We have a Potterton Profile boiler fitted about 4-5 years ago by the
previous owners, it's started to go though a cycle, when starting up.
Switching the fan on and off for a couple of seconds until after 10-15 mins
it eventually fires up.
If anyone can point to the cause, if it's simple then I'll fix it, otherwise
I'll be better informed when speaking to an engineer.
TIA