Diagnostics Chart; Programming; To Add Or Reprogram A Hand-Held Remote Control; To Erase All Codes From Motor Unit Memory - Chamberlain LiftMaster LM3800A Instructions Manual

Diagnostic Chart
Your door operator is programmed with self-diagnostic capabilities. The "Learn" button/diagnostic LED will flash a number of times then pause
signifying it has found a potential issue. Consult Diagnostic Chart below.
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 flashing LED).
5 FLASHES
Possible RPM sensor
failure. Unplug to reset.
9 FLASHES
Cable tension monitor
reversal.

PROGRAMMING

Your door operator has already been programmed at the factory to
operate with your hand-held remote control. The door will open and close
when you press the large push button.
Below are instructions for programming your operator to operate with
additional remote controls.
To Add or Reprogram a Hand-held Remote
Control
USING THE "LEARN" BUTTON
1. Press and release the orange "learn" button on the motor unit. The
learn indicator LED will glow steadily for 30 seconds.
2. Within 30 seconds, press and hold the button on the hand-held remote
that you wish to operate your door.
3. Release the button when the motor unit LED two clicks.
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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 30-60mm 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 flashing.
• Realign receiving eye sensor, clean lens and secure brackets.
• Verify door track is firmly secured to wall and does not move.
Symptom: The RPM Sensor = Short travel 150-200mm.
• Unplug unit to reset. Try to operate motor unit, check diagnostic code.
• If it is still flashing 5 times and motor unit moves 150-200mm (6-8"),The unit's APE (Absolute Positioning
Encoder) may need to be replaced, for details contact your Chamberlain reseller.
Symptom: Door reverses while closing.
• Check for possible door obstructions and remove.
• Check that the cable tension monitor is properly connected to the operator.
• Replace the cable tension monitor.
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To Erase All Codes From
Motor Unit Memory
To deactivate any unwanted remote, first erase all codes:
Press and hold the "learn" button on motor unit until the learn indicator
LED goes out (approximately 6-9 seconds). All previous codes are now
erased. Reprogram each remote or keyless entry you wish to use.
The Remote Control Battery
To prevent possible SERIOUS INJURY or DEATH:
• NEVER allow small children near batteries.
• If battery is swallowed, immediately notify doctor.