Over the last couple of months I have been getting a very loud noise from the plumbing when the downstairs toilet has been used. It is when the cistern is being refilled and it happens just before it is full when the flow into the system is slowing down and just about to stop. The only way to stop the noise is to turn a hot and cold water tap on.
I can't think why this started. The system has been the same for years without any problem. We did have British Gas to service our combination boiler just before the noise started. Could this have anything to do with it or is it just coincidence?
