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 5:
IMPORTANT: The groove on the straight door arm
MUST face away from the curved 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 5/16"x1-1/4"
clevis pin.
• Secure with a ring fastener.
2. Adjustment procedures, Figure 6:
• 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 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 fl oor), 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.
- Press the door control push button. The trolley will
travel to the fully closed position.
Figure 6
Inner Trolley
Door Arm
Connector Hole
Door Arm
Closed
Door
Outer Trolley
Emergency Release
Handle
Inner Trolley
Correct Angle
Open Door
Figure 5
CORRECT
Straight
Door
Curved
Arm
Door
Arm
(Groove
facing out)
Door
Bracket
Clevis Pin
Straight
5/16"x1-1/4"
Arm
- 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 fl oor.
NOTE: When setting the up limits 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.
Door Arm
Door with
Backward Slant (Incorrect)
22
INCORRECT
Straight
Door
Arm
Ring
Lock
Fastener
Washers
5/16"
Bolts
5/16"-18x7/8
Outer Trolley
Curved
Door
Arm
Nuts
5/16"-18
Curved
Door Arm