Chamberlain C2102 Installation Manual page 11

Assembly
STEP 5 Tighten the Chain
1. Spin the inner nut and lock washer down the trolley threaded shaft, away from the trolley.
2. To tighten the chain, turn the outer nut in the direction shown.
3. When the chain is approximately 1/4" (6 mm) above the base of the rail at it's midpoint, retighten the
inner nut to secure the adjustment.
Sprocket noise can result if the 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 when the door is open,
do not re-adjust the chain.
NOTE: During future maintenance, ALWAYS pull the emergency release handle to disconnect the trolley before
adjusting the chain.
You have now finished assembling your garage door opener. Please read the following warnings before
proceeding to the installation section.
To Tighten Outer Nut
Chain
Base of Rail
Trolley
Lock
Outer
Threaded
Nut Washer
Shaft
Inner Nut
To Tighten
Inner Nut
1/4" (6 mm)
Mid length of Rail
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