Trouble Shooting - Chamberlain ML750 Installation And Operating Instructions Manual

TROUBLE SHOOTING

1. Opener doesn't operate from either door control or remote:
• Does the opener have electric power? Plug lamp into outlet. If it
doesn't light, check the fuse box or the circuit breaker. (Some outlets
are controlled by a wall switch.)
• Have you disengaged all door locks? Review installation instruction
warnings on page 1.
• Is there a build-up of ice or snow under door? The door may be
frozen to ground. Remove any obstruction.
• The garage door spring may be broken. Have it replaced.
2. Opener operates from remote but not from door control:
• Is door control button lit? If not, remove the bell wire from the opener
terminals. Short the red and white terminals by touching both
terminals at the same time with a piece of wire. If the opener runs,
check for a faulty wire connection at the door control, a short under
the staples, or a broken wire.
• Are wiring connections correct? Review section 27.
3. Door operates from door control but not from remote:
• Replace battery if necessary.
• If you have two or more remotes and only one operates, review
wireless programming, keyless device programming sections 25 and
26.
• Is the door control button flashing? The opener is in lock mode. If you
have a multi-function door control, push and hold the lock button for
2 seconds. The door control button will stop flashing.
4. Remote has short range:
• Is battery installed? Check or change battery.
• Change the location of the remote control in the car.
• A metal garage door, foil-backed insulation or metal siding will reduce
the transmission range.
5. Door reverses for no apparent reason and opener light doesn't
flash:
• Is something obstructing the door? Pull manual release handle.
Operate door manually. If it is unbalanced or binding, call for
professional garage door service.
• Clear any ice or snow from garage floor area where garage
door closes.
• Repeat setting limits and force, see adjustment sections 21 and 22.
Repeat safety reverse test after adjustment is complete.
6. Door reverses for no apparent reason and opener light flashes
for 5 seconds after reversing:
• Check the Protector System™ (if you have installed this accessory).
If the light is flashing, correct alignment.
7. The garage door opens and closes by itself:
• Make sure remote push button is not stuck "on".
8. Door stops but doesn't close completely:
• Repeat setting the limits, see adjustment section 21.
• Repeat safety reverse test after any adjustment of door arm length,
close force or down limit.
9. Door opens but won't close:
• Check the Protector System™ (if you have installed this accessory).
If the light is flashing, correct alignment.
• If opener light does not flash and it is a new installation, repeat setting
the limit and force sections 21 and 22.
• Repeat the safety reverse test after the adjustment is complete.
10. Opener light does not turn on:
• Replace light bulb (24V/21W maximum).
11. Opener strains:
• Door may be unbalanced or springs are broken. Close door and use
manual release rope and handle to disconnect trolley. Open and close
door manually. A properly balanced door will stay in any point of travel
while being supported entirely by its springs. If it does not, call for
professional garage door service to correct the problem.
12. Opener motor hums briefly, then won't work:
• Garage door springs are broken. SEE ABOVE.
• If problem occurs on first operation of opener, door is locked. Disable
door lock.
• Repeat safety reverse test after adjustment is complete.
13. Opener won't activate due to power failure:
• Pull manual release rope and handle down and back to disconnect
trolley. Door can be opened and closed manually. When the power is
restored, pull the manual release handle straight down. The next time
the opener is activated, the trolley will reconnect.
• The outside quick release accessory (if fitted) disconnects the trolley
from outside the garage in case of power failure.
14. Setting the limits manually:
1. Press and hold the black button until the yellow indicator light starts
flashing slowly then release.
2. Push and hold the black button until the door reaches the desired UP
(open) position. Adjust the position of the door by using the black and
orange buttons. Black moves the door UP (open) and orange moves
the door DOWN (close).
Check to be sure the door opens high enough for your vehicle.
3. Push the remote control or door control. This sets the UP (open) limit
and begins closing the door. Immediately press either the orange
or the black button. The door will stop.
Adjust the desired DOWN (closed) limit by using the orange (DOWN)
and black (UP) buttons. Check to be sure the door is fully closed
without applying excessive pressure on the rail (rail should not bow
upwards and the belt should not sag or droop below the rail). Push
the remote control or door control. This sets the DOWN (close) limit
and begins opening the door.
NOTE: If neither the BLACK or the ORANGE button is pressed, the
door will reverse off the floor and the DOWN travel limit will be set
automatically.
4. Open and close the door with the remote control or door control 2
or 3 times.
• If the door does not stop in the desired UP (open) position or reverses
before the door stops at the DOWN (close) position, repeat setting
the limits manually one more time.
• If the door stops in both the desired UP (open) and DOWN (close)
positions, proceed to test the safety reversal system.
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