solar water heater, pressurized, easy installation, economical, save money, high quality,popular with people all over the world solar water ... -S serials is Thermosyphon solar water heater, That is a kind of solar water heating system that solar collector and storage are ... 5°C per day7) Optional accessories: assistant tank, electric heater, reflector ,automatic inlet water valve, Magnesium anode, ect. ...