... pressurized 3. 15 Years Warranty for vacuum tube solar water heater featuresa. Module design, arbitrary combination, harmonize with the ... copper and conducted by heat transfer medium liquid2) Temperature preservation is equipped with standard electric water heater setting,automatic ... ) With heat pipe: anti-freezing > -35 degrees centigrade9) Water capacity: 150L, 200L, 250L, 300L, 500L 10) Pressure: ...