Section 3: Jackscrew Override; Jackscrew Operating Instructions; Actuator Stroke Adjustment; Models 006 Through 270 - Emerson Bettis M Series Installation, Operation And Maintenance Manual

Stainless steel scotch yoke actuators
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Section 3: Jackscrew Override

July 2019
Section 3: Jackscrew Override
The jackscrew option is intended for infrequent or emergency on-site operation of the
automated valve.
3.1

Jackscrew Operating Instructions

1.
2.
3.2

Actuator Stroke Adjustment

The jackscrew has a built-in actuator stroke adjustment, see Figure 2 and 3.
3.3

Models 006 through 270

See Figure 2:
1.
2.
3.
3.4
Models 370, 740 & 575
See Figure 3:
1.
2.
3.
4.
4
Disengage power supply and vent air from actuator.
Operate the handwheel to drive the actuator into the desired position. Valve
position can be verified by checking the actuator position indicator. For models
006 through 270, the jackscrew must be returned to the fully retracted position
before actuator can resume normal operation. Back the jackscrew out until it
stops. Air will leak from the jackscrew unless it has been fully retracted against its
internal seal.
Retract the jackscrew override completely by rotating counter clockwise.
Loosen the lock nut and turn the brass adjusting screw to the desired position.
The handwheel will rotate with the adjusting screw. Never make stroke
adjustments by turning the handwheel only.
Tighten lock nut.
Retract the jackscrew override completely by rotating clockwise.
Loosen the stroke adjusting screw and lock nut.
Using the handwheel, turn the jackscrew to adjust the actuator to the
desired position.
Screw the adjusting screw until it stops and tighten lock nut.
Installation, Operation and Maintenance Manual
MAN-02-01-39-0704-EN Rev. 0
Jackscrew Override

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