I woke this morning to hear a persistent drip from the boiler cupboard. The central heating and hot water heating was both on. The drip was coming from the overflow marked by the red circle in the attached photo.
The dripping stopped when I drew some water from the hot water tap in the bathroom.
I assume this is something to do with a pressure release.
Research suggests that the expansion vessel might have failed or needs to be re pressurized?
I can see a shredder valve on the top if I 'reinflate' what should the pressure be?
If I replace should I be replacing one or both of the expansion vessels?
Will a new expansion vessel come ready to install or would that need pressurizing?