Baxi Bermuda 552

[Neil2]

We have an aging BB 552, it had a new heat exchanger fitted within the last 5 years after it dumped water all over the living room floor. Recently it has started to make noises which sound a bit like a kettle heating up. Is it possible for the exchanger to become blocked and cause hot spots and cause this noise? The system has always had Fernox in it and whenever I've had to drain and remove a radiator the water has always come out clear and clean.

 

[ChrisR]

Try a bottle of "boiler silencer" - usually helps a lot.
Could the pump be tired, causing a bit of overheating?

 

[gas4you]

Was the system powerflushed, or at least fully cleansed when the new HE was fitted?

It should have been, as fitting a new HE is the same as fitting a new boiler

 

[Neil2]

Thanks for those answers. The system was not powerflushed before fitting the HE, this job was done by a BGas engineer as we have a maintenance contract with them and I just left it to him to fit. The pump is relatively new as that has been replaced within the last 2 or 3 years.
It sounded to me like part of the HE was getting too hot and causing the water in that spot to start to boil so I increased the pump speed to maximum from midway and it did not improve things. I have since slowed pump to minimum and the noise has diminished, in fact almost disappeared and I would have thought it would make it worse. Is too much flow a problem??

 

[Neil2]

Further to my last posting. I will explain that though I'm not a plumber I am an electrician but have a very good idea of a lot of plumbing techniques.
I've since been reading the "FAQ's and Plumbing tips" section on boiler "kettling" and they recommend increasing the flow as one solution. When I did this it didn't help at all in fact it even made the noise worse, so, it seems back to front to me that by decreasing the flow it improved things.