Tighten The Chain; Assembly; Installation - Chamberlain LiftMaster 3275C Owner's Manual

ASSEMBLY STEP 3

Tighten the Chain

• Spin the inner nut and lock washer down the trolley threaded
shaft, away from the trolley.
• To tighten the chain, turn outer nut in the direction shown
(Figure 1).
• When the chain is approximately 1/2" (13 mm) above the base
of the rail at its midpoint, re-tighten the inner nut to secure the
adjustment.
Sprocket noise can result if chain is too loose.
When installation is complete, you may notice some chain droop
with the door closed. This is normal. If the chain returns to the
position shown in Figure 2 when the door is open, do not
re-adjust the chain.
NOTE: During future maintenance, ALWAYS pull the emergency
release handle to disconnect trolley before adjusting chain. You
may notice loosening of chain after Adjustment Step 3 (Test the
Safety Reversal System). Check for proper tension and readjust
chain if necessary. Then repeat Adjustment Step 3.
You have now finished assembling your garage door opener.
Please read the following warnings before proceeding to the
installation section.

INSTALLATION

IMPORTANT INSTALLATION INSTRUCTIONS
To reduce the risk of SEVERE INJURY OR DEATH:
1. READ AND FOLLOW ALL INSTALLATION WARNINGS AND
INSTRUCTIONS.
2. Install garage door opener ONLY on properly balanced and
lubricated garage door. An improperly balanced door may not
reverse when required and could result in SEVERE INJURY
OR DEATH.
3. ALL repairs to cables, spring assemblies and other hardware
MUST be made by a trained door systems technician BEFORE
installing opener.
4. Disable ALL locks and remove ALL ropes connected to
garage door BEFORE installing opener to avoid entanglement.
5. Install garage door opener 7 feet (2.13 m) or more above
floor.
6. Mount emergency release handle 6 feet (1.83 m) above floor.
7. NEVER connect garage door opener to power source until
instructed to do so.
Figure 1
To Tighten Outer Nut
Trolley
Figure 2
WARNING
WARNING
WARNING WARNING
8. NEVER wear watches, rings or loose clothing while
installing or servicing opener. They could be caught in
garage door or opener mechanisms.
9. Install wall-mounted garage door control:
• within sight of the garage door.
• out of reach of children at minimum height of
5 feet (1.5 m).
• away from ALL moving parts of the door.
10. Place entrapment warning label on wall next to garage door
control.
11. Place manual release/safety reverse test label in plain view
on inside of garage door.
12. Upon completion of installation, test safety reversal system.
Door MUST reverse on contact with a 1-1/2" (3.8 cm) high
object (or a 2x4 laid flat) on the floor.
7
Lock
Washer
Outer Nut
Chain
1/2" (13 mm)
Base of Rail Mid Length of Rail
Inner Nut
To Tighten
Inner Nut