decker wrote:
I have a strange issue with my central heating. Moved into a new house
3 years ago and heating worked fine for a year, then last winter we
had an issue where it wouldn't turn off.


I had something similar with a different type of heater.
I was told by the supplier (but never got around to it so dunno if it
would have worked) to surpress(?) the mains 'lead' near where it
connects within the heater by wrapping it around a ferrite ring.