I'm getting a low droning sound coming from within the boiler (Keston condensing). It sounds like a small, low flying aircraft!This happens even when the boiler is "off" with the pump "on". We've just had a new bathroom fitted, so the system was drained down but it was all well
- for about 4 weeks, just using the HW side of things. It is a sealed system, under pressure. Then I bled all the radiators & checked they all worked. Ironically this probably introduced Fernox MB-1 which was introduced via a new towel rail radiator. Once the cycling water gets hot enough, it resonates from within the boiler . . I've vented the system, there doesn't appear to be any air in it . . . any ideas? It is an old system but as I've mentioned, it's worked extremely well until I checked out the CH part . .?
Cheers
Steve