"Grumpy owd man" wrote in message
news:3c270227b3833fa7756c53109fec9676.115311@mygat e.mailgate.org...

0.5 and 1 bar when cold. If the valve drips even when cold replace it.
If
it drips when hot then check the pressure vessel pressure or if the
diaphragm is holed replace it.


Ah!, I have not really explained it very well.
the water is coming from a pipe which runs to the outside of the
property if this make any difference. The drip is not internal

Exactly. It is the pressure relief valve which is piped to outside. You will
know if the diaphragm is holed as water comes out of the shrader valve.