[SOLVED] CT100 ZWave Thermostat Fahrenheit vs Celcius

[davegravy]

Recently I bought a CT100 thermostat and it have it configured and responding via ZWave

The device is detected as a "Standard Thermostat" device template.

When I try to set heating/cooling setpoint temp it seems to interpret values as Fahrenheit even though in webadmin it says setpoint values are Celcius. How can I modify the behavior to allow Celcius values to be sent?

[davegravy]

Anyone?  Is this a case of needing to make a non - generic template specifically for this thermostat?

[sambuca]

There is nothing in the template that decides what unit the temperature is interpreted as. All my devices works as expected (I also use Celsius) and I don't recall having to do anything special.  But I do think some devices has a configuration setting to toggle the unit it interprets values as - you should read the manual for your device.

br,
sambuca

[Marie.O]

I checked the install manual for the device, and it only talks about Fahrenheit. You might want to check with the manufacturer if and how to change between Fahrenheit and Celsius.

[acald]

http://www.connectctc.com/CTC_Support/documents/smart-home/Smart-Thermostat-User-Guide.pdf

See page 5

[davegravy]

There is nothing in the template that decides what unit the temperature is interpreted as. All my devices works as expected (I also use Celsius) and I don't recall having to do anything special.  But I do think some devices has a configuration setting to toggle the unit it interprets values as - you should read the manual for your device.

br,
sambuca

http://www.connectctc.com/CTC_Support/documents/smart-home/Smart-Thermostat-User-Guide.pdf

See page 5

As far as I can tell from the documentation, the device allows you to switch display units but not the units it expects as input via ZWave.

Given this, I assume I'm out of luck until/unless some conversion code gets implemented somewhere in LMCE.

[Marie.O]

Did you check with the manufacturer?

[davegravy]

Did you check with the manufacturer?

Emailed a while ago, waiting to hear back.

[davegravy]

Manufacturer responded by referring me to support for my Zwave controller.

I responded:

Perhaps my question wasn't very clear.

Your thermostat interprets commands sent over Zwave and modifies its settings (example heating termperature setpoint) accordingly. The means by which it interprets those zwave commands is what I am questioning, and is irrespective of the Zwave controller.

The zwave controller manufacturer will not be able to help me with this and will refer me back to you.

Please tell me if there is a way to change the behaviour of the CT100 so that it interprets temperature setpoint changes received via Zwave as degrees Celsius as opposed to degrees Fahrenheit (note that I'm not referring to the display units which is a different matter).

I'm not very knowledgeable about how these devices talk at a low level, but I'm assuming there is no unit (Celsius/Fahrenheit) supplied with setpoint commands by the controller, just a value, and that it's up to the thermostat to interpret it as Celsius or Fahrenheit (obvious design would be to decide this based on the unit that the user has chosen to have displayed on the LCD of the screen).

[davegravy]

Response from manufacturer:

Hi, sorry, but no there is no way to adjust how the thermostat communicates through zwave. If you have any additional questions please don't hesitate to contact us.

So... About translating set point values into Fahrenheit on the LMCE side...

[Marie.O]

Sounds like a feature request.

[davegravy]

Sounds like a feature request.

Created.

http://svn.linuxmce.org/trac/ticket/2264#ticket

[davegravy]

Note that in the send command window (webadmin) for the thermostat temperature is this text

Can be absolute, like 20, 18, etc., or relative, like +2, -2, etc. The temperature is always in degrees celsius, and the application is expected to convert to Fahrenheit if necesssary.

Not sure what "the application" is referring to exactly in this context... if it's LMCE or the thermostat device.

[davegravy]

Thanks to Sambuca for the surprisingly quick feature request fulfilment!

[Marie.O]

Update is in the repository