Chamberlain 120ad Garage Door Opener User Manual


 
ALL ONE-PIECE DOORS
Assemble the Door Arm:
Fasten the straight and curved door arm sections
together to the longest possible length (with a 2 or
3 hole overlap).
With the door closed, connect the straight door
arm section to the door bracket with the
8mm x 32mm clevis pin.
Secure with a ring fastener.
Adjustment Procedures for One-Piece Doors
On one-piece doors, before connecting the door arm
to the trolley, the travel limits must be adjusted. Limit
adjustment screws are located on the left side panel
as shown on page 25. Follow adjustment procedures
below.
A. Open Door Adjustment: Decrease UP
Travel Limit
Turn the UP limit adjustment screw counter-
clockwise 4 1/2 turns.
Press the Remote Control transmitter button. The
trolley will travel to the fully open position.
Manually raise the door to the open position
(parallel to the floor), and lift the door arm to the
trolley. The arm should touch the trolley just in
back of the door arm connector hole. Refer to the
fully open trolley/door arm positions in the
illustration. If the arm does not extend far enough,
adjust the limit further. One full turn equals 50mm
of trolley travel.
B. Closed Door Adjustment: Decrease DOWN
Travel Limit
Turn the DOWN limit adjustment screw clockwise
4 complete turns.
24
Nuts
8mm
Lock
Washers
8mm
Ring
Fastener
Straight
Arm
Screws
8mm x 20mm
Door
Bracket
Clevis Pin
8mm x 32mm
Curved
Door Arm
Door Arm
Door Arm
Connector Hole
Closed
Door
Fully Closed
Trolley
Emergency Release Handle
Fully Open
Trolley
Open Door
Door with
Backward Slant
(Undesirable)
Door Arm
Connector Hole
Door Arm
Correct Angle
Nuts
8mm
L
ock
Washers
8
mm
R
ing
F
astener
S
traight
Arm
Screws
8mm x 20mm
D
oor
Bracket
Clevis Pin
8mm x 25mm
Curved
Door Arm
Door Arm
Door Arm
Connector Hole
Closed
Door
Fully Closed
Trolley
Emergency Release Handle
Fully Open
Trolley
Open Door
Door with
Backward Slant
(Undesirable)
Door Arm
Connector Hole
Door Arm
Correct Angle
Press the Remote Control transmitter button. The
trolley will travel to the fully closed position.
Manually close the door and lift the door arm to the
trolley. The arm should touch the trolley just ahead
of the door arm connector hole. Refer to the fully
closed trolley/door arm positions in the illustration.
If the arm is behind the connector hole, adjust the
limit further. One full turn equals 50mm of trolley
travel.
Connect the door arm to the trolley.
Close the door and join the curved arm to the
connector hole in the trolley with the remaining
clevis pin. It may be necessary to lift the door
slightly to make the connection.
Secure with a ring fastener.
Run the opener through a complete travel cycle. If
the door has a slight "backward" slant in full open
position as shown in the illustration, decrease the
UP limit until the door is parallel to the floor.
NOTE: When setting the up limit on the following
page, the door should not have a "backward" slant
when fully open as illustrated below. A slight
backward slant will cause unnecessary bucking
and/or jerking operation as the door is being opened
or closed from the fully open position.
114A2845