We have a problem with a wall-mounted Ideal Classic combi-boiler installed in November 2004. About two months ago it started to make an intermittent very loud buzzing which lasts anything from a few seconds to a couple of minutes. Sometimes the boiler can go for hours without doing this, and at other times the buzzing is repeated two or three times an hour. It's very sporadic and irregular but the noise is loud enough to be heard from outside the house.
I wonder if anyone can explain this. Surely it must have happened elsewhere.

Steve, January 2008

Just to update the forum on this, we have now had the gas valve replaced, and all appears well, though the engineer did indicate that the "next thing to go" may well be the PCB(!), but we are hoping that will not be for a very long time yet, as we have forked out a lot of money this year on a replacement fan and now a gas valve... pretty unimpressive for a boiler that's only 3 years old.

Steve, February 2008

I've actually made a recording of the buzzing which, as I mentioned, is totally unpredictable and varies in length from 2 seconds to over a minute, but I can't see how to post any attached file on this site.
It's really quite loud, louder than an electric clock alarm for example, and is really quite irritating. My wife and I suspect it might be the solenoid or an electrical relay(?) but my knowledge on these matters is very limited.

Steve, January 2008

My central heating system does the exact same thing. My buzzing happens just before the fan kicks in so I am sure it has something to do with the ignition system but I haven't quite figured it out. I know we are talking about two different types of heaters, but they both use gas, so maybe yours is also an ignition problem that happens as the boiler fires up?

Chuck, January 2008