Central heating loud clanking when heating up

[KennyPowers]

Hi all,

Got a central heating heating system that is around 30 years old now, with a Potterton Prima F boiler and 8 rads.

This winter, it's started making a really loud metallic clanking noise when warming up from cold. It does eventually settle down, but there are around 15 minutes or more of loud noise that wakes us up at night, and probably the neighbours too.

I did add a bottle of sentinel x200 into the header tank 4 weeks ago, then drained some water out a rad to try and draw it into the system.

If anything, this has made it a bit louder if anything.

Not sure what to do next, perhaps another dose of x200, but straight into a rad this time? I think the noise is coming from the boiler, and the pipes at the top. Maybe a scaled up heat exchanger.

Any ideas what I could try next?

Cheers.

 

[cross thread]

Sounds like “ kettling” it’s when the heat exchanger starts to scale up ,x200 may help eventually

 

[KennyPowers]

Highly likely it is, we live in a very hard water area as well.

So you think wait a bit longer, and see what happens?