Craftsman 139.53975SRT - Manual (Page 11)

Assembly Step 5
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 (Figure 1).
• When the chain is approximately 1/2" 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 troliey before
adjusting chain.
NOTE: You may notice loosening of chain after
Adjustment Step 4 (Test the Safety Reverse System).
Check for proper tension and readjust chain if
necessary. Then repeat Adjustment Step 4.
Figure 1
Outer Lock Trolley
Nut Washer Shaft
Base of Rail Mid length of Rail
You have now finished assembling your garage door opener. Please read the following
warnings before proceeding with installation.
IMPORTANT INSTALLATION INSTRUCTIONS
Л WARNING Д WARNING
To reduce the risk of severe injury or death to persons:
1. READ AND FOLLOW ALL INSTALLATION INSTRUCTIONS.
2. Install only on a properly balanced and lubricated garage door. An improperly balanced door
may not reverse and could result in severe injury or death. Repairs to cables, spring assemblies
and other hardware must be made by a professional service person before installing opener.
3. Disable all locks and remove all ropes connected to the garage door before installing the opener.
Ropes connected to a garage door can cause entanglement and death.
4. If possible, install door opener 7 feet or more above floor with the emergency release handle
mounted 6 feet above the floor.
5. Do not connect the opener to power source until instructed to do so.
6. Locate the Door Control within sight of the door at a minimum height of 5 feet where small
children cannot reach, and away from all moving parts of the door.
7. Install the User Safety Instruction Label on the wall adjacent to the door control and the
Maintenance Instruction Label in a prominent location on the inside of the garage door.
8. Upon completion of the installation, the door must reverse when it comes in contact with a
one-inch high object or a 2x4 laid fiat on the floor.
9. Do not wear watches, rings or loose clothing while installing or servicing an opener. Jewelry or
loose clothing can be caught in the mechanism of the garage door or the opener.
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