Chamberlain 3800E - Manual (Page 25)

25
Having a Problem? (Continued)
9. The door reverses for no apparent reason and
opener lights blink for 5 seconds after reversing:
• Check the safety reversing sensor. Remove any
obstruction or align the receiving eye. See Installation
Step 9.
10. The opener strains to operate door:
• The door may be out of balance or the springs may be
broken. Close the door and use the emergency
release handle to disconnect the door. Open and close
the door manually. A properly balanced door will stay
in any point of travel while being supported entirely by
its springs. If it does not, disconnect the opener and
call a trained door systems technician.
11. The opener motor hums briefly, then won't work:
• The garage door springs may be broken. See above.
• If the problem occurs on the first operation of the
opener, door may be locked. Disable the power door
lock.
12. The opener won't operate due to power failure:
• Manually open the power door lock.
• Use the emergency release handle to disconnect the
door. The door can be opened and closed manually.
When power is restored, pull manual release a second
time.
• If a Standby Power Unit is connected, the opener
should be able to operate up to 20 times without
power.
13. Door loses limits.
• Collar not tightened securely. Tighten collar
(see Assembly Steps 1 and 2) and reprogram limits
(see Adjustment Step 1).
14. The operator moves when the door is in operation:
• Some minor movement is normal for this product. If it
is excessive the collar will wear prematurely.
• Check to make sure the torsion bar is not moving left/
right excessively.
• Check to make sure the torsion bar is not visibly
moving up and down as it rotates.
• Check that the operator is mounted at a right angle to
the jackshaft. If not, move the position of the mounting
bracket.
15. Power lock makes noise when operating.
• Call Liftmaster ® dealer for replacement power lock.