Hi, Pleas can you assist? Water has been dripping out of the overflow pipe from the F&E tank in the loft for a couple of weeks and is steadily worsening. We have a very old oil boiler and central heating system and have not lived here long. There is a gravity fed tank for cold water to upstairs and the F&E tank for central heating. The issue is not the ball valve as this has been replaced on both tanks. Have been advised that it might be sludge build up, is this correct? If not what else May it be please? We had not been running the heating when the issue started, only the hot water during this time. The drip is pretty much constant, not just when boiler is on. I have noticed it stops dripping for a few minutes when the boiler fires up but then carries on. Any help appreciated, thank you.