Craftsman 139.53978SRT owner manual Tighten Chain, = Lo Tro,.y

Assembly	Step 5	I
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 notre-adjust the chain.

NOT_. During future maintenance, AL WA YS pull the emergency release handle to disconnect trolley 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 ff necessary. Then repeat Adjustment Step 4.

Figure I o=_ Lo_ Tro,.y

Nut Washer Shaft

ToT_.,_nOuterNut.--_ I ! /

Inner Nut

Figure 2

Chain	I
r
--..L..L .LLLJ_	J--L_--L L_L_J_ _
	i	I1/_ Inch
	I
Base o Ra	Mid tength of Rail

You have now finished assembling your garage door opener. Please read the following warnings before proceeding to the installation section:

IMPORTANT INSTALLATION INSTRUCTIONS

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 flat 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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