In message , senga
writes
Ferroli Optima. Decided to check combi yesterday for water level. Pressure
was down below 2. Opened filler & let pressure rise to 2.5.

This morning turned on hot water but got none, checked pressure again & it
was down almost to zero, filled again & noticed overflow/safety release
valve was running outside & trickled away until pressure was almost zero
again.

Anyone who knows what my problem could be, everything was ok until I topped
up yesterday.

Err ... leaking safety release valve (as you said) ?

2,5 bar sounds a bit high, should prolly be nearer 1.5, look in the
manual

repressurise it to the correct pressure and open the valve - see if the
rush of water cures the problem (crud on the valve seat)

else replace the valve

--
geoff