... pressurized 3. 15 Years Warranty for vacuum tube solar water heater featuresa. Module design, arbitrary combination, harmonize with the building ... medium liquid2) Temperature preservation is equipped with standard electric water heater setting,automatic temperature control exchanger, and increased anode magnesium ... in winter)12) Heat preservation: 72h to 80h13) Electric heater: 1.5Kw to 3Kw