Add 20 - 25 litres of water to the kettle.Attach the column, but do not fill the column with Raschig rings.Insert the bung with thermometer.Connect the cold water supply to the inlet at the bottom of the condenser. Connect a discharge hose to the warm water outlet at the top of the condenser and lead the discharged water to a drain.Turn your heat-source to high and when steam (very hot! - beware!) comes out of the condenser, run cold water through the condenser.The condensate will be pure distilled water.Stop distillation whilst there is still at least 5 litres of water in the kettle.