Chamberlain 2580C 1/2 HP Attach the T-Railto the Motor Unit, Set the Belt Tension, ASSEMBLY STEP, ASSEMBLY STEP

ASSEMBLY STEP 1

Attach the T-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 T-rail and styrofoam over sprocket. Cut tape from T-rail, chain and styrofoam.

•REMOVE STYROFOAM.

•Insert both washered bolt through the T-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.

CAUTION

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

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

USE ONLY THIS

TYPE AND SIZE

BOLT

Belt
T-Rail
Hole
Washered Bolt	Motor unit
5/16"-18x1/2"	Sprocket

T-Rail

Hole

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 Trolley Nut Ring

BEFORE		AFTER RELEASE
	1"		1-1/4"

Figure 3

T-Rail

Hole

Trolley

Threaded

Shaft

Spring/Trolley Nut

Figure 1

Trolley

Threaded

Shaft

Nut

Ring

Square

End

Nut Ring

Slots

Figure 2

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