Noramlly there is a diaphragm valve that senses that the hot water is in demand , these diaphragms often split ( I have changed my one about 3 times, differnt boiler manufacturer though. ) , if you have a manual for the boiler it shoudl indicate that that is normally the problem. You should not need to buy the whole valve just the diaphragm from a plumbing supplies centre , not a DIY store.
Don't knwo why the taps would be hot without hot water ?
Of course this is only a suggestion there may be an electronics
fault whihc would do the same thing.
Philip
January 2007
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