Hello
We faced a problem with one of our rotary SIS valve when a poisoner toke the valve toward faille plosion for 3 min then opened again by itself without a change in command signal. When maintenance team attend the valve they notice air is bleeding in pulses manner. There was no alert triggered beside travel deviation alarm.
due to the criticality of the valve The poisoner then replaced with 6200sis.
The poisoner then put in a bench on a test valve and same scenario happen air start bleeding in pulses manner no alert triggered, after I/P and Relay replaced the bleeding stopped.
our PM include a visual check for the valve and poisoner components. but the PM intervals varies from valve to valve it could be as short as 1 month to 6 years.
Our question how to prevent that from reoccurrence to the rest of the valves?
Thank you in advance.