Hi all, wondering if someone could shed some light! A friend of mine (RGI) asked me to have a look at this boiler, as his staff had decided to throw PCBs at it! The fault occured after a power cut. The boiler turns on, the pumps start, but no ignition sequence. It's had one Aqua(?) pcb, and two ignition pcbs, symptons still remain. After checking a few things, I decided to meter the Flame Sensor, using a Fluke set to Ohms, between the ignition PCB and Earth. The boiler then went through its ignition sequence and fired up correctly. I then found that by directly earthing the Flame Sensor, I could also get the boiler to fire up. Ideal Technical suggested an earthing issue, but I Meggered it all, no fault found. We also extracted the burners and checked/Meggered the ignitor and Flame Sensor, all OK. Any suggestions???