Craftsman 139.18451DM Manuel D'instructions page 33

Having a Problem?
1. My door will not close and the light bulbs blink on my motor
unit: The safety reversing sensor must be connected and
aligned correctly before the garage door opener will move in the
down direction.
• Verify the safety sensors are properly installed, aligned and
free of any obstructions. Refer to Installation Step 10: Install
The Protector System ® .
• Check diagnostic LED for fl ashes on the motor unit then refer
to the Diagnostic Chart on the following page.
2. My remotes will not activate the door:
• Reprogram remotes following the programming instructions.
Refer to Programming.
• If remote will still not activate your door, check diagnostic
LED for fl ashes on motor unit then refer to Diagnostic Chart
on the following page.
3. My door reverses for no apparent reason: Repeat safety
reverse test after adjustments to force or travel limits. The need
for occasional adjustment for the force and limit settings is
normal. Weather conditions in particular can affect door travel.
• Manually check door for balance or any binding problems.
• Refer to Adjustment Step 2, Adjust the Force.
4. My door reverses for no apparent reason after fully closing
and touching the fl oor: Repeat safety reverse test after
adjustments to force or travel limits. The need for occasional
adjustment for the force and limit settings is normal. Weather
conditions in particular can affect door travel.
• Refer to Adjustment Step 1, Adjust the UP and DOWN
Travel Limits. Decrease down travel by turning down limit
adjustment screw clockwise.
5. My lights will not turn off when door is open:
• The garage door opener is equipped with a security light
feature. This feature activates the light on when the safety
sensor beam has been obstructed.
Safety Reversing Sensor
Sending Eye Safety Reversing
Sensor (Amber Indicator Light)
6. My motor unit hums briefl y:
• First verify that the trolley is against the stop bolt.
• Release the door from the opener by pulling the emergency
release rope.
• Manually bring the door to a closed position.
• Loosen the chain by adjusting the outer nut 4 to 5 turns.
This relieves the tension.
• Run the motor unit from the remote control or door control.
The trolley should travel towards the door and stop. If the
trolley re-engages with the door, pull the Emergency Release
Rope to disengage.
• Decrease the up travel by turning the UP travel adjustment
screw 2 full turns away from the arrow.
• Re-tighten the outer nut so the chain is a 1/4" (6 mm) above
the base of the rail. (When the door is reconnected and
closed, the chain will sag. This is normal.)
• If the trolley does not move away from the bolt, repeat the
steps above.
33
Bell Wire
Diagnostics
Located On
Motor Unit
LED or
Diagnostic
LED
"Learn"
Button
Receiving Eye Safety Reversing
Sensor (Green Indicator Light)