Honeywell Z-Wave Thermostat TH8320ZW1000 keeps reseting AC to 10 degrees

When I set my thermostat by any means (even the device directly), the first time I set it it works. The second time I set it (to a lower value), it resets to 10 degrees.

The OpenZWave log looks like (when it fails):

Value::Set - COMMAND_CLASS_THERMOSTAT_SETPOINT - Cooling - 1 - 2 - 1 - 23.5
Value Updated: old value=29, new value=10.0, type=decimal

After that it doesn’t matter what I do, I can no longer set the temperature. My only guess is this is maybe related to the Heating 1 vs Cooling 1 temps or something?

Further investigation yields it’s the decimal. Setting to 23.5 causes it to drop to 10, but any whole number like 23 will work fine.

Anyone seen this before?

Looks like a bug in OZW that can be solved with a cfg override…

If anyone else has this thermostat and encounters this, I did submit a pull request to fix this in Open Z-Wave which was accepted.

This should solve the issue for this specific thermostat moving forward. However I have now moved back to the ‘legacy’ z-wave support in HA due to the high number of bugs I encountered with Open Z-Wave.