My Central heating and hot water just switches off. I turn the CH/DHW switch off then on a few times and it springs back into life. This lasts for about an hour then I have to de the whole thing again. Have been through the diagnostic guide ad it points to the "Change control board" option. I can hear that when I turn it on and it does not work that the fan does not start so I was going to change the fan until the diagnostic guide pointed to the control board. Anyone had this problem before ?

