hi all I have had a glow worm 30 cxi combi boiler installed, maintained, and trouble free for 7 years, recently we had a power cut and when the power came on again the boiler was showwing a F12 fault ,telling me to check the wiring, before I had chance to do anything we had another power cut, then when the power came on again the display window/screen was blank, nothing showing at all, I am not a boiler engineer, is there anything I can practialy do to find the fault before paying an engineer, my next door neighbour is an electrician although not a domestic boiler engineer, he has checked the wiring with a meter for current up to the circuit boards and display board and there is current to both any suggerstions please,cheers jd.