... CE,ISO9001 certificate 2.Offer OEM 3.15years warranty 4.20 days delivery solar hot water heating systemFeatures ... the heat to the water tank, and produces hot water 2) Easy to use, also convenient to install 3 ... tap water, and the outlet hole produces pressure hot water directly 5) Working principle of low ... in the vacuum tube directly, through the cold hot water convection, changes the solar energy into ...