M9204-Bxx-2(Z) Series On/Off Electric Spring Return Actuators Installation Guide
6
4. Secure the anti-rotation bracket to the damper frame or duct using the two No. M3.5 x 9.5 mm
self-drilling sheet metal screws provided.
5. Slide the actuator onto the damper shaft, and position the anti-rotation bracket tab into the slot at the bottom of
the actuator as illustrated in Figure 6.
6. Rotate the damper blade(s) to the desired position if the power is lost.
7. Hold the actuator perpendicular to the damper shaft. Evenly hand-tighten each nut on the coupler U-bolt, then
torque the coupler U-bolt nuts to 100 to 125 lb·in. (11 to 14 N·m).
8. Apply power long enough for the actuator to travel a full stroke. Verify that the actuator rotates freely
throughout the range.
Limiting rotation range using M9203-603 Adjustable Stop Kit
The actuator is factory set for 95° rotation, and its range is limited in 5° increments to a minimum of 35°. A stroke-
limiting stop can be attached in the field to the shaft coupler side of the actuator to reduce the rotation range.
Attaching the stroke-limiting stop in the furthest mounting position reduces the rotation range of the actuator by 5°.
Each progressive mounting position reduces the rotation range an additional 5°.
1. Check that the damper blade is visible or its position is permanently marked on the end of the damper shaft, as
illustrated in Figure 7.
IMPORTANT:
Do not overtighten the mounting screws to avoid stripping the threads. Be certain that the tab on
the anti-rotation bracket remains properly positioned in the slot on the actuator, and that the actuator remains
parallel to the mounting surface.
Figure 6: Anti-rotation mounting bracket
F
IG
:M
920
3_ A
nt
i-
R
ot
n_
M
nt
g_Br
kt
_Po
sn
2-1/4
(57.5)
3-1/4
(82.5)
Anti-Rotation Bracket
Damper Frame
Self-Drilling Sheet Metal Screws (2)
Figure 7: Damper position icons
F
IG
:dam
pers
