works ok for centralheating won't fire up for hot water, all fuses ok reset button in. thinking maybe something to do with diverter valve switch

bike man, May 2015

Most likely a worn diaphragm in the water valve.

To test the electrics side, there is a servo valve to the right of the electrical box, above the water valve. On the back of the valve there is an armature, push this down, if the boiler fires up, it confirms the diaphragm is worn and needs replacing.

Helper, May 2015