Connect The Door Arm To The Trolley - Chamberlain 3280CM 1/2 HP Owner's Manual

ALL ONE-PIECE DOORS
1. Assemble the door arm, Figure 4:
• 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
5/16"x1-1/4" clevis pin.
• Secure with a ring fastener.
2. Adjustment procedures, Figure 5:
• On one-piece doors, before connecting the door arm to
the trolley, the travel limits must be adjusted. Limit
adjust ment screws are located on the left side panel as
shown on page 23. Follow adjustment procedures
below.
• Open door adjustment: decrease UP travel limit
- Turn the UP limit adjustment screw counter-clockwise
4 turns.
- Press the Door Control push 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 2" (5 cm) of trolley travel.
• Closed door adjustment: decrease DOWN travel
limit
- Turn the DOWN limit adjustment screw clockwise
4 complete turns.
Figure 5
Door Arm
Inner Trolley
Outer Trolley
Door Arm
Connector Hole
Closed
Door
Inner Trolley
Correct Angle
Open Door
Door
Bracket
Clevis Pin
Straight
5/16"x1-1/4"
Arm
Figure 4
- Press the Door Control push 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
2" (5 cm) of trolley travel.

3. 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.
Emergency Release Handle
Door Arm
Door with
Backward Slant (Incorrect)
22
Ring
Fastener
Lock
Washers
5/16"
Bolts
5/16"-18x7/8
Outer Trolley
Nuts
5/16"-18
Curved
Door Arm