I have recently noticed that the my overflow to my central heating header
is dripping. My first thought was that maybe the ball valve was over filling
on inspection the cause was found to be water dripping from the expansion
into the header tank.
I don't know why this has started to happen. It usually stops while the
water is actually on, i.e. the pumps running, but as soon as it stops if I
grab hold of
the expansion pipe I can feel it heat up as the hot water rises up it.
I have tried emptying the header tank down to its correct level but by the
it had filled itself up again.
Any ideas greatly appreciated.