Chamberlain CG40DM - Manual (Page 14)

14
INSTALLATION STEP 3
Attach the Rail to the Header Bracket
1. Position the opener on the garage fl oor below the
header bracket. Use packing material as a protective
base.
NOTE: If the door spring is in the way you’ll need
help. Have someone hold the opener securely on a
temporary support to allow the rail to clear the spring.
2. Position the rail bracket against the header bracket.
3. Align the bracket holes and join with a clevis pin
5/16"x1-1/2" as shown.
4. Insert a ring fastener to secure.
ONE-PIECE DOOR WITHOUT TRACK
A 2x4 on its side is convenient for setting an ideal
door-to-rail distance.
1. Raise the opener onto a stepladder. You will need help
at this point if the ladder is not tall enough.
2. Open the door all the way and place a 2x4 on its side
on the top section of the door beneath the rail.
3. The top of the door should be level with the top of the
motor unit. Do not position the opener more than 4"
(10 cm) above this point.
INSTALLATION STEP 4
Position the Opener
Follow instructions which apply to your door type as
illustrated.
SECTIONAL DOOR OR ONE-PIECE DOOR WITH
TRACK
A 2x4 laid fl at is convenient for setting an ideal
door-to-rail distance.
1. Raise the opener onto a stepladder. You will need help
at this point if the ladder is not tall enough.
2. Open the door all the way and place a 2x4 laid fl at on
the top section beneath the rail.
3. If the top section or panel hits the trolley when you
raise the door, pull down on the trolley release arm
to disconnect inner and outer sections. Slide the outer
trolley toward the motor unit. The trolley can remain
disconnected until Installation Step 12 is completed.
RELEASED ENGAGED
Trolley
Release Arm
Clevis Pin 5/16"x1-1/2" Ring Fastener
To prevent damage to garage door, rest garage door
opener rail on 2x4 placed on top section of door.
Rail
Door
2x4 is used to determine
the correct mounting
height from ceiling.
Top of Door
2x4 is used to determine
the correct mounting
height from ceiling.
Header Bracket
INCREASE
TRA
VEL
DOWN
UP
Header Wall
Header Bracket
Idler Pulley
Header
Bracket
Ring
Fastener
Mounting
Hole
Clevis Pin
Opener Carton or
Temporary Support
Garage Door
HARDWARE SHOWN ACTUAL SIZE