Assembly - Chamberlain HD220 Owner's Manual

Assembly

STEP 1 Assemble the rail and trolley
To prevent INJURY from pinching, keep hands and fingers away from the joints while assembling the
rail.
To avoid installation difficulties, do not run the garage door opener until instructed to do so.
The front rail has a cut out "window" at the door end (see illustration). The front rail has a rail tab. This tab
MUST be on the top of the rail when assembled.
1. Remove the straight door arm and hanging bracket packaged inside the front rail and set aside
for Installation Step 5 and 9. NOTE: To prevent INJURY while unpacking the rail carefully remove
the straight door arm stored within the rail section.
2. The rail sections have a groove on the sides near the bottom edge. Use these grooves to align
the rail sections. Slide the tapered ends into the larger ones. Tabs along the side will lock into
place.
3. Place the motor unit on packing material to protect the cover, and rest the back end of the rail on
top. For convenience, put a support under the front end of the rail.
4. As a temporary stop, insert a screwdriver into the hole 10" (25 cm) from the front end of the rail,
as shown.
5. Check to be sure there are 4 plastic wear pads inside the inner trolley. If they became loose
during shipping, check all packing material. Snap them back into position as shown.
6. Slide the trolley assembly toward the screwdriver as shown.
7. Slide the chain spreader onto the rail until it stops.
Outer Trolley
Inner Trolley
Wear Pads
Trolley
Rail
Front Rail
Tab
Section
Idler
(TO DOOR)
Pulley
Hole
Window
Cut-Out
5
To garage
door opener
(TO MOTOR UNIT)
Chain
Spreader
SLIDE CHAIN
SPREADER
ONTO RAIL
Alignment
Groove
Alignment
Groove