Connect The Door Arm To The Trolley - Chamberlain LiftMaster 3275C 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.
- Press the Door Control push button. The trolley will travel to
the fully closed position.
Figure 5
Inner Trolley
Outer Trolley
Door Arm
Connector Hole
Door Arm
Closed
Door
Inner Trolley
Correct Angle
Open Door
Door
Bracket
Clevis Pin
Straight
5/16"x1-1/4"
Arm
Bolts
5/16"-18x7/8
Figure 4
- 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
Nuts
Lock
5/16"-18
Washers
5/16"
Outer Trolley
Curved
Door Arm