Advice needed - expansion vessel charge

[Davedon]

Hi there,
was just looking for a bit of advice about my expansion vessel. My have a Suprima condensing boiler with expansion vessel - filling loop. The system loses 1 bar of pressure in 12-14 days. I have checked thoroughly for leaks and can't find anything, even a small one. I thought I would check my expansion vessel. I drained the system to 0 bar and checked the pressure at the Schrader valve and it reads 0. I have tried to pump this back up but almost instantly it returns to 0. My diagnosis is a faulty expansion vessel?! And hence the system loses pressure/water via the overflow pipe?
any suggestions?
many thanks
dave

 

[village idiot]

have a replacement vessel fitted on the return pipe or drain down a radiator and use as an expansion vessel.
better the first option though

 

[diamondgas]

Depending on the size of the expansion vessel it can take quite a bit of inflating before it reaches it's charge! If you're confident and it is possible to do so then remove the vessel from the pipework and pump it up. That way you'll know if the membrane inside is damaged 🙂