Success with linking electric underfloor heating?

Tado_or_not_Tado

Has anyone had any success with linking electric underfloor heating with Tado?

In general Tado does not seem to support connectivity with electric underfloor heating, but does point to Is tado° compatible with electric heating systems? which in turn points to Manual for Professional Installers, implying that it is at least possible (as a non- electrical/heating professional, these guides don't tell me much).

I have a ProgramaSTAT TPT44 controlling electric underfloor heating in two rooms (switch capability: 16A resistive, 3A inductive), and would like to link this into the Tado home system. The underfloor heating controllers are not easy/practical to adjust on the fly, and it generally we're wasting energy when no one is at home without Tado's one-touch 'home' and 'away' modes (or geofencing).

Having a 'hybrid' smart Tado and manual underfloor heating setup is not ideal, and greatly diminishes Tado's value for me :(

I would love to hear if anyone has been able to successfully integrate electric underfloor heating (of any manufacturer), and how you achieved it!

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My specific underfloor heating controller FWIW

robgratt

Does Tado sell a low voltage thermostat that could be used to switch a suitable 240v relay?
This thermostat could then be integrated with the other devices that Tado controls.

adeward

I posted my DIY guide to achieving this on another thread a few days back, but I'll add it here. It's entirely at your risk, and you'd need to check into your own local regulations and hire a competent electrician etc etc, but I believe this to be a (slightly cumbersome) solution. It gets around the 3A limit of the Smart Thermostat by driving a secondary relay (ie. a 240V contactor), which then feeds a higher current to a simpler UFH thermostat (which provides the safety cutoff using the underfloor probe). So it's 3 devices instead of 1, but you can hide the 2 non-tado devices out of sight if done correctly.

I came up with this solution after tado customer support suggested it might be possible using a secondary relay, and used various other suggestions from other forum comments, etc.

My hope is that one day tado decide to make a dedicated electric UFH thermostat, since it is a bit crazy they don't support it.

Underfloor electric heating circuit with tado smart thermostat.pdf

spotty

very interesting, I have the same problem having connected the additional wired TADO to my TR3100 source cables and disconnecting the floor thermostat Nothing happens! Did not know about the max current rule! Looking at the diagram will it control using the air temperature sensor in the tado even though the floor thermostat is in place?

spotty

Thanks adeward, that works perfectly! I bought the manual thermostat off Amazon and the rest from my local electrical supplier. Got an electrician to wire it up and it looks neat inside a kitchen cupboard. I set the underfloor thermostat to 25 deg, and the Tado to 23 as its next to the boiler and now I can have the underfloor heating on whenever I want.

MaxW

@adeward Thank you for putting together the above diagram! I have a related question, and I wondered if you might be able to help.

The positioning of my current electric underfloor heating thermostat is not ideal for mounting the tado thermostat as it would place the thermostat above a kitchen worktop which would not accurately reflect the temperature in the room. It occurs to me that it might be possible to replace the thermostat in your setup with a wireless receiver (https://uk.shop.tado.com/products/wireless-receiver) and then pair that with a wireless thermostat that could be positioned anywhere in the room. The issue is that the wireless receiver is mains powered, so while I can easily see how the communcation cables would connect, do you know if it would be possible to simply wire the mains supply that would be going to the relay in to the thermostat as well?

I've recreated your diagram as I think it would need to be to accomodate my proposal:

https://imgur.com/yg4dwSK

philtrick

Just to add my two cents worth. I've got a wet UFH heating system downstairs and an upstairs bathroom with electric UFH. The downstairs is all controlled using TADO.

The upstairs UFH has a separate Harmoni 25 controller (not smart!) with a floor temp sensor. Obviously there's no way to use the external sensor with TADO. I experimented a bit and found if I put the Harmoni controller into a mode were it just uses the floor sensor (mode 2), if you disconnect the floor sensor the controller stops the heating and displays 'E2'. Reconnect the sensor and it resumes working.

So perhaps an inelegant solution- but I've connected the TADO relay so it disconnects the sensor from the Harmoni when I don't want the UFH on. I've set the Harmoni controller to always be on at 26c FT (Floor Temp). Also I've set the TADO system so this controller does not call for heat from the main LPG boiler.

So as a summary the Harmoni controller just sets the floor temp. The TADO turns the heating on and off at set times. I've set the TADO temp for on times so it should not trigger in the summer. An added benefit is the TADO doesn't come on when we're away from the house.

Sorry no diagram- I don't have time.

jakubkasparekcz

I confirm that the scheme inserted here by user @adeward works. 🎉🎉

Today I wired my electric underfloor heater according to his instructions using a switched relay. 

Thanks a lot for this tutorial.