I have just had a new central heating system installed, however when i switch the sink tap on, put shower on or flush toilet, occasionally it will switch the bath tap on. I spoke to a plumber and he said I must have left the tap on as taps don't just switch on, but it has now happened three times and I know the tap has not been left on. Please, can you give me some idea of what the problem could be and any solutions?
thanks
alison