Franke Zurich mixer tap making noise All aspects of plumbing questions and answers, help, tips and information

[GlenQuagmire]

I have a Franke Zurich mixer tap in the kitchen. It's 7 years old. Several months ago I noticed a slight drip starting which was from the cold. More recently, I now can't turn the cold off completely as when it gets to a certain level, there's a whistling siren sound.,Turn it off any further and there's this horrendous foghorn noise. The house almost vibrates as it's so loud. The cold water is fed directly from the mains and the mains stopcock is below, in the cupboard under the sink. Any suggestions greatly appreciated.