On 23 Nov, 14:48, RobertL wrote:
My boiler starting doing somethng vaguely like that. *it woul *make a
chugging sound at about 5 Hz, and evenually the flame went out and it
had to restart.
it turned out to be that the flue had come apart in the loft!

On 23 Nov, 16:03, Peter Scott wrote:
Usually a problem with air flow up the flue. Either too much or too
little.

I'm pretty sure it's not that kind of problem, because the oscillation
frequency is much higher than I would expect from such a cause. The
boiler has a conventional through-the-wall concentric flue. Thanks
for the suggestions, anyway.

Richard.
http://www.rtrussell.co.uk/
To reply by email change 'news' to my forename.