John Rumm wrote:

Patb wrote:

After replacing the ball valve, thinking that was leaking and causing
the overflow to go, I have just realised that warm water is coming up
from the immersion in the bedroom up into the loft tank.
Grateful for advice on what I should do to stop this,


Could do with a little more information to answer this...

How is the hot cylinder heated - just the immersion, or is it also
heated by the central heating?

If so, what type of central heating system; vented (i.e. with a little
header tank in the loft) or sealed (no tank, but a pressure gauge and
filling loop)?

How is the warm water getting into the cold tank? Via the feed pipe that
goes from the cold tank to the base of the cylinder, or via the vent
pipe that discharges over it?


The usual problem is a leak between the primary and secondary hot water
circuits. A new cylinder is likely to be needed.

Bob