Adjustment Section: Pages - Chamberlain 1200 Owner's Manual

Adjustment Step 1
Adjust the UP and DOWN Limits
Limit adjustment settings regulate the points at
which the door will stop when moving up or down.
The door will stop in the up direction if anything
interferes with door travel. The door will reverse in
the down direction if anything interferes with the
door travel (including binding or unbalanced doors).
To operate the opener, press the Door Control
button/push bar. Run the opener through a
complete travel cycle.
• Does the door open and close completely?
• Does the door stay closed and not reverse
unintentionally when fully closed?
If your door passes both of these tests, no limit
adjustments are necessary.
Adjustment procedures are outlined below. Run the opener through a complete travel cycle after each
adjustment.
Repeated operation of the opener during adjustment procedures may cause the motor to overheat and
shut off. Simply wait 15 minutes and try again.
Read the procedures carefully before continuing on to Adjustment Step 2. Use a screwdriver to make limit
adjustments.
If the door does not open completely
but opens at least five feet
Increase up travel. Turn the UP limit adjustment
screw clockwise. One turn equals 2" of travel.
If door does not open at least 5 feet:
Adjust the UP (open) force as explained in
Adjustment Step 2.
If the door does not close completely
Increase down travel. Turn the DOWN limit
adjustment screw counterclockwise. One turn
equals 2" of travel.
If door still won't close completely, try lengthening
the door arm. (See page 26.)
If you have adjusted the door arm to the maximum
length and the door still will not close completely,
lower the header bracket. See Installation Step 1,
pages 12 and 13.
Adjustment Section: Pages 28 – 30
How and When to Adjust the Limits
Improper adjustment of the travel limits will
interfere with the proper operation of the safety
reverse system. The door might not reverse
when required and could seriously injure or kill
someone under it. Test the safety reverse
system following all adjustments to the travel
limits. See page 30.
If the opener reverses in fully closed position
Decrease down travel. Turn the DOWN limit
adjustment screw clockwise. One turn equals 2"
of travel.
If the door reverses when closing and
there is no visible interference to travel cycle
If the opener lights are flashing, the Safety Reversing
Sensor is obstructed. Remove the obstruction.
Test the door for binding: Pull the manual release
handle. Manually open and close the door. If the door
is binding, call for garage door service. If the door is
not binding or unbalanced, adjust the DOWN (close)
force. See Adjustment Step 2.
28
WARNING
INCREASE TRAVEL
DOWN UP
Left Side
Panel
INCREASE TRAVEL
DOWN
UP
Adjustment Label
Limit
Adjustment
Screws