Safe daily hot water that is succefully seperated from water heated by refrigerant ... . Polyurehane foam insulation3. 100L,200L,300L,400L,500L4. Optional electric heater and thermostat :3KW,6KW,9KW5. All inner tank is made ... steel outer case. HISEER stainless steel boiler, CE certification, Domestic Hot Water Tank with copper or stainless steel Coil