Hi all, I have just had the same problem. My condensate pipe backed up with water because of frost outside this initially shut down my boiler as a safety feature. once I released the water by removing the pipe. I tried to re-start my boiler, however the flame would light for around 10 seconds then cut out all together. After reading i needed to spend a few hundred quid on an engineer and pcb board on the web I looked into it further. A white wire goes from the pcb board to the top of the condensate tank inside the boiler, if this wire is still damp on the terminal on the top of the tank from the condensate back up then the boiler still thinks it has a problem and cuts out. I got a hairdryer on it for a few minutes dried it out tried my boiler and it worked. Its worth a try anyway, hope it helps thanks, Dave..
Dave Leyland, December 2010