Assembly - Chamberlain HD420EVP Owner's Manual

Assembly

STEP 1 Assemble the rail and install the 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. The rail tab MUST be on 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. Align the rail sections on a flat surface as shown and 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 in the second rail section from the motor
unit, 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 rail onto the "U" bracket, until it reaches all the stops on the top and sides of the "U"
bracket.
Outer Trolley
Inner Trolley
Wear Pads
Rail Tab
Front Rail
Section
(TO DOOR)
5
SLIDE TO STOPS
ON TOP AND
SIDES OF
"U" BRACKET
"U" Bracket
To garage
door opener
(TO MOTOR UNIT)
Trolley