I have about a dozen of these thermostats that I bought on ebay, and I can reliably get them to "reset" themselves:
- Set a set-point manually on the thermostat (eg. Heat @ 70)
- Set a set-point through Z-Wave (eg. Heat @ 69)
After about a day the thermostat will reset to what you manually set (Heat @ 70). This happens with all combinations of power (C-Wire only, C-Wire + battery, battery only).
I ended up buying a Vivint control panel to check if the thermostats behave the same way when you set the temperature through the Vivint hub, and the good news is that they don't. When the Vivint hub sets the temperature, the temperature stays set.... (and it's not something that the hub constantly sets because I've unplugged and powered off the hub after setting the thermostat temperature).
I've run a zniffer with the Vivint hub (uploaded here: https://filebin.net/tks6xa7r94iy7hjb/vivint.zlf?t=pgfu4wlz) but it doesn't seem to be doing anything too special...
Will try to replicate exactly what the hub does, and see how the thermostat behaves...
