Found a relay (fan relay) on the high voltage circuit board that ticked when switching off but the contact still remained stuck. Tapping with a screwdriver handle released the sticky contactors.
Replaced the fan relay on the PCB and boiler is now working properly again.
What's worse is that I replaced this relay 2.5 years ago and completely forgot that I did it.
Thanks again for all your help, hope this post might help someone else in the future.
Replaced the fan relay on the PCB and boiler is now working properly again.
What's worse is that I replaced this relay 2.5 years ago and completely forgot that I did it.
Thanks again for all your help, hope this post might help someone else in the future.