I got a malfunction on my GoControl thermostat this afternoon. With the thermostat mode set to cool and the temperature between the heating setpoint and the cooling setpoint, the operating state changed to heating. I changed the mode to off and the operating state stayed heating. The mode change was reflected on the device display, so the device has battery power and is communicating via Zwave. This is the device page after I changed the mode to off:
I changed that zone to use a different thermostat, which stopped the system from commanding heat. After a few hours, it seems to be working correctly again, although I am hesitant to trust it.
Is this something that could happen due to a ZWave message getting mangled? Any other idea of potential causes?
I have had this exact same thing happen to me 2 times with a generic Z-Wave (non-plus) thermostat. I live in Florida, and you definitely don't need heat this time of year.
It has not happened in a few weeks (been monitoring)...the only thing I have changed was to turn off the Alexa "AI" which would suggest that things happen to various devices. I also removed the thermostats from the Alexa integration.
Hasn't happened since...but still monitoring.
This thermostat is not integrated with Alexa or anything except Hubitat. I am using it as a battery-only thermostat. I used a multi-meter to check whether it was sending a heating command via its wired interface and it didn't appear to be.
I have decided to add a plausibility check in the next version of my HVAC software, and treat a thermostat as offline if its operating state is not consistent with its reported temperature, setpoint, and mode.