... 3.5 years warrnty 4.CE,ISO9001:2000,SGS,CCC project solution feature : 1.Mainfold: Combine 50 or 60 pieces vacuum ... make one vacuum tube solar collector.2. According to special project hot water capacity , local weather condition, Final temperature require, We ... heater and circulation pump etc part.4. The whole solar project system are automatic operation. when in coldy or rain day ...