water pressure sensor faulty,if you look at the manual ,it is a disc with 2 wires connected sometimes just swiching the wires resets the boiler to working order,turn the boiler of at the mains (electric)and the swich is located on the right hand side,swich wires or replace the swich,always use a corgi registered installer,find one on gorgi web site
stew, December 2008
