Chamberlain WHISPER DRIVE 248754 - Manual (Page 10)

10
ASSEMBLY STEP 4
Install the Belt and Attach the Belt Cap
Retainer
1. Pull the belt around the idler pulley and toward the
trolley. The ribbed side must contact the pulley.
2. Hook the trolley connector into the retaining slot on the
trolley as shown.
3. With the trolley against the screwdriver, dispense the
remainder of the belt along the rail length toward the
motor unit and around the belt pulley. The belt pulley
teeth must engage the belt.
4. Check to make sure the belt is not twisted. Connect
the trolley threaded shaft with the master link, as
illustrated:
• Push pins of master link bar through holes in end of
belt and trolley threaded shaft.
• Push master link cap over pins and past pin notches.
• Slide clip-on spring over cap and onto pin notches
until both pins are securely locked in place.
5. Insert the trolley threaded shaft through the hole in the
trolley. Be sure the belt is not twisted.
6. Hold the belt at the trolley shaft as you thread the
spring nut by hand onto the shaft until fi nger tight
against the trolley. DO NOT use any tools.
7. Remove the screwdriver.
8. Position the belt cap retainer over the motor unit belt
pulley as shown and fasten to the mounting plate with
8x3/8" hex screws provided.
To avoid possible SERIOUS INJURY to fi ngers from
moving garage door opener:
• ALWAYS keep hand clear of belt pulley while
operating opener.
• Securely attach belt pulley cover BEFORE operating.
HARDWARE SHOWN ACTUAL SIZE
Spring/Trolley Nut (1)
Hex Screw 8x3/8"
Motor Unit
Belt Pulley
Belt Cap
Retainer
Mounting
Plate
8x3/8" Hex Screws
Spring Nut
Master Link
Clip-On Spring
Master Link Cap
Master
Link Bar
Pin
Notch
Trolley
Threaded
Shaft
Hole
Retaining
Slot
Trolley
Connector
Idler
Pulley