alpha 280e combi

[nige1]

Have changed prv valve but the boiler still loses pressure overnight if i overfill past green bar pressure goes up to 2.5 and prv valve opens have checked for leaks.
any ideas
thanks

 

[Puddle]

re prime expansion vessel

 

[nige1]

Hi no expansion tank fitted on the boiler

 

[payney1974]

wheres the expansion vessel then? are you sure its not behind the boiler?

 

[nige1]

hi how do you prime it
thanks