Dears,
I am working in a process industry, I would like to know how to change over pilot operated pressure relief valve from one to another for hand over to maintenance. I am caught between experienced operators who say ( A and B PRV Valves ) initial A isolated and B in line - To start change over first open pilot A..then main A .. close main B then pilot B.
Some others say Open Main A, Open Pilot A, close pilot B then main B.
I am confused, i am aware of the working. Please guide.
Cheers
Franck.