Chamberlain 248735S 3/4 HP Garage Door Opener User Manual


 
9
To avoid SERIOUS damage to garage door opener,
use ONLY those bolts/fasteners mounted in the top of
the opener.
ASSEMBLY STEP 2
Fasten the Rail to the Motor Unit
Insert a 1/4"-20x2" bolt, washer and spacer into the
cover protection bolt hole on the back end of the rail
as shown. Tighten securely with a 1/4"-20 lock nut.
DO NOT overtighten.
Remove the bolt and lock nut from the top of the
motor unit.
Attach spreader to the motor unit with two screws.
Place the “U” bracket, fl at side down onto the bolt
mounted on the motor unit and align the bracket hole
with the bolt holes. Fasten with the previously removed
bolt and lock nut.
Align the rail assembly with the top of the motor unit.
Slide the rail end onto the “U” bracket, all the way to the
stops that protrude on the top and sides of the bracket.
ASSEMBLY STEP 3
Install the Idler Pulley
Lay the chain/cable beside the rail, as shown. Grasp
the end with the cable loop and pass approximately 12"
(30 cm) of cable through the window. Allow it to hang
until Assembly Step 5.
Remove the tape from the idler pulley. The inside center
should be pre-greased. If dry, regrease to ensure proper
operation.
Place the idler pulley into the window as shown.
Insert the idler bolt from the top through the rail
and pulley. Tighten with a 3/8" lock washer and nut
underneath the rail until the lock washer is compressed.
Rotate the pulley to be sure it spins freely.
Insert a 1/4"-20x1-3/4" bolt into the trolley stop hole in
the front of the rail as shown. Tighten securely with a
1/4"-20 lock nut.
HARDWARE SHOWN ACTUAL SIZE
HARDWARE SHOWN ACTUAL SIZE
Bolt
Hex Screws
8-32x7/16"
Chain Spreader
Motor Unit
Sprocket
“U” Bracket
Lock Nut
Lock Nut
Bolt
Spacer
Washer
SLIDE RAIL TO
STOPS ON TOP AND
SIDES OF BRACKET
Cover
Protection
Bolt Hole
Idler Bolt
Lock
Nut
Grease
Inside Pulley
Chain and Cable
Pulley
Bolt
Nut
Rail
Washer
Lock
Washer
3/8"
Screwdriver
Idler
Bolt
Cable Link
Idler
Pulley
Trolley
Stop Hole
Bolt
Idler
Pulley
Nut
3/8"
Nut 3/8"
Lock Nut 1/4"-20Lock Washer 3/8"
Bolt 1/4"-20x1-3/4"
Trolley
Washer 5/8"
Spacer
Lock Nut
1/4"-20
Bolt 1/4"-20x2"