Chamberlain WHISPER DRIVE WD912K - Manual (Page 8)

8
ASSEMBLY STEP 1
Assemble the Rail and
Attach the Belt Pulley Bracket
To avoid installation difficulties, do not run the
garage door opener until instructed to do so.
1. Align the four rail sections on a flat surface exactly
as shown. Center sections are interchangeable.
Front and back sections are also interchangeable
for ease of assembly.
2. Insert the carriage bolts so the square
bolt necks seat in the square holes in
the rail sections and pass through the
round holes in the rail braces. Make
sure bolt necks are seated in the
square holes and rails are aligned
before you tighten lock nuts.
Improper assembly can cause jerky
trolley operation, noise and/or
nuisance door reversals.
3. Assemble lock nuts, ensure alignment
and tighten.
NOTE: If rail is not assembled exactly as shown,
trolley will not travel smoothly along length of rail
or it will hit against nuts.
4. Position the belt pulley bracket on the front end of
the rail as shown. Fasten securely with the
hardware shown.
NOTE: When tightening the bolts, be sure to keep
bracket parallel to the rail. Otherwise, the rail may
bow when the opener is operated.
RAIL BACK
(TO MOTOR UNIT)
RAIL FRONT
(TO DOOR)
Belt pulley bracket
attaches to FRONT
END of Rail
Rail
(End Section)
Rail
(Center Section)
Carriage Bolt
1/4"-20x1/2"
Rail
(End Section)
Square Carriage
Bolt Hole
Lock Nut 1/4"
Hex Bolts
5/16"-18x7/8"
Belt Pulley
Bracket
Bracket & Rail Must Be Aligned
Lock Washer
5/16"
Nut
5/16"-18
Lock Nut
1/4"-20 Carriage Bolts
1/4"-20x1/2"
Hex Bolt
5/16"-18x7/8" Nut
5/16"-18 Lock Washer
5/16"
HARDWARE SHOWN ACTUAL SIZE