you have a great boiler apart from a dodgy pcb problem, so you have changed the pcb for the up graded version, which includes the rewire of the whole boiler electric's. and it worked ok for a few weeks ,so you must have done a good job. Ok. the new board has its own diagnosic light , the new board kit came with a manual, read this and see if the flashing light tells you what is wrong. If the indication light said that there is no demand then its the external switches not giving you a switched live back. Also did you change all the wires that were sent with the PCB kit in perticluar the spark electrode wire.
andy the gas man, July 2008
