Chamberlain 1120E-1/2HP Owner's Manual page 22

ASSEMBLE DOOR ARM: Fasten straight and
curved door arm sections together to their longest
possible length (with a 2 or 3 hole overlap). With
door closed, connect straight door arm section to
door bracket with a clevis pin. Secure with a ring
fastener.
Before connecting door arm to trolley, limits of travel must be adjusted on one-piece doors. Limit adjustment
screws are located on left side panel as shown in illustration on page 23. Follow procedures below.
Door Arm
Closed Door
Open Door Adjustment:
Decrease UP limit
• Turn the UP limit adjustment screw counter-
clockwise 5-1/2 turns.
• Press the Door Control push bar or 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 5cm 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.
ONE-PIECE DOORS
Fully Closed
Trolley
Door Arm
Connector Hole
Open Door
Adjustment Procedures for One-Piece Doors
22
Door
Ring
Bracket
Fastener
Clevis Pin
Straight
Arm
Screws
5/16"-18x7/8"
13mm Socket Wrench
Door Arm
Connector Hole
Door Arm
Door Arm
Bracket
Closed Door Adjustment:
Decrease DOWN limit
• Turn the DOWN limit adjustment screw clockwise 5
complete turns.
• Press the Door Control push bar or 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 5cm of trolley travel.
Nuts
Lock
5/16"-18
Washers
5/16"
Curved
Door Arm
Fully Open
Trolley