GA diaphragm actuated pressure relief/sustaining valves are used to protect systems from excessive overpressure or to sustain a minimum upstream pressure. The valve’s pilot system senses the upstream (inlet) pressure. As long as the upstream pressure is below the setting of the valve’s pilot the main valve is tightly closed. When the inlet pressure rises above the setting of the valve’s pilot opens the main valve to allow flow into the downstream system (sustaining application) or to allow excess pressure to be discharged out of the system (relief application). GA diaphragm actuated relief/sustaining valves can be supplied with solenoid shutoff and/or check function as well as other optional features. See individual Data Sheets for details.