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

Hardware
1

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?

2

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?

3

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

4

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.