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Tim+[_5_] Tim+[_5_] is offline
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Default New Cylinder needed for system boiler fitting?

jkn wrote:
On Tuesday, June 15, 2021 at 10:27:37 AM UTC+1, Roger Mills wrote:
On 13/06/2021 16:18, jkn wrote:


FWIW one reason for doing this *now* is that the back boiler has starting making
'kettling' noises when it starts up. We've fairly recently set the controller to not put
the radiators on, but I wouldn't have thought that that would have caused any such
issues? It is looking to me that the heat exchanger is really sooted up - I actually
fitted a new thermocouple, and cleaned the jet out, a month or so ago, and it seemed
fine then. I'd quite like to fix/understand that even if we do finally sort out a
new boiler...

J^n


Hi Roger

What colour is the boiler flame? If the HE is sooting up it suggests
that there's not enough oxygen, so the flame will be yellow instead of
blue. Make sure that the air supply to the burner isn't blocked and - if
possible - check the gas pressure at the burner when it's firing.


The main boiler flame seems pretty yellow (and I think the window for
examining the pilot light is sooted up) - which is where I came in, I recall
it being much bluer a month or two ago, when I fitted the thermocouple etc.


You know, this sounds really quite dangerous. If you dont have a carbon
monoxide alarm get one pronto!

If Im right in thinking this is an open vented boiler it could well spill
combustion gases back in to the house.

As Im sure youre aware a yellow flame means that the gas/air ratio is too
rich. Whilst occasionally gas regulators can go wrong and deliver too much
gas, its more likely due to poor air flow through the boiler.

This can occur on the inlet side if its choked with fluff (which is easy
to see and cure) but it can also occur due to a sooted up chimney. Once
you have a situation where soot is settling in the chimney it creates a
positive feedback loop creating more and more soot.

Until youve got this situation sorted be very careful about using the
boiler. It needs a service urgently and the chimney almost certainly needs
to be swept!

Tim
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