
45.50
48.50
48.50
45 x 45
45 x 45
48
54.00
54.00
51.50
51.50
54.50
54.50
51 x 51
51 x 51
54
60.00
--
57.50
--
60.50
--
57 x 57
--
19.00
60
66.00
--
63.50
--
66.50
--
63 x 63
--
Panel Installation (without accessories) — WPB & WPD
