LiftMaster 3850 3850 Elite Series Manual - Page 25

ADJUSTMENT STEP 3 Test the Safety Reversal System TEST • With the door fully open, place a 1-1/2" (3.8 cm) board (or a 2x4 laid flat) on the floor, centered under the garage door. • Operate the door in the down direction. The door must reverse on striking the obstruction. ADJUST • If the door stops on the obstruction, it is not traveling far enough in the down direction. Complete Adjustment Steps 1 and 2 Program the Travel Limits and Set the Force. NOTE: On a sectional door, make sure limit adjustments do not force the door arm beyond a straight up and down position. See Figure 3, page 21. • Repeat the test. • When the door reverses on the 1-1/2" (3.8 cm) board (or 2x4 laid flat), remove the obstruction and run the opener through 3 or 4 complete travel cycles to test adjustment. • If the unit continues to fail the Safety Reverse Test, call for a trained door systems technician. IMPORTANT SAFETY CHECK: Test the Safety Reverse System after: • Each adjustment of door arm length, limits, or force controls. • Any repair to or adjustment of the garage door (including springs and hardware). • Any repair to or buckling of the garage floor. • Any repair to or adjustment of the opener. Without a properly installed safety reversal system, persons (particularly small children) could be SERIOUSLY INJURED or KILLED by a closing garage door. • Safety reversal system MUST be tested every month. • After ANY adjustments are made, the safety reversal system MUST be tested. Door MUST reverse on contact with 1-1/2" high (3.8 cm) object (or 2x4 laid flat) on the floor. 1-1/2" (3.8 cm) board (or a 2x4 laid flat) ADJUSTMENT STEP 4 Test The Protector System® • Press the remote control push button to open the door. • Place the opener carton in the path of the door. • Press the remote control push button to close the door. The door will not move more than 1" (2.5 cm), and the opener lights will flash. The garage door opener will not close from a remote if the indicator light in either sensor is off (alerting you to the fact that the sensor is misaligned or obstructed). If the opener closes the door when the safety reversing sensor is obstructed (and the sensors are no more than 6" (15 cm) above the floor), call for a trained door systems technician. Without a properly installed safety reversing sensor, persons (particularly small children) could be SERIOUSLY INJURED or KILLED by a closing garage door. Safety Reversing Sensor 25 Safety Reversing Sensor