My boiler make this noise every now and then! Any ideas?

[simondyntDBeK]

It's maybe 20 years old so possibly due for replacement but it works well otherwise. Every few days for half an hour or so after first coming on it does this!

Any help hugely appreciated.

https://www.icloud.com/photos/#0LWlzWv6aKijOqAcdjlHSVZUA

 

[ScottishGasMan]

Thats the sort of noise you would get if the heat exchanger is either scaled up a bit or is becoming pitted. Like you see there it happens at its hotest, like little microbubbles being boiled off inside the hex.

Its not likley to be causing any harm, if you had pipe temperature clamps you could measure the temperature at the flow and return as it was happeing to show if there is a restriction in circulation, or any excess temperature in the flow pipe.

 

[simondyntDBeK]

Thats the sort of noise you would get if the heat exchanger is either scaled up a bit or is becoming pitted. Like you see there it happens at its hotest, like little microbubbles being boiled off inside the hex.

Its not likley to be causing any harm, if you had pipe temperature clamps you could measure the temperature at the flow and return as it was happeing to show if there is a restriction in circulation, or any excess temperature in the flow pipe.

Thanks ScottishGasMan! Anything I can do about it? Or should I just leave it?

 

[ScottishGasMan]

Well, 1st thing would be to check the flow and return temperatures at the boiler with a pipe thermometer clamp of some description.

if the temperatures are ok (flow is not going above 80 and the difference between the flow and return is less than 12 or 13 degrees) then sometimes adding a bottle of noise reducer chemical to a radiator and letting it circulate can help. I always found using a gentle system cleaning chemical helped reduce these noises, but am hesitant to adivse you to add that, as if there is a point in the system either in the boiler or on the radiators that is very pitted, then the cleanser can remove dirt from the area opening up a weakness and causing a leak or pin hole from there, its not very often I've seen that, but it is a possibility once you start cleaning old systems to be aware of.

 

[ScottishGasMan]

If the temperatures are not ok, ie: flow temp is going over 80 or the difference in temperature of the flow and return are noticbly higher than the 12/13 degree sort of mark, then it would indicate poor circulation which could be sludge building up or perhaps a slow/weak pump.

Also check the header tank in the loft is full of water, can get noises if the ballcock sticks and it runs dry, more likley your notice an issue with poor heat to some radiators or the cylinder if this was the case though.

 

[simondyntDBeK]

Thanks. Great advice!