Noise after boiler stops

[TaffSpur]

Hi all,

We have a Concord gas boiler and it runs fine and not particularly noisy in operation.

Lately after the first cycle of heating the water there is a rumbling/clattering noise about 30seconds to a minute after the boiler has shut back to pilot only.

The noise sounds as if it travels up the pipes and ends in the tank in the attic. It only seems to do this every few cycles of hot water heating and mostly only the first time it’s switched on. Any ideas?

Many thanks for your help, I’m a complete novice when it comes to this sort of thing,

 

[Ric2013]

Air pushed downhill by pump and settling out under gravity once the pump stops? Pump probably over-runs by 30 seconds to a minute after the boiler stops firing.

 

[TaffSpur]

Ric,

Many thanks for the reply.

What is the solution to this?

It seems to have happened when the heating control panel was changed and the guy who did it changed it from a two to one pump system and left the other pump in place but not wired in.

We had one pump for heating and one for water I think but now it’s just the one that does both.

Thank you so much for your help.

 

[Ric2013]

Could be air in the system from when it was drained and will eventually cease when the last of the air has worked itself out/to the top of radiators from where it can be bled off.

If you've had work done, this is also a question you should be asking of the person who did the work.

 

[TaffSpur]

Many thanks.

Will try to get it looked at, the work was done a year or so back now. Over the summer the noise stopped, even though it was on for heating the water but came back recently again.

Sounds like air to me by the noise, like I mentioned a bubbling/clattering type noise moving upwards. The boiler is getting on now but I don’t think it’s that as it happens a minute or so after the boiler has stopped.

Not sure if recommendations for work are allowed? I’m in Cardiff.

Any other thoughts please let me know and many thanks for your help.