Chamberlain 3255-2M 1/2 HP, 3245M 1/3 HP Mounting and Wiring the Safety Reversing Sensors

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

Red White Grey

Safety Reversing Sensor Quick-Connect Terminals

Safety Reversing Sensor	Invisible Light Beam
	Protection Area

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