Craftsman 1/2HP Garage Door Opener 139.53515SR - Manual (Page 9)

Assembly
STEP 5
Tighten the Chain and Cable
1/2 Inch
CAUTION: Keep the chain fivm twisting as nute are
turned.
PROCEDURE: Thread the inner nut on the trolley in the
direction shown.
Tension is correct when the chain is approximately 1/2*
above the base of the Tee rail midway between the cable
pulley bracket and the opener.
To maintain proper tension, tighten outer nut as shown.
Sprocket noise can result if chain is either too loose
or too tight.
CAUTION: Do not overtighten the chain. Refer to
Page 3.
Bdsd of Too Roil
ASSEMBLY OF YOUR GARAGE DOOR OPENER IS NOW COMPLETE.
BEFORE YOU PROCEED WITH THE INSTALLATION OF YOUR GARAGE DOOR OPENER, BE SURE TO COMPLY WITH
ALL SAFETY RULES.
A
KEEP GARAGE DOOR BALANCED. STICKING OR BINDING DOORS MUST BE REPAIRED. THE GARAGE DOOR,
DOOR SPRINGS, CABLES, PULLEYS, BRACKETS AND THEIR HARDWARE ARE UNDER EXTREME TENSION
AND CAN CAUSE SERIOUS PERSONAL INJURY. DO NOT ATTEMPT TO LOOSEN, MOVE OR ADJUST THEM.
CALL A GARAGE DOOR SERVICEMAN.
DO NOT WEAR WATCHES, RINGS OR LOOSE CLOTHING WHILE INSTALLING OR SERVIONG A DOOR OPENER.
AS YOU PROCEED WITH THE REMAINING INSTRUCTIONS IN THIS OWNERS MANUAL, YOU MAY FIND IT HELPFUL
TO REFER TO THE FOLLOWING ILLUSTRATION OF THE FULLY ASSEMBLED AND INSTALLED GARAGE DOOR OPENER.
IT IS RECOMMENDED THAT THE OPENER BE INSTALLED 7 FEET OR MORE ABOVE FLOOR WHERE SPACE PERMITS.
CERTAIN INSTALLATION PROCEDURES VARY ACCORDING TO GARAGE DOOR TYPES. WHERE THE DIFFERENCES
OCCUR, BE SURE TO FOLLOW ONLY THOSE INSTRUCTIONS WHICH APPLY TO YOUR DOOR CONSTRUCTION.