if your radiators heat when running a hot tap & your hot water performance is down a bit the 3 way valve / changeover valve is passing. not a big job , but tricky , contact vokera & ask for your local listed agent , this gives you a company linked to & approved by vokera and guarantees the work done ie if vokera recommend someone & they dont fix it then you can complain to vokera !!
phil
November 2007