Genie M-4500, M-4700 owner manual Tension Adjustment, Rail Length Adjustment

13. TENSION ADJUSTMENT

Your preassembled rail comes with the tension adjusted to factory specifications. There should be no need for further adjustment. However, if exposed or subjected to unusually harsh operating conditions, the tension may need to be readjusted during the life of the opener.

CHECK PROPER

TENSION (FIG. 52):

■Release trolley from belt or chain, then examine the set- ting of the tension adjustment at the header end of the rail.

■Proper tension is set when the tension nut is tightened just enough so that the washer will be spaced approxi- mately 1mm or 3/64" from the stationary rail end-stop arch.

■If the gap between the washer and the rail end-stop arch is too big or too small, the tension needs to be adjusted.

ADJUST THE TENSION:

■To increase the tension and tighten the belt or chain, turn the tension nut clockwise with 7/16” wrench until the washer is spaced properly from the rail end-stop arch. See Fig. 52.

■Once the washer is spaced correctly, any additional tightening will overtighten the belt or chain and may cause damage to the system.

■To loosen the tension, turn nut counterclockwise.

■Reattach trolley.

Fig. 52
	Proper Tension Adjustment
Rail End Stop	Tension	Washer	Roller Holder Assembly
(Header End)	Nut

Proper Space (1mm or approximately 3/64”)

14. RAIL LENGTH ADJUSTMENT

FOR PROFESSIONAL INSTALLERS ONLY

If your particular installation calls for a shorter rail than the standard length provided, it is possible to shorten the rail.

NOTE: Shortening rail too much may result in door travel length reduction and door not opening fully. This depends on door size and configuration. Carefully plan all such modifications before proceeding. THIS PROCEDURE SHOULD BE PERFORMED ONLY BY A PROFESSIONAL INSTALLER FULLY FAMILIAR WITH THIS TYPE OF OPENER SYSTEM.

TO SHORTEN BELT RAIL LENGTH:

■Loosen belt tension as much as possible.

■Remove screws from sprocket holder and rail end-stop.

■Slide belt and all rail parts out of rail from header end. See rail exploded view, Fig. 54 on p. 25, for disassembly details.

■Measure and cut off excess rail from header end.

■Disassemble connector to expose free ends of belt.

■Using the same measurement as the excess rail length, cut the same amount off BOTH free ends of the belt.

■Using rail end-stop as a guide, mark and drill two 3/16" holes on rail sides for rail end-stop screws.

■Reassemble belt connector, and slide all rail parts into rail from header end according to original assembly.

■Tension belt properly.

■Before installing rail overhead, check for proper assembly and operation by manually moving trolley up and down rail length with trolley connected to belt.

Fig. 53

1”	Chain Link
	Chain Strap

TO SHORTEN CHAIN RAIL LENGTH:

■Loosen chain tension as much as possible.

■Remove screws from sprocket holder and rail end-stop.

■Slide chain and all rail parts out of rail from header end. See rail exploded view, Fig. 55 on p. 25, for disassembly details.

■Measure and cut off excess rail from header end by 1” increment only.

■Disassemble connector to expose free ends of chain.

■Using the same measurement as the excess rail length, remove the same amount off chain links and chain straps from BOTH free ends of the chain (Fig. 53).

■Using rail end-stop as a guide, mark and drill two 3/16" holes on rail sides for rail end-stop screws.

■Reassemble two piece connector and slide chain and all rail parts into rail from header end according to original assembly.

■Tension chain properly (Fig. 52).

■Before installing rail overhead, check for proper assembly and operation by manually moving trolley up and down rail length with trolley connected to chain.

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