Assembly - Chamberlain HD920EV Owner's Manual

Assembly

STEP 5 Tighten the belt and install the sprocket cover
To avoid possible SERIOUS INJURY to finger from moving garage door opener:
• ALWAYS keep hand clear of sprocket while operating opener.
• Securely attach sprocket cover BEFORE operating.
1. Spin the inner nut and lock washer down the trolley threaded shaft, away from the trolley
2. To tighten the belt, turn outer nut in the direction shown until the line on the spring retainer
plate is visible. Be sure the belt is not twisted, and the ribbed side faces the rail.
3. Tighten the inner nut to secure the adjustment. This sets the spring to optimum belt tension.
4. Position the sprocket cover over the sprocket as shown and fasten to the mounting plate with
8x3/8" hex screws provided.
You have now finished assembling your garage door opener. Please read the following warnings
before proceeding to the installation section.
HARDWARE
Hex Screw #8x3/8"
(Packed with the
sprocket cover)
CORRECT
INCORRECT
9
Outer Nut Spring Retainer
Inner Nut
Lock Washer
Line
Line
Hex Screw #8x3/8"
Sprocket Cover