Hi,
I have a chaffoteaux 30FF boiler in which I had the PCB repaired (by Geoff I believe.) That was several years ago and everything has been fine since. A few months ago after a cleanout I couldn't get the pilot to stay lit so I put in a new thermocouple. The boiler has a high-heat cutout and this seems to make the thermocouple very sensitive. I actually just had to adjust the tip a little to get it to work.
This weekend the pilot light went out, but the high-speed fan still kept coming on, as if the boiler was firing up, even though the pilot was out. This doesn't sound right to me, does it to anyone else? I did manage to get the pilot relit and it's been fine since. The pilot does look a bit weedy - more of a round flame than a pointy one.