LiftMaster 3950 3950 Manual - Page 10

INSTALLATION STEP 6 Install The Protector System® The safety reversing sensor must be connected and aligned correctly before the door operator will move in the down direction. This is a required safety device and cannot be disabled. IMPORTANT INFORMATION ABOUT THE SAFETY REVERSING SENSOR 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 amber 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. The units must be installed inside the building so that the sending and receiving eyes face each other across the door, no more than 6" (15 cm) 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. Be sure power is not connected to the door operator BEFORE installing the safety reversing sensor. To prevent SERIOUS INJURY or DEATH from a closing door: • Correctly connect and align the safety reversing sensor. This required safety device MUST NOT be disabled. • Install the safety reversing sensor so beam is NO HIGHER than 6" (15 cm) above floor. 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 door (door tracks, springs, hinges, rollers or other hardware) may interrupt the beam while the door is closing. Safety Reversing Sensor 6" (15 cm) max. above floor Invisible Light Beam Protection Area Facing the door from inside. Safety Reversing Sensor 6" (15 cm) max. above floor 10