Combi Boiler Cutting out - Ariston A/23

Hi friends ..
I hope someone can help and advise me ...
This boiler was fitted by me ...then checked and commisioned correctly by a proffesional over perhaps 10 years ago ...
It has run absolutely trouble free for all those years ...but I suspect the recent cold spell had it working overtime ..
..and it looks like it has developed its first fault..
The Combi is a large Ariston A/23 MFFI ...and I can get it to start for short periods ...then it trips and the red warning light on the left front comes on and the boiler shuts down until it is reset..
It matters not as to mode ...ie ..it will trip when just using CH or indeed ..when using HW ..

I suspect its getting too hot and a thermostat trip is operating ...
This can activate within minutes...
Of course ..it couldn't have happened at a worse time ..than during a rather cold winter ..
I'm no expert on boilers ..but as a TV repair technician ..I do have a versatile skillset and a logical mind ..
I first suspected the CH pump not circulating the hot water away from the boiler ....but since it trips with no CH ...and just drawing hot water ..I discounted that ..
I don't believe this to be a gas related fault ...and thats one area I wouldn't tamper with anyway ...
So ...I'm now suspecting the heat exchanger ...or possibly a faulty thermostat ..
Any help you experts can give me would be most appreciated ..
Maybe this is a job I can tackle myself ...but if not ...I would at least like to have some idea before contacting a heating engineer.
many thanks for reading..
Keith

You obviously have your own ideas, perhaps you think the switch mode power supply has failed or the field sync has lost lock?

However, I think that its a gas related fault and the first thing to do would be to check the gas settings.

Tony

Assuming this is a eurocombi the furthest left led indicates ignition failure.

Most of the checks would involve gas but you could check the right hand board which monitors flame rectification.

Thanks for the quick replies ..
If it is ignition and therefore gas related ...then I would certainly get a heating engineer to look at it ..

Its odd that the ignition works ...the boiler starts fully ..
hot water is circulating around the rads for a good few minutes ....before it eventually cuts out ..and the red light above the button comes on.
Which is the only reason I thought it might not be a gas related problem..
..but I thank you for your input ..as you are after all the experts
rgds
Keith

..forgot to add ...
..there is a picture of a thermometer beside the button and red light ...
Which I assumed to indicate ...overheating ..
cheers

Wow, I sure hope we can find an answer for this one because it's becoming a real, serious hassle - and an expensive one, too. I have an Ariston 23 which is cutting out constantly. Okay, so I leave the heat on 1 when I leave the apartment and you can be sure when I come back after a couple of hours it has cut out and the red light is on.

If you turn the CH to 0 then hit reset and turn CH to 1, it comes on for a minute then stops and I get the red light treatment again.

So then I 'fool' it. I turn CH off, push reset, then turn on the hot water just to get the boiler to kick in. Then after a minute of hot water running, getting the temp up to 50, then I turn CH on and it seems to stick for a bit. It can stay on for up to three hours, but generally cuts out after an hour or two.

I had a heating guy come in and he changed some tap which did nothing, then returned and changed the printed circuit board (I wasn't there when he made his repairs otherwise I would have grilled him whether this was necessary). I'm now up to roughly £250 of repairs. The repair guy leaves and now the heater can't even be turned off. When you turn the start button off it stays on. So he returns, plays with something and now at least I can turn it off.

I called him today and he was pretty upset. He says they don't make the PCB for this anymore and he had to 'play with' another to adapt it to my heater, and that may be why it's not working. Being a novice with heaters, I don't know what to make of any of this. I'm a tradesman so I've got good common mechanical sense, but this is my first time dealing with heaters. (For info, I'm in France dealing with a French heating guy)

As with the comments above, what's the chance this might be a gas problem rather than anything to do with the circuit board? If it is a problem with the circuit board, is it still possible to get the right replacement piece? And should I get another heating specialist? This guy says he doesn't know what else to do. Any help would be very much appreciated.