"Andy Wade" wrote in message
...
John wrote:

If you have replaced the float valve AND there is no sign of it dripping
when up to level then you may have a leak in the coil inside the
cylinder
which is allowing water from the heating system to make its way through
into
the hot water (tap) side. This may be evident from a dribble from the
heating header tanks ball float valve without attendant rising level in
that

But only if the CH F&E cistern is at a higher level then the DHW
cistern, surely. If both cisterns are standing on the same platform
that the flow would go the other way, would it not?


Thats why I said "may" have a leak