In ,
Dave scribed:


No drips.
The expansion vessel is built-in to the boiler (30SXi).


What do you mean by 'built-in'? If you mean it is an integral component of
the boiler unit hung on the wall, then yes, so is mine, but it can still
fail/leak. Can you not take a pressure reading of that expansion vessel
alone?

As suggested in the FAQ, (and I have had to resort to this while I await the
arrival on my new expansion vessel), try creating a temporary expansion
'vessel' from one of the least used rads on the circuit. You'll have to
drain it of liquid first, and then shut off just one of the valves allowing
one connection to operate as the pressure 'overflow' into the rad. When I
did that, my pressure loss which was previously at around half a bar per
day, almost stopped completely and now drops less than that in a week. ;-)

hth
Nigel