My next door neighbour has a Worcester Greenstar 30CDi Conventional boiler, which is between 2 and 3 years old.
About 12 months ago, he changed a number of radiators and thats when his problems started, with code E9. I have now resolved that problem, where the pump was pumping in the wrong direction.

However, he is now getting the fault code EA - Flame not Detected.
I have checked the condesing pipe is not blocked and drained the condensing syphon as I have read both of these can cause the code. Now the boiler will run quite happily (it did this for several days), with the cover off, but as soon as the cover is put back on the boiler on its first heating cycle it will give code EA when the water temperature is normally between 50 and 65degC. My current thoughts are that there could be a problem with the igniter lead or electrodes and this is breaking down with the case on, could it be a problem with the ionisation sensing electrode or lead?
Alternatively it could be a gas pressure fault, but I have tried lighting all of their gas hob rings and this did not cause a problem or could it be a temperature sensitive problem?
An obvious suggestion would be to run it with the cover off, but that is not acceptable due the flue fan noise and also small grand children regularly visiting.
Anybody got any suggestions, before I start costing my neighbour money by replacing faulty or non-faulty parts?