Chamberlain LiftMaster Security + 3270 1/2 HP Manuel D'instructions page 25

ADJUSTMENT STEP 3
Test the Safety Reversal System
TEST
1. With the door fully open, place a 1-1/2" (3.8 cm) board
(or a 2x4 laid fl at) on the fl oor, centered under the
garage door.
2. 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. Increase the DOWN
limit by turning the DOWN limit adjustment screw
counterclockwise 1/4 turn.
NOTE: On a sectional door, make sure limit adjustments
do not force the door arm beyond a straight up and
down position. See the illustration on page 21.
• Repeat the test.
• When the door reverses on the 1-1/2" (3.8 cm) board,
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 fl oor.
• Any repair to or adjustment of the opener.
ADJUSTMENT STEP 4
Test The Protector System
1. Press the remote control push button to open the door.
2. Place the opener carton in the path of the door.
3. Press the remote control push button to close the door.
The door will not move more than an inch (2.5 cm),
and the opener lights will fl ash.
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 fl oor), call for a trained door
systems technician.
®
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.
• If one control (force or travel limits) is adjusted,
the other control may also need adjustment.
• 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 fl at) on the fl oor.
1-1/2" (3.8 cm) board
(or a 2x4 laid fl at)
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