Roaring noise from behind my chimney

[wolfie882]

Hi

A newbie’s first post….!

Don’t know if anyone out there can shed any light on a strange “problem” I have.

My central heating system is pretty straightforward - I have a Baxi Bermuda back boiler behind a Baxi fire. Over the last few months I have heard an unusual “roaring” noise coming from the chimney breast area above the fire. Put my ear to the chimney breast at head height and it sounds a bit like a kettle is boiling inside the chimney. Lower down by the fire the sound still there but is less apparent. The fire is off during this time. The system timer clock is off.

It only ever happens early in the morning (6 - 8 am) and each time the noise appears approx once an hour and only lasts about 10 minutes before fading away.

I have had the Baxi serviced, and had a drop test done for leaks, and the bottom of the flue checked and everything is in order. The engineer who serviced the boiler says that from what we describe it sounds like the boiler is firing. Don’t think that is the case because there is definitely no burner flames visible underneath the boiler, and the roaring sound does not appear to be emanating from behind the fire and it is not quite the same sound as when we switch the boiler on.

This morning I experimented and turned the gas supply off at the mains and……………….no roaring sound!

It’s a real mystery!

[rosebery]

Been doing it a long time or just since the service? If the latter get 'em back to do a better job of sorting it out.

Alternatively just turn up the volume on the TV (joke OK?)

Cheers