Valve is normally closed. When energised, the pressure decomposes on the secondary side of the diaphragm. Then the pressure differential (delta p) lifts the diaphragm from the seat (orifice). These valves are used where a flow producing a minimum pressure drop is always present in a system or in systems where the valves full flow capacity is not required under low flow conditions. Solenoid cast resin encapsulated with 3m cable ends.