Zen Thermostat Fan Settings


I have a need where I want to be able to turn the thermostat fan on or off along with my house fan. I added an action for true to change the "Fan setting" to "on" and it works. The fan on the thermostat will turn on.

The problem comes in trying to turn the fan off or more accurately, to "fanAuto". I can select "auto" in the "Fan setting", the FanMode never returns back to fanAuto. I have to go into the device itself and select the "Fan Auto" button.

I setup a quick test RM with a virtual switch where on was true and the fan was set to "on" and off was false and "auto". The fan turns on, but won't return back to fanAuto. Am I doing something wrong? There are only two options for the "Fan setting."


I can confirm that there is a "feature" in RM causing this problem. Ironically, this "feature" has been there from the very beginning, dating back to the ST days for RM. The origin of this is a documentation "feature" in the ST capabilities documentation -- the reference used to implement thermostats in RM. In that documentation it describes the two commands for SetThermostatFanMode as "on" and "auto". For the Zen thermostat the two commands implemented are "on" and "fanAuto". I only have a Zen to test with. So, RM will be updated to use "fanAuto" instead of "auto", and I have successfully tested this with the Zen.

I don't know which is correct.

What thermostat are you using?

I am also using a Zen thermostat. I bought it after getting the Hubitat to replace my Nest to keep the ideology of moving as much away from the cloud as possible. Plus it looks cool. Here is the rule I'm testing with:

Is there a way to limit the commands exposed for thermostats to just the supported ones? I have fan and cooling/auto settings for my baseboard thermostats with neither fan nor cooling capabilities.

I notice the zen thermostat uses raw hex communications for modes and control. Is that code available somewhere to view? I want to try to get my Sinope stats local control working but I need a base code of similar function to build from.

Ah, it’s an API from smartthings, that’s fine. I’ll grab what I need from there.

I think you can find the Zen DTH for ST in the ST public repo.

One last question regarding the Zen thermostat. Will there be a way to manage it via Alexa soon?

Thank you for changing the thermostat code for the fan control. It works! Do you have a timeline when Alexa will be able to control the Zen Thermostat?

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