36
C
Mechanical Operators
Symptoms And Solutions
SYMPTOM:
Door Drifts After The Operator Is Shut Off
POSSIBLE CAUSE:
SOLUTION:
Brake needs adjusting (if present)
Check and adjust brake.
Door poorly balanced
Check and adjust door/springs.
SYMPTOM:
Door Travels Down And Then Stops And Reverses
POSSIBLE CAUSE:
SOLUTION:
A sensing device is being activated
Check wiring of the sensing device.
Radio receiver may be sending a long signal
to the operator; this can cause the operator
to travel down off the open limit, then reverse
again
Try disconnecting the receiver. If the problem disappears, use a
LiftMaster Brand Receiver
SYMPTOM:
Door Opens And Then Stops Short Of The Full Open Position
POSSIBLE CAUSE:
SOLUTION:
Limit nut not set correctly
Adjust limit nut.
An obstruction may be preventing the proper
operation of the door
Check door for obstruction.
The clutch may need adjustment
Check the sensitivity of the clutch.
Defective limit switch activating prematurely
Check limit switch; replace if necessary.
SYMPTOM:
Operator Does Not Open Or Close In Response To Command From 3-Button Control Station
POSSIBLE CAUSE:
SOLUTION:
Bad wire to 3-button control station
Recheck wiring.
Circuit breaker has tripped
Reset circuit breaker.
Damaged transformer
Check transformer and circuit for 24V.
If equipped with electric interlock, there may
be a poor contact to the interlock switch
Verify all interlock switches are working correctly and wiring is
making good contact.
Blown fuse
Replace fuse.
SYMPTOM:
The Door Will Not Close Completely
POSSIBLE CAUSE:
SOLUTION:
The limit assembly depression plate is not
properly engaged with nylon limit nut
Check and adjust if necessary.
The door is binding or meeting an obstruction
Look for obstruction.
Loose drive or limit chain can cause the chain
to “jump” the sprocket teeth
Check the chain as necessary. The limit chain can be adjusted/
tensioned at the electrical box assembly via two mounting screws.
SYMPTOM:
Motor Runs In Wrong Direction
POSSIBLE CAUSE:
SOLUTION:
Operator is upside down
For MJ, install operator with motor toward the ceiling. For MT,
the electrical box and motor should be toward the floor. Correct if
necessary.
Motor is wired incorrectly
Check and correct wiring.
Three-phase wires are in the wrong order
Rearrange any two incoming three-phase power legs on the
terminal strip.
Summary of Contents for K001A5729
Page 1: ...For more information please visit www devancocanada com or call toll free at 855 931 3334...
Page 4: ...4 Page Basic Troubleshooting 5 SECTION A Table of Contents...
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Page 34: ...Page Symptoms And Solutions 35 Mechanical Operators SECTION C Table of Contents...
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Page 62: ...62 WARNING F Wiring Diagrams Mechanical Operator Single Phase...
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