Just getting started with all of this and starting to work on some details. I have a Honeywell T6 Pro Thermostat (the only one I could find that handled an external sensor) that is setup in my HE using the generic driver per some other posts I have seen. There is a Fan Circulate button in the commands and it words, but in the Current States list the supportedThermostateFanMods only lists Auto and on, so on my dashboard, it doesn't give me the option to put it in circulate mode. Is there a way to add the circulate option to the supported modes?
Not that I know of. However, it is pretty easy to get a tile next to your thermostat tile that controls the fan circulate mode. To do so, create a virtual switch; in my example, I've called it Fan Circulate. Then create a rule like the one below:
Finally create a Dashboard tile for the Fan Circulate switch. When you turn it on, it switches on fanCirculate mode on the thermostat, and when its turned off, it switches to fanAuto mode.
Hope this helps.
Edit - In rule machine, choose "Run Custom Action", and then select your Honeywell T6 Pro thermostat as the device. It will expose fanCirculate() and fanAuto() as custom actions.