I've got an old condensing Minimiser boiler (which I plan to replace soon, but for the time being - that's what I'm stuck with), which works fine - water gets hot, central heating works. The problem is that something in the loop makes a lot of rumbling noise. Noise pattern is unusual - when boiler starts everything is perfectly nice and quiet and stays like that for 4-5 minutes. Then, for another 4-5 minutes, I can hear loud rumbling noise. Then it quiets down and everything becomes silent until the boiler powers down. The problem is that I cannot locate the source of rumbling sound - it's neither my boiler nor hot water tank and its surroundings, including all the pumps. Acoustics can be tricky, but it surely is something hidden, I guess pipework.
My question - what can cause such noise pattern? For limescale I'd expect rumbling all the time or at all. For air in the system - it should move and pattern should change. I'm out of ideas. Can anyone explain that? It's also worth mentioning that it all started a few months ago. There was no noise at all before and noise pattern is identical every single time since then.
My question - what can cause such noise pattern? For limescale I'd expect rumbling all the time or at all. For air in the system - it should move and pattern should change. I'm out of ideas. Can anyone explain that? It's also worth mentioning that it all started a few months ago. There was no noise at all before and noise pattern is identical every single time since then.
