Problem with Ideal combination boiler, even after power flush!

[MS56]

Hi, I have a problem with my Ideal Combination boiler, a mini C28. Over two weeks ago, the heating stopped working, the hot water was ok. When we switched on the heating, the gas would ignite for a few seconds only but then cut out, leaving a whirring noise in the boiler. After a few minutes the gas would ignite again, and then cut out.

An Ideal engineer came out and advised that the heat exchanger and pump needed changing because they were clogged with grime, but that a power flush was needed first to clean out the system. We had the power flush completed with the result that the hot water stopped! So no heating now, or hot water.

Today, the engineers came out to fit the heat exchanger and pump only to have the exact same problem - hot water (restored), but still no heating and the same thing happening with the gas cutting out after just a few seconds. The engineers claim the boiler is fine and that the system needs flushing again. Is this possible? We've had little faith in this boiler from day one and the plumber who carried out the flush says that the system was relatively clean and that he would have detected any major problems - which he didn't. Now, we just don't know what to do. Help! We are losing our minds.

Any advice?

 

[Billy Bob Bob]

ch thermistor, external controls,and diverter motor need verifying

 

[MS56]

Thanks for that