I need to pull open an oil separator located in the discharge line of a supermarket rack system to check the mesh screen and buoy mechanism. In order to isolate the separator, upstream I can shut all of the compressor´s discharge service valves. But downstream the separator there is no service shut-off valve but rather a differential discharge pressure regulator. It´s my understanding that this regulator, when energized, remains 100% open. When de-energized, it begins to close but never to a full shut-off. Is it possible to somehow completely close this regulator when the system is off, in order to isolate the separator from the condenser inlet? Thank you.