how do i stop a cistern from filling up even though the tank is full, it is as if the full tank indicator mechanism is not working, or disconnected. the brand is a caroma trident dual flush cistern

steven, February 2011

I have a Grohe EAU2 Cistern (2-years old) which also occasionally runs non-stop into the Bowl. Most of the time it works OK, but then it will run all the time. To stop it I press the flush button a few times. I have examined the Discharge valve which looks good. I think PP's comment on Brain Power doesn't answer this problem.
I would very much appreciate any advice on my next step.

Ian, February 2011