Many thanks Nickso.
To check if the pipe is blocked, are you referring to the flexible pipe from the air vent?
The service manual doesn't appear to mention repressurising the expansion vessel. Do you know the location of the pressuring valve?
Thanks once again.
Vokera Linea 28 Combi.
I recently emptied the central heating so as to renew a couple of radiators.
When I refilled the system, the automatic air release valve (item 25 on page 1 of the Linea 24 & 28 Installation and Servicing Instructions manual) badly leaked water out of the top...