In article , harryagain
wrote:

"charles" wrote in message
...
In article , harryagain
wrote:

"charles" wrote in message
...
I was getting localised boiling (kettling) in my GlowWorm boiler when
the pump turned off. I've added ScrewFix Boiler Noise Reducer and
that problem seems to have gone. I now get an alarming clanking
instead which I'm sure wasn't there before.

Any ideas as to what is causing it and how to stop it?

Could be airlock but sludge is also a possibility causing local
overheating. Clanking is caused by steam bubbles forming and
collapsing. (Boiler is still hot, water circulation has stopped)
Causing the pump to run on after the boiler ceases firing is a "fix".
(You can try this to prove the cause)

This is not steam bubbles, I've got rid of those.


You might think you have.


There is pump overrun .

Boiler needs to be flushed out, ideally by removal and hose pipe
applied outside in the garden.

It was power flushed two years ago.


A con, "power flushing" has very little effect.

You are wrong there.

--
From KT24 in Surrey

Using a RISC OS computer running v5.18