The SV-series valve is a normally closed valve that opens when current is supplied from the battery through a magnetic switch. Temperature, level, or pressure SWICHGAGE® instruments installed on the engine and pump or compressor, trip the magnetic switch, breaking the circuit from the battery which closes the valve and stops the engine. The SV-12 valve operates on 12VDC, has a 1/4 NPT inlet and outlet, and a full 3/16 in. (5 mm) orifice. 24 VDC (SV-24) is optional The SV valves open against 30 psi. (207 kPa) [2.07 bar] inlet pressure.