Chamberlain 8808CB - User Manual

Eight-Foot (2.4 m) Rail Extension Kit
Models 8808CB and 8808CB-P
To prevent possible SERIOUS INJURY or DEATH:
• Disconnect ALL electric and battery power BEFORE performing
ANY service or maintenance.
The garage door MUST be in the fully closed position during
installation.
WARNING: This product can expose you to chemicals including
lead, which are known to the State of California to cause
cancer or birth defects or other reproductive harm. For more
information go to www.P65Warnings.ca.gov
Figure 2
To remove rail pry both
end tabs of front
rail slightly outward
Idler Bolt hole
(KEEP LARGER
ONE ON TOP)
NEW
FRONT RAIL
CORRECT
INCORRECT
Rail Tab
Rail Tab
BEFORE YOU BEGIN:
• The trolley must be in down (closed door) position during assembly
and installation. If you have a completely installed garage door opener,
the rail/opener assembly must be taken down. UP and DOWN Limits must
be readjusted after installation.
• Opener hanging brackets will require repositioning and the addition of an
extra bracket for stability due to increased rail length.
IF THIS IS A NEW INSTALLATION:
Use the front (header) rail section, belt assembly, and longer emergency
release rope in this kit in place of those packaged with your garage door
opener. Complete the assembly, installation,and adjustment of your opener
according to your owner’s manual,with the exception of adding an
additional hanging bracket for stability.
IF THIS IS AN EXISTING INSTALLATION, CONTINUE AS FOLLOWS:
1. Pull down on the emergency release handle, then disconnect the trolley
from the door arm.
2. Disconnect the rail/opener assembly from the header bracket and
hanging brackets, and place it on the floor.
3. Remove the belt cap retainer from the opener sprocket and set aside.
4. Disconnect the master link from the trolley threaded shaft and belt;
discard (Figure 1).
5. Remove the spring/nut from the trolley and discard.
6. Remove idler pulley assembly and set aside.
7. Remove the belt assembly and discard.
8. Push the trolley back toward the opener. Disconnect the front rail
section by using a screwdriver tip to pry up the outer tab on each side
of the rail, then slide it off the center rail. Discard the front rail (Figure
2).
9. Align the new front rail with the existing rail assembly, keeping the cut
out “window” at the front (header) end. Be sure to keep it right side up:
the idler pulley bolt hole above the window is larger on top of the rail
than on the bottom. Slide the front rail onto the assembly; tabs along
the side will lock into place.
10. As a temporary stop, insert a screwdriver into the hole 10" (25 cm)
from the front end of the rail (Figure 1). Slide the trolley assembly to
this point.
11. Lay the new belt beside the rail. Grasp the end with the hooked trolley
connector and pass approximately 12" (30 cm) of belt through the
window. Keeping the ribbed side toward the rail, and allow it to hang
while you complete the next two steps.
12. Replace the idler pulley, lock washer and nut. Rotate it to be sure it
spins freely. Grease the center if necessary.
13. Locate the rail tab. Use a flathead screwdriver and lift the rail tab until
the tab is vertical (90°) (Figure 2).
14. Pull the belt around the idler pulley and hook the trolley connector into
the retaining slot on the trolley (Figure 1). The ribbed side must
contact the pulley.
15. With the trolley against the screwdriver, dispense the remainder of the
belt along the rail length toward the motor unit and around the
sprocket (Figure 1). The sprocket teeth must engage the belt.
16. Check to make sure the belt is not twisted, then connect it to the flat
end of the trolley threaded shaft with the master link (Figure 1):
• 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.
Figure 1
Master
Link
Trolley
Connector
Retaining
Slot
Threaded
Shaft
Front Rail
Section
Master
Link
Idler Pulley
Retaining
Slot
Trolley
Connector

Summary

General Safety and Warnings

Prevent Serious Injury or Death

Disconnect all electric and battery power before performing any service or maintenance.

Installation Caution

The garage door must be in the fully closed position during installation.

California Proposition 65 Warning

Product may expose you to chemicals like lead, known to cause cancer or birth defects.

Existing Installation Procedure

Disconnect Trolley and Rail Assembly

Disconnect trolley from door arm and rail/opener assembly from brackets.

Replace Front Rail Section

Remove old front rail section and attach new front rail, ensuring correct alignment.

Install Belt and Idler Pulley

Thread belt, connect trolley connector, install idler pulley, and ensure proper belt contact.

Secure Belt with Master Link

Connect belt to trolley threaded shaft using master link, ensuring secure locking.

Set Belt Tension

Tighten spring trolley nut to set optimum belt tension by releasing and snapping the nut ring.

Final Steps and Testing

Replace belt cap retainer, reconnect power, and test safety reversal system.

Adding an Additional Hanging Bracket

Bracket Installation

Fasten the cross brace to hanging brackets using hex bolts, lock washers, and nuts.

Masonry Installation Note

Concrete anchors must be used if installing any brackets into masonry.

Chamberlain 8808CB Specifications

General

Type	Chain Drive
Horsepower	1/2 HP
Max Door Height	7 ft
Battery Backup	No
Speed	7 inches per second
Motor	DC Motor
Remote Controls Included	2
Smart Technology	Yes
Security	Rolling Code