Chamberlain LJ8900W Manual page 17

Installation
ENSURE THE SAFETY REVERSING SENSORS ARE ALIGNED
The door will not close if the sensors have not been installed and aligned correctly.
When the light beam is obstructed or misaligned while the door is closing, the door
will reverse. If the door is already open, it will not close. The sensors can be aligned by
loosening the wing nuts, aligning the sensors, and tightening the wing nuts.
1. Check to make sure the LEDs in both sensors are glowing steadily. The LEDs in both
sensors will glow steadily if they are aligned and wired correctly.
Amber LED
Sending Sensor
IF THE AMBER LED ON THE SENDING SENSOR IS NOT GLOWING:
• Make sure there is power to the door operator.
• Make sure the sensor wire is not shorted/broken.
• Make sure the sensor has been wired correctly: white wires to white terminal and
white/black wires to grey terminal.
IF THE GREEN LED ON THE RECEIVING SENSOR IS NOT GLOWING:
• Make sure the sensor wire is not shorted/broken.
• Make sure the sensors are aligned.
If the receiving sensor is in direct
sunlight, switch it with sending
sensor so it is on the opposite side
of the door.
(Invisible light beam)
Green LED
Receiving Sensor
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