Leaking expansion vessel schrader valve

[Barrie]

The schrader valve on my expansion vessel is slowly leaking air. I have put a valve cap on which has stopopoed it but should I pressurise it and is so to what pressure. The system is running at 1 bar. I am in the UK. I am hoping I can just pump it up a bit with a car pump in situ. Any help would be great.

[Mike90250]

Bike shops and auto parts houses should have new cores and a small tool to remove & replace them. As to what the proper pressure should be, I have no idea.

[Barrie]

Thanks

Yes, its easy to replace the valve, but I'km not sure if I can remove it while the system is under pressure and what pressure I need to put back into the cylinder.

[Mike90250]

Yes you can change it while water is in the system, there is a rubber balloon attached inside, and the air pressure inflates it, to balance against the water pressure. Spec for pressure should be on the tank label. My little 2 gallon tank has a 40psi pre-charge sticker. (thats no water pressure, pump it to 40psi)

YOURS WILL BE DIFFERENT. READ the label.

[inetdog]

Yes, its easy to replace the valve, but I'km not sure if I can remove it while the system is under pressure and what pressure I need to put back into the cylinder.

To remove the valve core, you will first need to use the valve to bleed off the air pressure. If no water comes out when the last of the air is gone, your tank is either at a high point or has a rubber bladder inside to separate the air charge from the water.
If water comes out under pressure after the last of the air, you will have to partially drain the system or risk having problems getting the new core back in against the water flow.