In article , harryagain
wrote:

"therustyone" wrote in message
...
On Friday, February 13, 2015 at 8:22:04 PM UTC, charles wrote:
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


Are you in a hard water area? Could be accumulation of limescale
caused by failure or lack of additives or just many years use. Can be
fixed by Furnox descaler though it's a bit of a hassle. My boiler
tends to sound like my 3KW electric kettle when it's furred up.

Since there is no change of water in a heating system, there can be no
"furring up".

We've found the source of the noise. One of the zone valves was sticking
and closed with a "bang" rather than gently easing shut. This one had a
manual lever and I've opened/closed it a few times. Noise gone.

--
From KT24 in Surrey

Using a RISC OS computer running v5.18