I have a Radio Thermostat CT101 Z-Wave thermostat, which has been working well in my HA system for several years. I recently added a couple of “booster fan vents” to rooms at the far end of the HVAC system, and I wanted to control them through HA. The CT101 doesn’t report any switch entities – at least, not through my Vera Edge – so I’ve been using the difference between set_temperature and actual_temperature to control whether the fans are on or off. The problem is, while the CT101 can receive half-degree set-point changes, it can’t report similar status changes. Making things worse, it reports integers so 74.5F and 74.0F, for example, both report as “74F,” meaning that booster fans shut off early when in AC mode. (It just happens to work OK in Heat mode because the rounding is in the right direction.)
Research online shows that this “feature” seems to be true of several other Radio Thermostat models, so I suspect that it carries across their product line. I’m thinking of replacing the CT101, but I want to make sure the next thermostat doesn’t have this issue. Any recommendations?
Do you have a temperature sensor in the room that has the booster fans. You could create a generic thermostat from the temperature sensor to control the booster fan in each room. I have ecobee, and they have the same problem but are not local API either. Venstar have same issue but do have local API.
@AllHailJ Thanks for the reply. Yeah, I guess I could put a temperature sensor in the room, but all I really need to know is, did the HVAC fan turn on or off? I’m not really trying to set up a second set point, but just to coordinate the two fans.
Disappointing about the Ecobee and Venstar units: I was hoping that if I spent a little more $$ things might get fixed, but everyone seems to treat these things as fairly dumb devices – a thermostat is “a thing that changes temperatures,” simply reporting the set point and current value. I was looking at the data that the CT101 provides via Z-Wave, and it’s not even accurate! (ex: the A/C is off right now, but the Fan Status reports as “On.”)
The venstar has additional fan control that may help in your situation. They call it smart fan but I don’t know it you can control from the API. It is available on their more expensive thermostats T7900
This should be reported by the z-wave entity, but is saved in HA as an attribute rather than a state.
I have a Radio Thermostat CT30 using z-wave, and I activate my booster fans based on the fan_state and hvac_action attributes of the climate entity to know whether the fan is running, or the hvac is heating/cooling, respectively. Does the Vera not report this to HA? Check under Developer Tools → States → Set State.
Unfortunately, no: Vera does not report fan_state or hvac_action. It has a function called “Fan Status” (on the Vera side), but as I mentioned earlier, it’s not even reporting properly – with the A/C set point above the room temp (so the A/C is off), the Fan Status = On.
The only thing that might be useful to me is Precision: if I can set it o 1.0 and it stays, I could live with a thermostat that only reports Fahrenheit degrees, and that would eliminate the roundoff. We’ll see if it works …
I was looking at the data that the CT101 provides via Z-Wave, and it’s not even accurate! (ex: the A/C is off right now, but the Fan Status reports as “On.”)
