Options for simple underfloor heating control

[julianmclean]

What are my options for a simple electrical switch, controllable by Domoticz, in order to switch on/off an underfloor heating circuit?

Constraints:
* Current setup is RPi running Domoticz with wifi/bluetooth and RFXCOM for 433Mhz
* Lightwave Gen 1 lighting (only mentioning because I have already looked at the Gen 1 heating products - I don't think I can use/control these via Domoticz as they run on 868Mhz and not even sure if Domotics understands the heating protocol? I suspect I *could* use the LW830 3kW inline relay, but this doesn't fit in a 1-gang backbox - the one that does is only rated at 500w)
* Single gang backbox houses current (non-smart) thermostatic switch for underfloor heating - ideally would retro-fit replace with something else in this position

I don't need thermostatic control - merely a wireless switch, ideally installable in a 1 gang backbox, that can handle the heating circuit load and be controllable from Domoticz. All on/off logic will be integrated into existing DZVents Scripting. If it has a manual on/off switch on the device that is a bonus, but not essential.

I have done some searching, but struggling to find anything simple to meet the need!

[Geitje]

You could use a Shelly 1, it's controlable by wifi. You could flash Tasmota, to easily integrate it in Domoticz using MQTT. Or use the Shelly Cloud plugin. You can control the Shelly by using a for example 433Mhz thermometer and a script.

Shelly is rated till 16A. I am not know sure if it is wise to switch such high currents over it as floor heating... Also you probably miss some safety measures a real floor thermostat has. Like having a floor thermostat which switches of when overheating. Probably also a overload protection? And what if the battery of you 433 thermostat gets empty, and the floor heating is not switching off...?

I myself use a Zwave floor heating thermostat from Heat-it. It works great, but is not cheap. Also I think you need new hardware for that (Zwave stick).

[FireWizard]

Hi,

Is Shelly 1 a solution?
Can eventually be flashed with Tasmota.

See: https://www.shelly.si/en/wifi-relays/1- ... 01862.html.

Regards

[julianmclean]

Thanks Geitje and FireWizard for the pointers on the Shelly 1 - not a brand I was familiar with thus far. I could definitely have other use cases for this cheap device if it works ok with Domoticz.

Shelly is rated till 16A. I am not know sure if it is wise to switch such high currents over it as floor heating... Also you probably miss some safety measures a real floor thermostat has. Like having a floor thermostat which switches of when overheating. Probably also a overload protection? And what if the battery of you 433 thermostat gets empty, and the floor heating is not switching off...?

Well...I'm not an electrician, but my understanding of what I currently have (and an admittedly brief chat with an actual electrician) controlling the underfloor heating is basically a relay, which then has has a thermostat (in the device though, which is just outside the bathroom, and NOT actually in the floor itself) and of course some timer programming, etc. So, my take on this is that there can't really be any "safety aspect" in this device. Frankly, the bathroom floor would have to get pretty damn hot before the ambient temp outside the room would trigger a cutoff from the device? So, I accept that my energy bills will be at the behest of my control mechanism switching a relay on/off, but isn't there some other safety mechanism "closer" to the actual underfloor heating circuit? Happy to be told by someone more knowledgeable that I'm talking nonsense here... ;o)

I myself use a Zwave floor heating thermostat from Heat-it. It works great, but is not cheap. Also I think you need new hardware for that (Zwave stick).

WIll also look into this route - I'm not averse to moving forward with Z-wave tech, but as others have mentioned, it's not so prevalent here in the UK thus far.

[yomark]

@Geitje, Shelly's have build in MQTT support in recent firmware's. It works well. So no flashing required for most use cases.

[julianmclean]

It seems my memory was incorrect - current non-smart controller has wired-in thermostat under the floor, which raises a couple of different questions:

• What are my options for a direct replacement - i.e. an underfloor heating controller (that can use underfloor sensor for temp cutoff, etc) but also offers smart functionality for Domoticz integration? I would prefer the simplicity of IP-based control with local API, but can deal with cloud-connection if needed. Apart from setup (e.g. temp cutoff), I don't want to have to deal with some native app!

• Does anyone know how "compatible" the underfloor temp sensors are? i.e. can I buy a new controller and just connect up to the existing underfloor sensor? If not, I'll just have to wait until the bathroom gets overhauled!

[kimot]

My solution....
Floor heating independent thermostat with Domoticz setup.

https://www.youtube.com/watch?v=1ef6tRinOQ4