Webasto Fault Code

[Cornishkiwi]

Hi all

I was wondering if anyone knew what F84 fault code meant on a webasto Thermo Top 90?

I presumed it was voltage originally, as would show the code sometimes when the engine was off, however when ran the engine it worked fine. Been several months now and it's now stopping and showing the fault code regardless whether engine is off or on.

I can find upto fault code 19 online but nothing saying exactly what F84 means.

Any help would be much appreciated.

Thank you

Keiron