Chamberlain CG40DM - Manual (Page 11)

11
INSTALLATION
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 outer nut in the direction
shown (Figure 1).
3. When the chain is approximately 1/4" (6 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 fi nished assembling your garage door
opener. Please read the following warnings before
proceeding to the installation section.
Figure 1
Figure 2
Trolley
Threaded
Shaft Lock
Washer
Outer
Nut
To Tighten
Inner Nut
Inner Nut
1/4" (6 mm)
Chain
Mid length of Rail
To Tighten Outer Nut
Base of Rail
IMPORTANT INSTALLATION INSTRUCTIONS
To reduce the risk of SEVERE INJURY or DEATH:
WARNING
WARNING
WARNING WARNING
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 fl oor.
6. Mount the emergency release within reach, but at least
6 feet (1.83 m) above the fl oor and avoiding contact
with vehicles to avoid accidental release.
7. NEVER connect garage door opener to power source
until instructed to do so.
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 fl at) on
the fl oor.