Boiler heating running continuously ariston Clas he30

[Thomo100]

Hi
I've woke this morning thinking feeling like I had a fever but found all the radiators roasting.
The central heating is actually in the off position and we just boost it when required at this time of year. I suspected my wife had hit advance instead of boost last night but no it's in the "off" position. It's an Ariston Clas he30 system boiler, there was an orange led lit in middle of panel below display ( icon with a tap but the manual doesn't say what this led is?) i had to turn off boiler switch to get it to stop. The boiler was turned up quite high80% of the temp setting and everything has worked fine for last 6 years.

Guessing its most likely pcb issue, as no call for heat causing boiler to fire up has to be something to do with the thing that controls it?
Any other tests worth doing to confirm
Thanks
Pete

 

[AGAS]

i hate this boiler don't have much doing with them , there is more to check before thinking about changing the pcb

 

[DP]

Agree with Agas, regards quality of product and suspecting PCB being the culprit causing boiler to malfunction. A few months ago ripped out this model as it had too much wrong with it.

You need to call a heating engineer who knows how this boiler functions, so will be able to access why it is misbehaving