I have a leaking overflow pipe, it used to connect to a hot water tank, but that was replaced a number of years ago by a combi boiler, so I dont know what is causing the leak?
may be obviouse but could it be your toilet ? if not then it might be the blow off pipe from ur boiler if too much pressure it lets water out at 3bar of pressure so id check that the valve/tap for topping up ur boiler is turned off if so the the pressure should drop to normal or the blow off valve may be passing if it was you wouldnt ave pressure in your boiler system ?
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