... 2.Anti-freezen & pressurized 3.10 years warranty Solar water heater frame Material of Model:1.the heater pipe ... thainless 1.5mm,normal working pressure:6 bar5.workstation:circulation pump RS-15/6wilo,controller,expansion tank(italy)6.the insulating ... capacity: 150L,200L,250L,300L,400L,500L,600L,700L,800L............solar water collector1) Reliable, efficient, twin-glass evacuated tubes2) Red copper( ...