Tightenthe Chain; Installation - Craftsman 139.53920DM Owner's Manual

ASSEMBLY STEP 5
Tightenthe Chain
• Spin the innernut 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 1/4" (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 puff the emergency
release handle to disconnect trofley before adjusting chain. You
may notice loosening of chain after Adjustment Step 3 (Test the
Safety ReversalSystem). Check for proper tension and readjust
chain if necessary. ThenrepeatAdjustment Step 3.
Youhave now finished assemblingyour garage door opener.
Please read the following warningsbeforeproceedingto the
installation section.
Figure1
Figure 2
Trolley
Outer Lock Threaded
Nut Washer Shaft
To Tighten Outer Nut
Inner Nut
To Tighten
Inner Nut
I
Chain
Base Rail
1/4" (6 mm)
Mid length of Rail
INSTALLATION
IMPORTANTINSTALLATION INSTRUCTIONS
To reduce the riskofSEVERE INJURY or DEATH:
1. READAND FOLLOWALL INSTALLATION WARNINGSAND
INSTRUCTIONS.
2. Install garage door opener ONLYon properly balanced and
lubricated garage door. An improperly balanceddoor may
NOT reverse when required and could result in SEVERE
INJURYor DEATH.
3. ALL repairs to cables, spring assemblies and other hardware
MUST be made by a trained door systems technician BEFORE
installing opener.
4. DisableALL 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 the emergency releasewithin reach, but at least 6 feet
(1.8 m) above the floor and avoiding contact with vehicles to
avoid accidental release.
7. NEVERconnect 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. Placeentrapment warning label on wall next to garage door
control.
11. Placemanual release/safetyreverse 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.
11