Chamberlain LiftMaster Security+ 3265CM Manuel D'instructions page 24

ADJUSTMENT STEP 2
Adjust the Force
Force adjustment controls are located on the back panel
of the motor unit. Force adjustment settings regulate the
amount of power required to open and close the door.
If the forces are set too light, door travel may be
interrupted by nuisance reversals in the down direction
and stops in the up direction. Weather conditions can
affect the door movement, so occasional adjustment may
be needed.
The maximum force adjustment range is about 3/4 of a
complete turn. Do not force controls beyond that point.
Turn force adjustment controls with a screwdriver.
NOTE: If anything interferes with the door's upward travel,
it will stop. If anything interferes with the door's downward
travel (including binding or unbalanced doors), it will
reverse.
HOW AND WHEN TO ADJUST THE FORCES
1. Test the DOWN (close) force
• Grasp the door bottom when the door is about halfway
through DOWN (close) travel. The door should reverse.
Reversal halfway through down travel does not
guarantee reversal on a 1-1/2" (3.8 cm) obstruction.
See Adjustment Step 3, page 25. If the door is hard
to hold or does not reverse, DECREASE the DOWN
(close) force by turning the control counterclockwise.
Make small adjustments until the door reverses
normally. After each adjustment, run the opener
through a complete cycle.
• If the door reverses during the down (close) cycle and
the opener lights are not fl ashing, INCREASE DOWN
(close) force by turning the control clockwise. Make
small adjustments until the door completes a close
cycle. After each adjustment, run the opener through
a complete travel cycle. DO NOT increase the force
beyond the minimum amount required to close the
door.
2. Test the UP (open) force
• Grasp the door bottom when the door is about halfway
through UP (open) travel. The door should stop. If the
door is hard to hold or does not stop, DECREASE UP
(open) force by turning the control counterclockwise.
Make small adjustments until the door stops easily
and opens fully. After each adjustment, run the opener
through a complete travel cycle.
• If the door does not open at least 5 feet (1.5 m),
INCREASE UP (open) force by turning the control
clockwise. Make small adjustments until door opens
completely. Readjust the UP limit if necessary. After
each adjustment, run the opener through a complete
travel cycle.
Without a properly installed safety reversal system,
persons (particularly small children) could be
SERIOUSLY INJURED or KILLED by a closing garage
door.
• Too much force on garage door will interfere with
proper operation of safety reversal system.
• NEVER increase force beyond minimum amount
required to close garage door.
• NEVER use force adjustments to compensate for a
binding or sticking garage door.
• 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 fl oor.
Back Panel
FORCE ADJUSTMENT LABEL
Open Force
24
Force
Adjustment
Controls
Antenna
Close Force