Fasten Rail To Motor Unit And Install The Trolley - Chamberlain Power Drive PD420 Owner's Manual

ASSEMBLY STEP 2
Fasten the Rail To the Motor Unit
and Install the Trolley
To aid in assembly and installation, replace the foam
packing around the motor unit. Remove it after Installation
Step 5.
• Working on a level surface, align the rail assembly with
the motor unit, as shown.
• Slip the coupling over the rail sprocket.
• Slide the rail through the motor unit bracket until the
coupling fits securely over the motor unit sprocket.
• Align the two screw holes in the rail with those in the
motor unit bracket. Insert two 1/4"-20x5/8" hex screws
and lock nuts. Tighten securely with a 7/16" socket
wrench.
• Slide the trolley onto and along the bottom of the rail
until it snaps firmly in place. Be certain to install it
facing correctly: the trolley release arm must be
horizontal (lock position), with its arrow pointed
away from the motor unit.
Rail
Assembly
Trolley
Release arm
Lock Nuts
1/4"-20
Coupling
Rail
Sprocket
Foam Packaging
Arrow must point
toward garage door
10
HARDWARE SHOWN ACTUAL SIZE
1/4" - 20
1/4" - 20 x 5/8" Lock Nut
Hex Screw
Motor Unit
Sprocket
Motor Unit
Bracket
Hex Screws
1/4"-20x5/8"