Craftsman 139.18452D Manuel D'instructions page 28

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 29. If the
door is hard to hold or doesn't 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 aren't flashing, 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 doesn't 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 doesn't 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 flat) on floor.
Back Panel
ADJUSTMENT LABEL
Open Force
28
WARNING
CAUTION
Force Adjustment
Controls
Close Force