Hello neil, i had the same probs with my 24i,had a guy out of the yellow pages and he said 100% its the pcb the main board needs replacing £180 quid, so when he went i looked up on the net how to fix a combi 24i, common faults are the main board gas valve and fan, all i done was tap the gas valve with a peice of wood and pressed the red reset button that is on the very top of the boiler and it fired up, also make sure your water pressure has not dropped below 1 and a half as this will stop the boiler from starting too, hope this helps dude, keith. p.s dont always believe everything that the so called experts say it is?
keith, February 2009
