... 220V, pressurized valve and un-pressurized valve are available for selection, 9. operation pressure of pressurized valve: 0.02Mpa ~ 0.8Mpa, ... suitable for providing water directly operation pressure of un-pressurized valve: 0.0Mpa, 10. ... water circulation 15,Hot water pipe insulation 16,Low pressure protection 17,Collector tube protection 18,Memory protection when ...