Baxi duo-tec boiler clunking

[peter.cameron78]

Hi,

I find most answers I need in these, forums, but can't quite work out the answer to my current issue. Hopefully you can help.

I have a baxi duo-tec combi boiler. Circa 12 years old, but still in fine form. It's started making clunking noises on an irregular/daily cycle.

I've had it serviced (full strip down) and the noise persists, so don't think it's a heat exchanger or kettling issue. I'm now expecting it's either a faulty pump or air in the system.

The sound is similar to pinball machine while the ball is getting recycled.

Any ideas?

I have a video capturing the audio but it's not a supported media type so can't share here.


Thanks in advance.

 

[cross thread]

Is it happening on hot water or heating mode ?

 

[peter.cameron78]

Heating mode only.

It also seems not to happen if I drop the thermostat down below 50c (lower temperature) ... But haven't proven this over a longer time yet.