Manual Valve (HV)
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Guys, I’d like to know how to determine which valves are manual valves and drain valves when looking at PID diagrams Thank you!
First, look at the legend; it specifies the symbols for control valves and manual valves. As for the drain valve, one needs to make a judgment on their own – generally, if it is oriented downward and located at the inlet or outlet of the pump, or at the bottom of the static equipment, then it is likely a drain valve
The legend does not specify the symbol for manual valves, and no relevant regulations could be found on Baidu; therefore, I am seeking help
Then check whether there is a control signal input to the valve; if not, it is a manual valve. Alternatively, check if the valve has a tag number – valves that are controlled remotely definitely have a tag number
Just look at the graphic explanation on the home page
Most manual valves are not labeled with their position numbers; there are too many of them – for a single pump, there are no fewer than four manual valves involved