Boiler not firing up

[PEG]

Just on the subject of flame rectification...i got to talking about this process,with a heating engineer pal,and he said the boiler manufacturer he was accredited for,just had a simple set of tests,to identify a rectification issue - then they replace the assembly.
He wanted to know the method of it's operation,and if each step could be tested.
I did this with him,and on the strength of it,he has purchased an AVO 410 Megger multimeter,which is what i used,in the demo

 

[DIYfan]

Just bumping this one again.

The boiler broke down again, had my regular repair guy out, it was the thermostat that had gone, he came yesterday and fitted a new one.

All working fine though now it keeps firing up a lot more like every couple of minutes. I spoke to the repair guy who basically said it was nothing to do with the new thermostat, see how it goes, it's a 20 year old boiler etc, wasn't really bothered as it's working.

Any ideas why it would be doing this? thanks