I have a 5 year old microgenus 27 Ariston water boiler. Recently the flames have been going on and off in both hot water and central heating modes whilst the fan has continued to run. So from the tap I get hot then cold then hot etc. With the heating on the radiators take ages to warm up because the flames are out more than they are on.
5 visits from Ariston nominated engineers have resulted in renewals of the thermistors, the electrical control panel, the air pressure switch, the main flow control valve and the cleaning out of the heat exchanger,with no success. In fact after the APS was changed the hot water was on for even less time than originally so it was worse still. The APS was part 571651 which the Ariston tech department tell me is the correct part,but I have my doubts.
I am now being quoted 2 grand for a new boiler.
Does anybody have any ideas?
Thank you.

Baby Gear - Combi - Centre DX - Mango