Chamberlain 2000SDR 1/2 HP - Manual (Page 12)

Without a properly working safety reversing sensor,
persons (particularly children) could be injured or killed
by a closing garage door. Read and follow all
instructions.
To protect small children, install the safety reversing
sensor so that the beam will be no higher than 4"-6"
above the garage floor.
Disconnect power to the garage door opener before
installing the safety reversing sensor.
Invisible Light Beam
Protection Area
Sensor Beam
4-6" max.
above floor
Sensor Beam
4-6" max.
above floor
Facing the door from inside the garage
12
The Protector System ®
WARNING
IMPORTANT INFORMATION ABOUT THE
SAFETY REVERSING SENSOR
The safety reversing sensor must be connected and
aligned correctly before the garage door opener will
move in the down direction. This is a required safety
device and cannot be disabled.
When properly connected and aligned, the safety
reversing sensor will detect an obstacle in the path of its
electronic beam. The sending eye (with an orange
indicator light) transmits an invisible light beam to the
receiving eye (with a green indicator light). If an
obstruction breaks the light beam while the door is
closing, the door will stop and reverse to full open
position, and the opener light will flash for 5 seconds.
The units must be installed inside the garage so that the
sending and receiving eyes face each other across the
door, between 4-6" above the floor. Either can be
installed on the left or right of the door as long as the sun
never shines directly into the receiving eye lens.
The mounting brackets are designed to clip onto the
garage door track without additional hardware.
If it is necessary to mount the units on the wall, the
brackets must be securely fastened to a solid surface such
as the wall framing. Extension brackets (see Accessories)
are available if needed. If installing in masonry
construction, add a piece of wood at each location to
avoid drilling extra holes in masonry if repositioning is
necessary.
The invisible light beam path must be unobstructed. No
part of the garage door (or door tracks, springs, hinges,
rollers or other hardware) may interrupt the beam while
the door is closing.