I have a combi boiler. The boiler allows you to have, just heating, just water or both. I can't get any hot water at all even when I put it on the 'just hot water' option, it just pumps water to the radiators (very hot!!). I have been advised that it is the 3 way valve that needs replacing and qutoed £200 to get it fixed!! I would like to attempt to do it myself, but don't know where to start. Can anyone help me or point me towards a good website with tips?? Any advise would be good!