Craftsman 139.18076 Owner's Manual

Having a Problem?(continued)Situation Probable Cause & SolutionThe door reverses forno apparent reasonand opener lightsdon't blink:1. Is something obstructing the door? Pull the red emergency release handle. Operatethe door manually. If it is unbalanced or binding, call for professional garage doorservice.2. Clear any ice or snow from the garage floor area where the door closes.3. Review the force adjustment procedures on page 29.4. If door reverses in thefully closed position, decrease the travel limits (page 28).Repeat safety reverse test after adjustments to force or travel limits. The needfor occasional adjustment of the force and limit settings is normal. Weatherconditions in particular can affect door travel.The door reverses forno apparent reasonand opener lightsblink for 5 secondsafter reversing:The opener light: . . . doesn't turn on:Replace the light bulbs (75 watts maximum). Use astandard neck garage door openerbulb if regular bulb burns out.. . . doesn't turn off:Is the Light featureon? Turn itoff.The opener strains ormaximum force isneeded to operatedoor:The door may be out of balance or the springs are broken. Close the door and use theemergency release to disconnect the trolley. Open and close the door manually. A properlybalanced door will stay in any point of travel while being supported entirely by its springs. If itdoes not, disconnect the opener and call a professional garage door serviceman.Do notincrease the force to operate the opener.The opener motorhums briefly, thenwon't work:1. The garage door springs are broken. See above.2. If the problem occurs on the first operation of the opener, door may be locked.Disablethe door lock. If the chain was removed and reinstalled, the motor may be out of phase.Remove the chain; cycle the motor to the down position. Observe the drive sprocket.When it turns in a clockwise direction and stops in the down position, reinstall the chain.Repeat the safety reverse test after the adjustment is complete.The opener won'toperate due topower failure:1. Use the emergency release to disconnect the trolley. The door can be opened and closedmanually. When the power is restored, press the Door Control push button and trolley willautomatically reconnect (unless trolley is in lockout position.) See page 32.2. The Emergency Key Release accessory (for use on garages with no service door)disconnects the trolley from outside the garage in case of power failure.The chain droopsor sags:It is normal for the chain to droop slightly in the closed door position. Use theemergency release to disconnect the trolley. If the chain returns to normal height whenthe trolley is disengaged and the door reverses on a one-inch board, no adjustmentsare needed (see page 11).35The door opens butwon't close:Check the safety reversing sensor. Remove any obstruction or align the receiving eye.See page 23.1. If the opener lights blink, check the safety reversing sensor. See page 23.2. If the opener lights do not blink and it is a new installation, check the down force.See Adjustment Step 2, page 29. For an existing installation, see below.Repeat the safety reverse test after the adjustment is complete.