Thermostat Node

  • I am looking to use a “node” that will report as a thermostat to domoticz. This thermostat node will have a relay connected to it which turns on/off the hvac system. How can I make this happen?

  • It all depends on your furnace and how it is wired. Check your existing thermostat too and see how that is wired.Many furnaces in the US run on 24VAC. Once you know your wiring to your furnace, it should be as simple as putting relays between the common line (usually blue) and the heating (usually white) and air conditioning (usually yellow) lines. It's a little more complicated for multi-stage systems because you have to deal with 2 or 3 heating and/or cooling stages.

  • thank you, regarding the wiring, I don't have any issues. It is the programming that I am concerned about. Where do I find an example for the thermostat-node, which will be sending info to the relay-node?

    Thank you.

  • @karelsmits I am assuming that you are talking the relay that turns the furnace on and off. Wouldn't you have the relay on the same node as the temp sensor? Do you also have cooling/AC on your furnace? If so, you will need to take that into account.

  • The temperature sensor is connected to a different node in a different place in the center of the house. I want the relay-node to act by instructions from the thermostat(temperature)-node. (I would hook the whole system up to Domoticz).

  • @karelsmits So essentially, you want a relay node that will act as a thermostat node and accept temperature information from a different node. How then would you set your temperature set points?

    The relay/thermostat node will have to handle the temperature set points with some built in hysteresis, and probably some adjustable minimum off time (MOT) and minimum run time (MRT) to prevent constant cycling of the furnace/heating system. If you have AC on the furnace, or ever plan to add it, that will need to be factored in as well.If you have AC, then you will need two relays.

    When I put my setup together, I was just creating a bridge to an existing RS485 controlled thermostat. I didn't create a fully functional thermostat node. I am not sure if anyone out there has created a functional MySensors thermostat node as of yet. If you plan on doing it yourself, there is a lot of factors you need to take into account before coding such a thing.

  • @karelsmits
    Use "events" in Domoticz.
    Check temperature from your temperature node and according its value set Heating or Cooling.
    You can choose Bloclky, LUA or dzVents in Domoticz.
    But it is hard to obtain any relevant information about getting data from Domoticz to thermostat
    -setpoint in MySensors for example.
    I need quick solution now, so I am using ESPEasy for my floor heating thermostat.
    I prefer regulate temperature "outside" of Domoticz, so it works even when domoticz ( raspberry) is down.
    I use temp. sensor on the same node like relay, but it is not problem send temperature from other node or send command for heating from Domoticz.
    Look here:

  • @kimot
    going to check it out, it looks very good.
    thanks a lot

  • Plugin Developer

    How did it go?

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