Chamberlain LiftMaster PROFESSIONAL SECURITY+ 1265LMC Manuel Du Propriétaire page 7

ASSEMBLY STEP 3
Tighten the Chain
• Spin the inner nut and lock washer down the
threaded shaft, away from the trolley.
• To tighten the chain, turn outer nut in the direction
shown. As you turn the nut, keep the chain from
twisting.
• When the chain is approximately 1/2" above the
base of the T-rail at its midpoint, re-tighten the inner
nut to secure the adjustment.
Sprocket noise can result if chain is either too
loose or too tight.
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 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 have now finished assembling your garage
door opener. Please read the following warnings
before proceeding to the installation section.
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 or more above floor.
6. Mount emergency release handle 6 feet above floor.
7. NEVER connect garage door opener to power source
until instructed to do so.
To Tighten Outer Nut
Trolley
WARNING
CAUTION
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
• 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 one-
inch high object (or a 2x4 laid flat) on the floor.
7
Lock
Washer
Outer Nut
Inner Nut
To Tighten
Inner Nut
Chain
1/2 Inch
Base of T-rail
WA
WA