i have a vailant vuw282 turbo max the heating system works fine, but the running water isnt getting up to temperature there is a slight leak from the diveter valve by the micro switch and the divertor operates the microswitch on and off causing the boiler to cut in and out during hot water demand. but when i tested the system by physically keeping the switch closed so the boiler wouldnt cut 'in and out' the water temperature was still not getting up to temperature. any ideas ? my only thought was the heat exchanger can this be cleaned easily.

martin, November 2007

It does sound like the heat exchanger is possibly scaled. Not easily cleaned but is possible.
Id suggest getting hold of a diverter valve service kit too. This replaces all the diverter internals

Mr A, November 2007