Chamberlain HD220C Manual page 18

Installation
STEP 9 Connect the door arm to the trolley
IMPORTANT: The groove on the straight door arm MUST face away from the curved door arm.
1. Close the door. Disconnect the trolley by pulling the emergency release handle.
2. Attach the straight door arm to the outer trolley using the clevis pin. Secure with the ring fastener.
3. Attach the curved door arm to the door bracket using the clevis pin. Secure with the ring fastener.
4. Bring arm sections together. Find two pairs of holes that line up and join sections. Select holes as
far apart as possible to increase door arm rigidity and attach using the bolts and nuts.
5. Pull the emergency release handle toward the garage door opener until the trolley release arm
is horizontal. The trolley will re-engage automatically when the garage door opener is activated.
Clevis Pin 5/16"x1-1/4"
Ring Fastener
HARDWARE
Clevis Pin 5/16"x1" Hex Bolt 1/4"-20x3/4"
Lock Nut 1/4"-20
CORRECT
Straight
Door Arm
(Groove
facing
out)
Ring Fastener
Lock Nut
1/4"-20
17
INCORRECT
Straight
Door
Curved
Arm
Door
Arm
Clevis Pin
5/16"x1"
Hex Bolt 1/4"-20x3/4"
Clevis Pin 5/16"x1-1/4"
Curved
Door
Arm