... 4.Best price with high quanlity DIY solar hot water Non-pressured solar water heaterWater Tank:1,SUS304-2B Inner tank.2 ... always circilating continuously3,The electromagnetism or ball valve can perform the water supply automatically,the water in the tank is not sufficient, ... the electromagnetism valve will open its valve,the tap water flow in the water tank,if the water is full,it will ...