Safety Sensors Troubleshooting - Chamberlain LiftMaster 3275C Owner's Manual

MOUNTING AND WIRING THE SAFETY REVERSING SENSORS
• Slide a 1/4"-20x1/2" carriage bolt head into the slot on each
sensor. Use wing nuts to fasten sensors to brackets, with
lenses pointing toward each other across the door. Be sure the
lens is not obstructed by a bracket extension (Figure 5).
• Finger tighten the wing nuts.
• Run the wires from both sensors to the opener. Use insulated
staples to secure wire to wall and ceiling.
• Strip 7/16" (11 mm) of insulation from each set of wires.
Separate white and white/black wires sufficiently to connect to
the opener quick-connect terminals. Twist like colored wires
together. Insert wires into quick-connect holes: white to white
and white/black to grey (Figure 6).
ALIGNING THE SAFETY REVERSING SENSORS
• Plug in the opener. The indicator lights in both the sending and
receiving eyes will glow steadily if wiring connections and
alignment are correct.
The sending eye amber indicator light will glow regardless of
alignment or obstruction. If the green indicator light in the
receiving eye is off, dim, or flickering (and the invisible light beam
path is not obstructed), alignment is required.
• Loosen the sending eye wing nut and readjust, aiming directly
at the receiving eye. Lock in place.
• Loosen the receiving eye wing nut and adjust sensor until it
receives the sender's beam. When the green indicator light
glows steadily, tighten the wing nut.
Figure 6
Bell Wire
Safety Reversing Sensor
Finished
Ceiling
Bell Wire
Safety Reversing Sensor
Invisible Light Beam
Protection Area
Figure 5
Carriage Bolt
1/4"-20x1/2"
TROUBLESHOOTING THE SAFETY REVERSING SENSORS
1. If the sending eye indicator light does not glow steadily after
installation, check for:
• Electric power to the opener.
• A short in the white or white/black wires. These can occur at
staples, or at opener connections.
• Incorrect wiring between sensors and opener.
• A broken wire.
2. If the sending eye indicator light glows steadily but the
receiving eye indicator light doesn't:
• Check alignment.
• Check for an open wire to the receiving eye.
3. If the receiving eye indicator light is dim, realign either sensor.
NOTE: When the invisible beam path is obstructed or misaligned
while the door is closing, the door will reverse. If the door is
already open, it will not close. The opener lights will blink
10 times. See page 16.
Connect Wire to
Opener Quick-Connect Terminals
18
Wing Nut
1/4"-20
Lens
1. Strip wire 7/16"
7/16"
(11 mm)
(11mm)
2. Twist like colored
wires together
3. To release or insert
wire, push in tab with
screwdriver tip
Red White Grey
Quick-Connect Terminals