Non-pressure solar water heaters(ss) 1.CE,ISO9001,CCC, ... -10 per hole 3. 15Years Warranty for vacuum tu Non-pressure solar water heaters(ss)1.CE,ISO9001,CCC, ... Dual-level ramp.Technological advance: the use of more safe, non-troubled waters, anti-burst, antifreeze, E-nrichment process.Collector ... thickeningWorking pressure: no pressure to runWater method: water law. Non-pressure solar water heaters(ss)