hi i have a ravenheat csi 85 AT boiler i get hot water but no central heating on the diverter valvethere is a switch i replaced it still did not work untill i pressed the button on it then heating came on untill i took my finger off button then it stopped again so i tested hot water it works on its own mode so pressed button again heating came on and i realised that it was still on water mode so synapsys water works in its mode but heating is always on in both modes untill you switch off i am stumped what could be the problem