pressure fall below pilot setting, the pilot releases accumulated pressure causing the main valve to modulate open. should the solenoid close, pressure in the upper control chamber accumulates causing the main valve to shut off. normally closed, normally open and last position models are available. the needle...
accumulated pressure to the main valve outlet through the held open pr pilot [ ] causing the main valve to modulate open. should opening the main valve cause downstream pressure to rise above pr pilot setting, the pilot closes, causing the main valve to throttle closed, reducing downstream pressure. the needle...