AUTOMATIC OPPOSED BLADE DAMPERS (AOBD)
11
68-0246
SERVICE
Checking Damper Blades
Occasionally damper blades stick while opening or closing.
The problem may be caused by a worn motor switch or
binding damper blades. To locate the problem:
1.
Remove the electric actuator enclosure, if necessary.
2.
Separate the crank arm from the motor shaft using a 1-
16 Allen wrench.
3.
Using your hand, open and close the damper blades
several times by pushing and pulling the crank shaft:
a. If linkage and damper blades move freely, they are
working correctly.
b. If linkage and damper blades require effort to open
or close, replace the damper and repeat step 2.
4.
If the damper blades still require considerable effort to
open or close, check that the damper is sized correctly
and that there is no pressure on the damper blades. If
the damper is not sized correctly, replace the old
damper with a correctly-sized damper.
5.
Attach the crank arm to the motor drive shaft.
6.
If the damper blades continue to stick while opening or
closing, refer to the Installation Instruction to ensure the
mounting screws are installed correctly.
7.
Be sure the damper blades close fully by shorting termi-
nals 5 and 6. If there is a gap between damper blades:
a. Loosen the crank arm from the motor drive shaft
using a 1-16 Allen wrench.
b. Manually close the gap between the damper blades.
c. Tighten the crank arm to the motor drive shaft using
a 1-16 Allen wrench.
Checking Electric Actuator (See Fig. 16)
1.
Remove wires from the damper terminals.
2.
Connect 24 Vac to electric actuator terminals 1 and 2.
3.
Ensure the electric actuator operates correctly:
a. Remove wires from terminals 4 and 6.
b. Short terminals 4 and 5 to open the damper blades.
c. Short terminals 5 and 6 to close the damper blades.
(1) If the dampers open and close as indicated, the
system is operational.
(2) If the dampers do not operate, as indicated,
replace the electric actuator and repeat steps 1
and 2.
4.
Ensure the end-switch operates correctly:
a. Connect a 24 Vac test light between terminals 1 and
3.
b. Short terminals 4 and 5:
(1) When the damper blades are fully open, the
end-switch engages, the 24 Vac test light turns
on, and the electric actuator turns off.
c. Short terminals 5 and 6:
(1) When the damper blades are fully closed, the
end-switch engages, the 24 Vac light turns off,
and the electric actuator turns off.
5.
If the motor and end-switches do not operate, as indi-
cated, replace the electric actuator and repeat steps 1
through 4.
6.
Replace the electric actuator enclosure.
Fig. 16. Checking the electric actuator.
Replacing Electric Actuator
IMPORTANT
Electric actuator is shipped in the open damper posi-
tion.
1.
Using a 1-16 Allen wrench, loosen the crank arm set-
screw that connects the crank arm to the motor drive
shaft.
2.
Remove the crank arm from the motor drive shaft.
3.
Remove the two screws from the crank arm side of the
actuator box.
4.
Remove the electric actuator from the actuator box.
5.
Install the new electric actuator into the actuator box.
6.
Tighten the two screws into the crank arm side of the
actuator box.
7.
Attach the crank arm to the motor drive shaft.
8.
Tighten the crank arm set screw.
4
5
6
z
1
2
3
x
L1 (HOT)
L2
24V
24V
TEST
LIGHT
SHORT TERMINALS 4 AND 5 TO OPEN DAMPER BLADES.
SHORT TERMINALS 5 AND 6 TO CLOSE DAMPER BLADES.
24V TEST LIGHT TURNS ON WHEN DAMPER BLADES OPEN
AND TURNS OFF WHEN DAMPER BLADES CLOSE.
M2278A
1
2
3
1
2
3
