The hot water on my Alpha Ocean 240e is only just tepid!!?

I have an Alpha Ocean 240e, It's keeping the radiators nice and warm but the DHW only gets hot if you run the tap at less than 10%. If you close of the heating flow, and run in hot water only mode, the heating flow pipe away from the boiler still gets very hot suggesting the DHW is getting into the heating loop somewhere. Has anyone any ideas where this is likely to be happening? Also in hot water only mode the top diaphragm (the smaller of the two on the diverter valve which I am guessing is for the heating loop)is making contact with the microswitch, is this supposed to happen? I seem to have lost the manual does anyone know where I could find a copy as it is no longer on the Alpha website?