Can anyone shed any light on this? We've been living in a 1950s semi and the plumbing is pretty bad (lots of leaks, etc). About a week ago the feed and expansion tank in the attic overflowed as it is uncovered and some insulation fell in and pushed the ballcock down. As there was no overflow pipe fitted (!!!) the water started dripping through the ceiling. Anyway, sorted that out and have a plumber coming in to fit an overflow pipe and will get a cover for the tank. However, I've noticed that the F & E tank has no feed pipe attached, just the water inlet and ballcock and the curved pipe for the expansion. How is this possible? Where is the water feed coming from and expansion occuring? And so what's the point of having a water supply to this tank? Any advice appreciated!