Chamberlain 3800PC - Manuel (Page 27)

27
Operation
Troubleshooting (Continued)
The door opens but won't close:
• Check cable tension monitor (see Installation Step 4).
• If the garage door opener lights blink, check the safety reversing sensor (see Installation Step 9).
• If the garage door opener lights don’t blink and it is a new installation (see Adjustment Step 2). For an existing installation, see below.
Repeat the safety reverse test after the adjustment is complete.
The door reverses for no apparent reason and garage door opener lights don’t blink:
• Check cable tension monitor (see Installation Step 4).
• Is something obstructing the door? Pull the emergency release handle. Operate the door manually. If it is unbalanced or binding, call a
trained door systems technician.
• Clear any ice or snow from the garage fl oor area where the door closes.
• Review Adjustment Step 2.
Repeat safety reverse test after adjustments.
The door reverses for no apparent reason and garage door 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).
The garage door 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 garage door opener and call a trained door systems technician.
The garage door opener motor hums briefl y, then won't work:
• The garage door springs may be broken. See above.
• If the problem occurs on the fi rst operation of the garage door opener, door may be locked. Disable the power door lock.
The garage door 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.
Door loses limits.
• Collar not tightened securely. Tighten collar (see Assembly Steps 1 and 2) and reprogram limits (see Adjustment Step 1).
The garage door opener 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 opener is mounted at a right angle to the jackshaft. If not, move the position of the mounting bracket.
Power lock makes noise when operating.
• Call LiftMaster ® dealer for replacement power lock.