Chamberlain 2580 1/2 HP - Manual (Page 6)

6
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 bolts 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.
To avoid SERIOUS damage to opener, ONLY use bolts
mounted in top of motor unit.
WARNING
CAUTION WARNING
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.
Styrofoam
Belt
T-Rail
Hole
Washered Bolt
5/16"-18x1/2"
Washered Bolt
5/16"-18x1/2"
T-Rail
Hole
Motor unit
Sprocket
T-Rail
Hole
USE ONLY THIS
TYPE AND SIZE
BOLT
Trolley
Threaded
Shaft
Spring/Trolley Nut
Nut
Ring
Trolley
Threaded
Shaft
Nut Ring
Slots
Square
End
Nut Ring Trolley Nut Ring Trolley
1" 1-1/4"
BEFORE AFTER RELEASE
Figure 1
Figure 2
Figure 3