Chamberlain 248754 - Manual (Page 8)

FRONT RAIL
(TOP)
KEEP LARGER
HOLE ON TOP
8
ASSEMBLY STEP 1
Assemble the Rail and Install the
Trolley
To avoid installation difficulties, do not run the
garage door opener until instructed to do so.
Front Rail
(TO DOOR)
Window
Cut-Out
Screwdriver
Idler
Pulley
Hole
Tabs
Back Rails
(TO MOTOR UNIT)
Trolley
Tapered
End
Tapered
End
Inner Trolley
Wear Pads
Outer Trolley
Tapered
End
Tapered
End
To prevent INJURY from pinching, keep hands and fingers
away from the joints while assembling the rail.
The front rail has a cut out “window” at the door end
(see illustration). The hole above this window is larger
on the top of the rail than on the bottom. A smaller hole
3-1/2" (8.9 cm) away is close to the rail edge. Rotate the
back rail so it has a similar hole close to the opposite
edge, about 4-3/4" (12 cm) from the far end.
1. Remove the straight door arm and hanging bracket
packaged inside the front rail and set aside for
Installation Step 5 and 12. 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
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 along the rail from the back
end to the screwdriver.