Chamberlain LiftMaster Security + 3270 1/2 HP Manuel D'instructions page 30

Bell Wire
Safety Reversing Sensor
Diagnostic Chart
1 FLASH
Safety reversing sensors
wire open (broken or
disconnected).
OR
2 FLASHES
Safety reversing
sensors wire shorted
or black/white wire
reversed.
3 FLASHES
Door control or
wire shorted.
4 FLASHES
Safety reversing sensors
slightly misaligned (dim
or fl ashing LED).
5 FLASHES
Motor overheated or
possible RPM sensor
failure. Unplug to reset.
6 FLASHES
Motor Circuit Failure.
Replace Receiver
Logic Board.
Diagnostics
Located On
Motor Unit
LED or
Diagnostic
LED
"Learn"
Button
Symptom: One or both of the Indicator lights on the safety reversing sensors do not
glow steady.
• Inspect sensor wires for a short (staple in wire), correct wiring polarity (black/white
wires reversed), broken or disconnected wires, replace/attach as needed.
• Disconnect all wires from back of motor unit.
• Remove sensors from brackets and shorten sensor wires to 1-2 ft. (30-60 cm) from
back each of sensor.
• Reattach sending eye to motor unit using shortened wires. If sending eye indicator
light glows steadily, attach the receiving eye.
• Align sensors, if the indicator lights glow replace the wires for the sensors. If the
sensor indicator lights do not light, replace the safety reversing sensors.
Symptom: LED is not lit on door control.
• Inspect door control/wires for a short (staple in wire), replace as needed.
• Disconnect wires at door control, touch wires together. If motor unit activates,
replace door control.
• If motor unit does not activate, disconnect door control wires from motor unit.
Momentarily short across red and white terminals with jumper wire. If motor unit
activates, replace door control wires.
Symptom: Sending indicator light glows steadily, receiving indicator light is dim
or fl ashing.
• Realign receiving eye sensor, clean lens and secure brackets.
• Verify door track is fi rmly secured to wall and does not move.
Symptom: Motor has over heated; the motor unit does not operate or trolley is stuck
on stop bolt = Motor unit hums briefl y; RPM Sensor = Short travel 6-8" (15-20 cm).
• Unplug unit to reset. Try to operate motor unit, check diagnostic code.
• If it is still fl ashing 5 times and motor unit moves 6-8" (15-20 cm), replace RPM
sensor.
• If motor unit doesn't operate, motor unit is overheated. Wait 30 minutes and retry. If
motor unit still will not operate replace logic board.
Symptom: Motor unit doesn't operate.
• Replace logic board because motor rarely fails.
Installed Safety
Reversing Sensor
Your garage door opener is programmed with
self-diagnostic capabilities. The "Learn" button/diagnostic
LED will fl ash a number of times then pause signifying
it has found a potential issue. Consult Diagnostic Chart
below.
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