Chamberlain 9902 - Manual (Page 18)

18
Installation Step 4
(Continued)
Install the Safety Reversing Sensor
Invisible Light Beam
Protection Area Sensor
Sensor
Bell Wire
Foam
Packaging
Carton
2. Run wires along channels
to power unit and pull taut.
1. Run wires from sensors to end of rail
at the door header. Cross & twist here to
help contain wires in channels on top of rail.
3. Thread wires through tabs
on top of Drive Shaft Cover.
4. With screwdriver blade,
tuck wires snugly into channels.
Header
Bracket
Header
Wall
Sensor
Wire
Twist
Wires
Sensor
Wire
Rail
Channel
Figure 5
A
B
Figure 4
1/4"-20x1/2"
Carriage bolt
Lens
Wing nut
Mounting and Wiring the Safety 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. See Figure 4.
• Finger tighten the wing nuts.
Recommended Wire Routing
1. Using insulated staples, run the wires from both
sensors to the rail at the door header (see Figure 5).
2. Cross and twist the two wires where they meet the rail
(see inset A). Run the wires inside the channels at the
top of the rail, along each side, to the power unit and
pull taut (see inset B). Do not use the lower (trolley)
channels.
NOTE: If your access door is near the garage door,
you may choose to install the door control at this time
and run the door control wire along the rail with the
sensor wires. Use one rail channel for the door control
wire and the other channel for both sensor wires. If
you choose this option, follow instructions 1-3
on page 21 now.
3. Thread the wires through the tabs on top of the drive
shaft cover.
4. With your screwdriver tip, tuck the wires snugly into
the rail channels. You will complete the wiring in
Installation Step 7.
Wing Nut Staples 1/4"-20x1/2"
Carriage Bolt
Hardware Shown Actual Size