Ideal Logic FU Fault - Tado Issue?!

Hi all,

Recently we have had some issues with our Ideal Logic Boiler whistling / whirring as it fires up. It doesn't happen every time, but it's noticeable when it does, and it's started happening in the last few months.

Initially we thought this was a boiler issue, despite the boiler only being two years old. We arranged for the manufacturer to come and look at it, but they confirmed the boiler is absolutely fine (to the best of their knowledge).

They did however say that it has lots of FU faults, which I believe is to do with a temperature differential of more than 50°.

This then led us into looking at the Tado setup. He asked me to switch off all radiator valves through the Tado app, which I did, however the boiler kept running for around 15-20 minutes afterwards. Historically when I've tested the link between Tado and the boiler it's always been very responsive, with commands taking no more than a couple of minutes to work.

When we tested all the radiators to see if they were hot, the kitchen radiator was still on and piping hot to touch, even though the valve should have turned it off about 20 minutes prior. What's more, is that particular radiator is independent and isn't configured to be able to switch the boiler on itself. It will simply turn on if one of the "master radiators" is calling for heat. Possibly coincidentally, on reflection the whistling we've been hearing on the boiler has been since we changed the valve on the kitchen radiator to make it Tado-compatible.

I can't find anything remotely related to this online so I'm still none the wiser as to whether this is a boiler issue or Tado issue, but I wanted to check on here.