Troubleshooting, Worcester controls – Flowserve PM15 Pneumatic Valve Positioner User Manual
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PM15 Pneumatic Valve Positioner Installation, Operation and Maintenance Instructions
WCAIM2016
E. LOWER ARM
Once the front cover is removed, the lower arm can be easily
accessed. Remove the indicator, feedback spring and the cam.
Loosen screw (2) and remove twist stop (1). Remove screw (3),
lower arm (4), rod (5) and spring (6).
Check rod and lower arm for wear, replace if necessary. Clean the
rod and install it in the lower arm. The lower arm should move
easily and smoothly.
Install the lower arm and rod assembly into the positioner
housing, making sure that the spring (6) is attached properly to
the lower arm and positioner housing.
Secure the lower arm and rod assembly with the screw (3). Check
again that the lower arm moves smoothly.
Apply a small amount of grease on the small tongue on the lower
arm, then install and secure the twist stop.
Install cam, feedback spring, indicator and front cover.
F. O-RINGS
With time and use, O-rings can become brittle. This can cause
poor operation and even failure of the positioner.
Always check O-rings when performing any work on the
positioner and replace bad O-rings.
A thin layer of silicon grease applied on the Buna N (Black) O-
rings prolongs their life. On Q (Red Silicon) O-rings, use a
non-silicon based grease.
9. TROUBLESHOOTING
NOTE: All PM15 positioners are serialized and date coded. Please note
and provide the serial number when contacting the factory for
troubleshooting or service.
Signal change results in actuator running to end positions:
•
Check coupling between positioner and actuator.
•
Check cam position and locking screw.
•
Check input signal.
Signal change has no effect on the actuator position:
•
Check indicator and screw.
•
Check air supply to positioner and tubing to the actuator.
•
Check input signal to positioner.
•
Check diaphragm for damage or leakage.
•
Check pilot valve function.
•
Check cam for correct setting.
Inaccurate positioning:
•
Dirty or worn pilot valve.
•
Defective or leaking diaphragm.
•
Input signal fluctuates.
•
Incorrect sizing of actuator.
•
Valve/actuator “stiction”.
•
High valve/actuator breakaway torque.
•
Loose cam.
Flow Control Division
Worcester Controls
Maintenance — Balance Arm
Maintenance — Lower Arm
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