... 10 years warranty OEM service Solar Evacuated Tube Hot Water SystemBrief Introduction of Solar Evacuated Tube Hot Water High borosilicate glass ... 420/460/470mm2) Inner tank diameter: 310/360mm3) Vacuum tube counts: 15, 16, 18, 20, 22, 24, ... 26, 28, 304) Tube size: Φ47x 1, 500mm, φ58 x 1, 800mm5) ... aloy plate4) Insulation: 50/55mm polyurethane Solar Evacuated Tube Hot Water Systems