WTH thermostaat error code

[dchronakis]

I have underfloor heating throughout the house with WTH D9373 thermostats. One of these give me an error A2.1.

I tried to find in their website what that means but did not find anything.

Is anyone aware what that could mean?

Thanks

[DomP]

Did you find the issue? Does it work other than the error code or not at all?
I know someone who knows these things, what area you living?