Open the pressure release valve and allow water out until boiler dial reads zero. Connect a footpump to the pressure vessel tyrevalve tytpe connector and pump it up to 1 bar reading on the footpump dial, (boiler dial should still read zero, if not keep the boiler pressure release valve open). Once footpump dial stays at 1 bar and boiler stays at zero you are almost done. Disconnect footpump, turn off release valve and repressurise to just over 1 bar using the tap either side of a flexible hose, or however you normally do it.
robbie repairs, December 2008