The Viking Model C-1 Pressure Operated Relief Valve (PORV) is used in Viking Deluge Systems when automatically resetting releases are used. Once tripped, it maintains a positive vent to prevent the deluge valve from automatically resetting prematurely. The device is automatically reset when the pressure is removed from the control diaphragm. The device is designed to trip when approximately 5 psi (.3 bar) of pressure is applied to the control diaphragm. The trip point is non-adjustable. The PORV may also be used to trip the deluge valve by applying air or water pressure to the PORV control diaphragm. The PORV is shipped with Viking Conventional Deluge Valve trim.