GoControl ZWave thermostat - half degree increments in Celsius?

Hello all,
I recently swapped out my Nest Thermostat for the GoControl Z-Wave Thermostat GC-TBZ48 (for obvious reasons) and after quickly find -> replace all with the new entity in my automations, etc, was back up and running in no time. I’m connecting my Z-Wave devices through Vera.

Only problem is that after switching the thermostat to celsius, it doesn’t seem to accept 0.5 degree increments. My automation is setting it to 21.5 and it automatically resets to 22, even though the thermostat spec sheet shows it can do 0.5 C increments.

Anyone seen something similar?

Looking online at the manual, I see this:

Set-point Accuracy 1° F (0.5°C), Calibrates to +/- 7°F

Ambient Temperature Display Accuracy 1° F (0.5°C)

They “fudge” their set point accuracy by saying +/- 7 F which they would say is +/- 3.5 C. Technically it is within specification, unfortunately.

I’m a bit confused by what they mean by “calibrates to +/- 7F”

I misread that. I thought they were talking about accuracy. You can calibrate the sensors I believe. Change them +/- 7 F.


from https://products.z-wavealliance.org/products/2370/configs
and https://products.z-wavealliance.org/products/2370

So, what does this mean in terms of setting the thermostat to 0.5 C increments? Seems like HASS sends the half degree value, and then the device sends back that it was set to the nearest integer.

The only places I saw the 0.5 mentioned was for the temperature display & the section I quoted from the specifications.

I think it is worth a call to the manufacturer. You may get lucky and get a real answer.

If you use the buttons on the thermostat, does it adjust by 0.5 C increments?

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Page 18 of its installation manual indicates, when user preference is set to Celsius, it displays temperature in 0.5 increments.


I’ll have to check again when I’m home, but I believe it does adjust by 0.5C increments

Agreed, that’s why I’m confused that I can’t set the thermostat to a 0.5 C temp, like 21.5.

Might also try posting the contents of OZW_Log.txt when you are setting the temperature. It should show you exactly what commands are being sent to the thermostat and their contents.

I’ve connected these through Vera, so likely don’t have the same type of logging available. I’ll have to see what logs are available tonight or on the weekend when I’m able to dig into it.

Let’s take Home Assistant out of the equation for a moment: Can you manually set the thermostat to 21.5? If you cannot then this becomes a different conversation.

Let’s assume you can set it manually. The question becomes: What is the value sent by Home Assistant?

Do you have a means of confirming it sends a zwave command containing 21.5?

Oh, Vera is a completely different story. This could be a limitation of the Vera API. According to the HA Vera climate code, and the pyvera python module, it seems to be using this API method to set the temperature:


Sets the desired setpoint. User serviceId urn:upnp-org:serviceId:TemperatureSetpoint1_Heat for heat and urn:upnp-org:serviceId:TemperatureSetpoint1_Cool for cooling

Arguments: NewCurrentSetpoint(Integer)

NewCurrentSetpoint: An integer value between 0 and 100 specifying the desired heat or cooling setpoint.

If the API truly only accepts “an integer value”, then you are out of luck.

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Ah, well then. Looks like I need to take this up with the pyvera folks. Thanks for digging into that for me, wouldn’t have thought to check there.

Were you ever able to get the half degree increments to work? I have the same thermostat and would like to control it in the same manor.

Honestly, I somehow fried mine and ended up replacing it with a Radio Thermostat CT50. Good luck though, if you’re using Vera and this thermostat, you’ll need to talk to the vera/pyvera folks.