... :CCC,CE,ISO9001:2000 4:Produce as customer's requirment Low pressurized solar water heaterSpecifications1.Solar Keymark,SGS,CE,CCC,ISO9001 ... be installed on the roof to get enough water flow pressure, because the compact system is non-pressurized, water flow depending ... inside and complete a circulation on it own without given pressure, that is how the name comes fromMaterial date:1) Thickness ...