Fully featured HVAC with modbus device


I have a Nilan Compact P “HVAC” that speaks modbus and I am trying to integrate it with HA.

I can use the climate platform in mobus for this. This also works, but do not have access to all the functions that are available via modbus. E.g. can’t turn the unit on or off or change modes (cool, heat, auto).

So I tried to use the template platform to “build” my own HVAC.
Here, interestingly, unlike the other template integrations, the template platform is not suitable. You can only build a very simple heater from a sensor/switch, but not assign a real device to the HVAC properties.

For MQTT HVAC this seems to work, here the options I need are available. For Modbus unfortunately not.

Did I miss something, or does template somehow work differently here than for other device classes?

I haven’t found anything in HACS that can be used to implement something like this.
To push the entities provided by Modbus again via MQTT to use the MQTT HVAC cannot be really intended as a solution, I think.

Is there a trick to build your own HVAC and use service calls to set and entities to read? Thx for any help!


This may not answer your question but I just started using this to integrate my Waterfurnace geothermal pump locally using modbus. It basically talks to modbus and translate and push everything to MQTT. I then interact with MQTT via Home Assistant. It may be a good starting point if you want to integrate your system with MQTT and modbus.

I agree with you that both MQTT HVAC and Template HVAC should be on the same feature level.

Curious if you’re still using the waterfurance_aurora code? I just set it up and am impressed with all the information it exposes from my HAVC system. However, I don’t see the current temperature and desired temperature in the data available on HA. It appears they are register values 501 and 502 on my system, as they show if I use the command line tool:

aurora_fetch /dev/ttyUSB0 valid

These values don’t make it to MQTT. Any idea on how to access this information? Also are you just using the vertical-stack the guy had on github page or do you have an alternative presentation screen you’re using in HA?

Yes I am still using waterfurnace_aurora. If you need help with it you are better off opening an issue on the github repo but you should look in MQTT to see if the value is exposed there.

I am the one who made the vertical stack config. I no longer use it as I have redesigned my dashboard since.

I opened an issue. Is there something that you might share from your new dashboard?