Assembly; Attach The Rail To The Motor Unit; Set The Belt Tension - Chamberlain 2280-267 Owner's Manual

ASSEMBLY STEP 1

Attach the Rail to the Motor Unit

To avoid installation difficulties, do not run the
garage door opener until instructed to do so.
• Remove the two washered bolts mounted in top of
motor unit.
• Align rail and styrofoam over sprocket. Cut tape
from rail, belt and styrofoam.
• REMOVE STYROFOAM.
• Insert washered bolts through the rail into the
motor unit. Tighten bolts securely.
Use only these bolts! Use of any other bolts
will cause serious damage to door opener.
• Position belt over the motor unit sprocket.
ASSEMBLY STEP 2

Set the Belt Tension

• By hand, thread the spring trolley nut on the
threaded shaft until it is finger tight against the
trolley (Figure 1). Do not use any tools.
• Insert a screwdriver tip into one of the nut ring
slots and brace it firmly against the trolley
(Figure 2).
• Place a 7/16" open end wrench on the square
end. Rotate about 1/4 turn until the spring releases
and snaps the nut ring against the trolley
(Figure 3).
This extends the spring for optimum belt tension.
Trolley Nut Ring
BEFORE
1" (2.5 cm)
Figure 3
Trolley Nut Ring
AFTER RELEASE
1-1/4" (3.18 cm)
WARNING
CAUTION
To avoid SERIOUS damage to opener, ONLY use
bolts/fasteners mounted in top of motor unit.
USE ONLY THIS
TYPE AND SIZE
BOLT
Spring/Trolley Nut
Figure 1
Figure 2
6
Trolley
Threaded
Shaft
Trolley
Threaded
Shaft
Nut
Ring
Square
End
Nut Ring
Slots