Hello, I have got a torbeck cistern and every time that the pressure increases it starts to hiss at the valve and slowly releases water into the pan. This is the second time in as many years that I have had it replaced but no matter what, it continues to overflow. Has anyone got any ideas how to cure it cos the bathroom is close to our bedroom and her indoors, who is a light sleeper, can hear it during the night just when the pressure seems to be at its greatest. Please dont suggest ear plugs, cos it doesnt go down very well with her who must be obeyed!