... CCC,CE,ISO 3.Deliver time:Within 3days 4.Manufacturer evacuated glass tube DescriptionVacuum tube58-1800mm co-axial structure high borosilicate 3 ... in the top of the water tank ,and the cold water sink to bottom,then heat by solar collector.so the whole ... its valve,the tap water flow in the tank ,if the water is full,it will close the valve automatically evacuated glass tube for solar water heater