Good Morning.

Gauge pressure reading relates to height of water in pipes above. What
you describe happening could be caused by failure of expansion tank or
of pressure-regulating fill-valve. Or both.

To diagnose and fix, I'd suggest you contact a competent plumber.

HTH,
John

Opuscm wrote:
I have a Vaillant combi bolier (about 10 years old) with the pressure
guage jumping to the max all the time. I have to use the pressure
release tap to release the excess water once every week or even every
two days!

I know the pressure represents the amount of water store inside the
boiler, so is it a problem with my top-up tap that slowly letting
excess water into the boiler or is it something else?

Thanks for any help or suggestions.


--
Opuscm