I can’t give you a hint to your problem, because I don’t have any Z-TRM3 thermostats in use myself, but it would be useful if you could tell which error it’s exactly.
If your Homey or the Z-Wave unit is indeed broken, then it doesn’t matter if e.g. Zigbee devices could be paired.
My recommendation is that you describe your problem in this thread. In this thread there are Heatit Controls staff active and they can probably help you.
