... & pressurized 3.10 years warranty Water heater systemWorking principle:when the diffeference of collector temperature and tank temperature ... new trivalent element heat tube, borrosilicate glass 3.37) Solar working station8) With heat pipe: anti-freezing > -35 degrees ... Pipe pure red copper TU1+water,transfer power>=150W,Working pressure,4Mpa,welding pressure 4MpaDust Ring GasketSilicon Rubber Vacuum ...