Rought cost to replace an expansion vessel

[MJN]

I have a contract of flats with Un-vented HW cylinders and whe I am there , I do 10 a day servicing them and this is part of the service, this is the service procedure that the manu insists on, who am I to argue ?

As I said; experienced!

 

[Harry Bloomfield]

could just be condensation within the vessel, the correct way to test is, remove system pressure with a drain point left open, close the drain point when nothing more comes out, remove shraeder valve insert , re-pressurise system until all water and air stops ,install a new schraeder valve insert then open drain point and re-pressurise vessel, you will know instantly if the diaphragm is punctured, pressing in the insert tells you nothing

If I understand this correctly - surely the flow of water out of the valve would be minimal and quite quickly stop, if it were condensation. If the water continues to escape then it must be punctured?

 

[ianmcd]

If I understand this correctly - surely the flow of water out of the valve would be minimal and quite quickly stop, if it were condensation. If the water continues to escape then it must be punctured?

not all expansion vessels are the same, you have to follow the instructions from the manufacturer of each expansion vessel, in my opinion probably the most common replacement of any component in any heating system that didnt need replacing, because so called engineers press a schraeder valve and get damp, and think they know what they are doing