... ways normal closed solenoid valve with diaphragms can be widely used in refrigeration, pneumatic and hydraulic system, ... also in boiler and fire-fighting, etc.Solenoid valves use ... orifice. Then the pressure in upside of valve reduced, so the pressure difference between both ... 507,air,water and oil.Optional voltage of solenoid coils: A.C.: 24V,36V,110V, ...