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Instruction Manual
D100291X012
1. Bypass the valve body or shut off the pressure in the pipeline.
CAUTION
The adjustable linkage between the actuator and the main valve should not be disconnected when the valve is open with
fluid flowing. (Dampers or louvers should be in safe, stable positions prior to disconnection.)
2. Shut off all pressure to the actuator. Remove all tubing lines (cylinder, instrument, and supply) from the actuator.
3. Remove the positioner cover after loosening the four cover screws on the underside of the positioner base.
4. Disengage the range spring by unscrewing the spring retainer from the piston rod extension.
5. Loosen the two cap screws that hold the positioner to the cylinder. When removing the positioner, do not lose the
small O-ring that is used in the passage from the positioner to the top of the cylinder.
6. Next remove the clevis bolt from the adjustable linkage. Remove the bottom snap ring (key 26) and unscrew the
clevis and the boot locknut from the actuator piston rod.
7. Remove the nuts that hold the cylinder to the mounting flange and lift off the cylinder.
8. Remove the stud bolts (key 123) that hold the cylinder to the cylinder flange. Two slots, 180 degrees apart, are
located at the lower edge of the cylinder. Insert a screwdriver in these slots and pry the cylinder loose. The piston
and piston rod will come out with the cylinder. the piston can then be removed by pulling it out the open end of the
cylinder.
9. Unscrew both seal bushings (keys 7 and 8).
10. Inspect all parts for excessive wear and defects. Replace all worn O-rings. Lubricate as mentioned above.
11. To reassemble, reverse the above procedure.
Note
When reassembling the actuator after the piston rod extension (key 5) has been removed from the piston rod (key 4), clean the
threads of the piston rod thoroughly and apply a thread locking adhesive (medium strength) to the threads. Tighten the piston rod
extension securely to a torque of 203 NSm (150 lbfSft). This torque is approximately equal to the torque that would be developed
by placing a force of 150 pounds on the end of a one-foot wrench, 75 pounds on the end of a two-foot wrench, etc.
480 Series Actuators
August 2012
9
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