Chamberlain LiftMaster PROFESSIONAL SECURITY+ 3255-2CM Manuel Du Propriétaire page 7

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