There seem to have been a number of boiler threads lately. Mine is making a lot of noise recently but operating reasonably. Have a contract with Bloody British Gas who say that there is nothing they can do. They rebuilt it in the summer so I think and they have said it is safe, but the noise is annoying and getting louder over the last few weeks.
Apart from BGas I’ve had an independent look at it as well. He suggests scale and sludge in the system. He said a chemical flush would help but is probably £400 that might be better put towards a new boiler as the one we’ve got is probably 12 years old. Its a Baxi combi system with a mix of original rads and some that are about a year old.
So – new boiler, flush system, all new rads, ear defenders?

Ask a local chap to take a look at it before you do anything (if you’re not going to get the local chap to fix it though, do the decent thing and pay him for the call out).
I made the error of using BG for a little while. Mostly incompetent in servicing and diagnostics and keen as mustard to sell me a new boiler.

My boiler is about 12 years old now and went very noises last year. It was still working ok but was incredibly noisey.

The bearings in the fan were wearing out, the fan was replaced and the boilers been great since.

If you’ve an old boiler that is simple, I’d repair it and stick with it. The new boiler will probably break before the efficiency savings pay for it.

I get the impression that a chemical flush is largely a money making scheme as it gives them something to do which can be charged for but which rarely seems to do anything 🙁

See if you can work out exactly where the noise is coming from as that may help. Is it from the pipework? Try closing off various piping ‘circuits’ but shutting down the valves just to that area to see if you can isolate it (our office has one or two thermostats that get noisy at just a certain point. If you move them then they are quiet again). Does it only happen at a particular time of day or all the time (we had a problem in our house where the flue resonated at a particular fan speed at night – that was horrible to find). The more you can pin down where and when it happens the more chance you have of finding it.

If you can pin it down you may have some luck phoning around service agents for your particular machine and describing your exact problem

Good luck

Edit: as above a local chap is a good idea. I got a wonderful combination in once which was a father and son. The old guy had the experience of how things really worked but the son understood all the new computer stuff that was needed

My boiler (an old baxi combi) groans a bit if the pressure drops off, but still works fine. Worth a wee try.