The SV-12 is a Solenoid Operated Diesel Fuel Shutoff Valve for a 12 volt system. This model has a 1/4 NPT inlet and outlet, and a full 3/16 inch (5 mm) orifice. The SV valves open against 30 psi (207 kPa) [2.07 bar] inlet pressure. The SV-12 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.