I have a ferroili combi 76ff which was fitted about 17 years ago. It has been a relatively reliable boiler, but just recently started an intermittant fault of pilot going out and not relighting. Now, the fan is working, but the pilot is not attempting to light, no spark or anything. I thought in might be the spark igniter at fault, so I have tried lighting with a lighter, but still nothing. So I assume no gas, but with no spark either could it be the PC board or is there a comon fault on this model?