lift-master 2280 User 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.

To avoid SERIOUS damage to opener, ONLY use
bolts/fasteners mounted in top of motor unit.

WARNING

CAUTION

WARNING

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
Threaded
Shaft

Spring/Trolley Nut

Nut
Ring

Trolley
Threaded
Shaft

Nut Ring
Slots

Square
End

Nut Ring

Trolley

Nut Ring

Trolley

1" (2.5 cm)

1-1/4" (3.18 cm)

BEFORE

AFTER RELEASE

Figure 1

Figure 2

Figure 3

USE ONLY THIS

TYPE AND SIZE

BOLT

Washered Bolt
5/16"-18x1/2"

Rail
Hole

Sprocket

Rail
Hole