A typical motor-operated valve has been returned to service following a complete maintenance overhaul of the valve and actuator.
The valve was remotely opened and closed to verify operability.
The measured valve stroke time in each direction was 15 seconds, which is 25 percent longer than normal.
Which one of the following could have caused the increased stroke time?
A. The valve position limit switches were removed and were not reinstalled.
B. The valve torque limit switches were misadjusted to open at half their normal setpoints.
C. The valve was packed with improved packing material having a lower friction coefficient.
D. The valve stem packing gland was overtightened after the packing material was replaced.
Show Answer
Answer: D
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