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Support current and more recent Vaillant eBus controllers

Tado asserts the benefits of modulating boiler control and touts compatibility with Valiant and eBus. However, the reality is rather grim. It turns out that as of 2019-03 eBus is only supported in these scenarios using the now discontinued VR65 controller. No other controllers are supported (VR66 for example). This means that tado has very limited Vaillant/eBus compatibility and most will be forced to use only binary switched live controls, and not benefit from the additional comfort and efficiency provided by modulated control.

Please can we see some efforts to keep pace with what I imagine is a relatively slow moving target. It is sad that in 2019 one of the leading smart thermostats constrains home owners into choosing outmoded and inefficient control methods.

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  • Hi,

    Unfortunately we have to reverse-engineer most interfaces from scratch as not all boiler manufacturers are interested in a partnership or in assisting an alternative control device to their own, hence it can take time to do so properly (assuming that there are no legal issues preventing us from doing so).

    Best regards,


  • @teabot @Frank

    I hope Tado do eventually succeed in reverse engineering the new VR66 controller.

    In the meantime another possible but less than ideal solution might be to use the Valiant VR33 OpenTherm conversion module. See - https://wifithermostaten.nl/vaillant-opentherm-module-vr33.html

    This is actually an official Valiant part but is intended only for sale in the Netherlands which may have a local requirement for the use of OpenTherm compatible products.

    Tado is as far as I can tell unique in supporting both eBus and OpenTherm protocols - most other smart thermostats support either OpenTherm and on/off control but not eBus, for example Nest v3 supports OpenTherm but not eBus.

    However be warned even though the above VR33 part is a genuine Valiant part and even if you get it fitted by an approved engineer Valiant will consider this to invalidate any warranty - at least here in the UK.

    Tado regard eBus as being superior to OpenTherm but OpenTherm does still give you the most important benefit of modulated control.

    This news however might lend additional weight to my plans to get a Worcester Bosch boiler instead.

  • JurianJurian | Admin

    @teabot @jelockwood

    As teabot already pointed out, we can control "system boilers" using Vaillant eBus when you use the VR65 mixing module. You might still be able to pick up this module from the 2nd hand market.

    An alternative might also be to go for the "Glowworm Smart Wiring Centre 2". We can control that box using Glowworm eBUS and this would allow you to have a system boiler that is being controlled in a modulating way.

    Alternatively, you can always opt to for a combi boiler from a brand where we support the digital interface: https://support.tado.com/hc/en-gb/articles/208016186-Is-tado-compatible-with-my-boiler-

  • @Jurian I have a multi-zone system with a combi boiler as the attached diagram. Will 2 tado room thermostats work in this configuration with Glow-worm smart wiring centre 2?

  • Got to add me the line of the inquiry if anyone has had success in using the smart-wiring centre on a vaillant or similar system? Got my hand of a v3 Tado start-up set but having a Protherm Gepard gas combi-boiler, I am reluctant to miss out on the possibility to use the modulation-capacity of the system. The alternative is to get a Vsmart Vaillant control or as it is marketed here, the Migo thermostat, with its limited functions, but profiting from its more energy-efficiency.

    regards from CZ, mirrormurr

  • I was initially puzzled by Jurian's suggestion to use the Glowworm wiring centre since Glowworm is a different brand and one might think the wiring centre was therefore for use only with Glowworm boilers and not Vaillant boilers which was the original query.

    However for anyone else also puzzled by this Glowworm was purchased by Vaillant in 2001. I am still not 100% convinced this means the Glowworm Smart Wiring Centre 2 would work with a Vaillant boiler but it increases the chances it would. It would be a way to use a Glowworm boiler with a Tado Smart Thermostat.

    I found a more complete copy of the manual for the Glowworm Wiring Centre 2 here - https://manualzz.com/doc/13815818/smart-wiring-centre-installation-and-user-s-manual

    It still raises other concerns, apart from it looking a lot more complex I would have thought it was possible it might result in any warranty being invalidated. It is already the case that fitting a Vaillant VR33 module to convert a Vaillant boiler from eBus to OpenTherm invalidates the warranty and remember this is a genuine Vaillant part and far easier to fit.

    In my case I am considering a Worcester Bosch boiler instead which like Vaillant uses eBus but unlike Vaillant is apparently still supported by Tado but others might want to look at other brands which support OpenTherm natively e.g. Baxi.

  • After numerous contact with customer support with the confirmation of the compatibility with the eBus system, I took the chance and had the Tado installed for our small Vaillant boiler, the Protherm Gepard, and can confirm the inability of the Tado system to be controlling the temperature of the hot-water and the radiator-temperature.

    Basically, Tado is just an expensive remote on-off switch...-guess I should have gone for Protherms own products, namely the Vsmart or as its called here, the Migo Thermostat. *sigh*

  • Is there any news on support for the Vaillant VR66? I'm "unfortunate" enough to have one fitted in my new house. Or is there a list or someway I can be notified of updates?

  • @AdrianC @mirrormurr

    I fortunately have not yet bought a new boiler but all this is convincing me to go for Worcester Bosch rather than Vaillant.

    I think your best option is as previously suggested by Tado to try and find an older VR65 controller module and get that fitted to 'downgrade' your boiler. I did a quick search on eBay and there seem to be a number listed.

    It should be noted there is the potential for a similar compatibility issue with Worcester Bosch. British Gas make a module for Worcester Bosch boilers called Boiler IQ. This module sends diagnostic information to British Gas over the Internet. However if you have this fitted it at a minimum prevents Tado's own diagnostic reporting and might also prevent eBus working altogether.

    Hive an alternative smart thermostat solution has been designed so it can work alongside Boiler IQ. It does this by accessing British Gas' cloud service and downloading the diagnostic information from that. I believe Hive is actually owned by British Gas.

    This is a shame as I might have gone for the Boiler IQ module/service. Thankfully I discovered this in advance.

  • For those of you interested, I’m able to control my Vaillant boiler from Tado. A bit complex to setup but work perfectly...

    in a nutshell:

    • My Tado thermostat is not wired to my Vaillant boiler
    • I’ve setup a node-red flow that periodically check, via Tado API, the requested temperature in each of my rooms vs the current temperature of that room. So I got a delta per room. My script takes note of the highest delta.
    • then my flow talks to my Vaillant boiler using ebusd ruining on my RPI - it “adds” the highest delta to the current temperature in the room where the Vaillant thermostat stands: this causes the boiler to turn on.


    • Room 1: living room with Vaillant thermostat and Tado thermostat and valves
    • Room 2: bathroom with Tado valves
    • Temp in Room 1: 20, asked temp: 20 so delta is 0
    • Temp in Room 2: 18, asked temp: 22 so delta is 4
    • Therefore highest delta is 4
    • Then I take the temperature of the room where the Vaillant thermostat is (20), add the highest delta (4). This gives 24; then I instruct Vaillant boiler that my desired temp is 24.
    • every 30 seconds, routine is executed again


    • Works with all Vaillant equipment supported by ebusd
    • Reliable: have been using it for months without any issue
    • Benefits from the Vaillant regulation


    • If Tado turns down their API, I have a serious issue :)

    if anyone is interested, I could take some time and write a tutorial...

  • @beetlejuice

    Congratulations. Your effort goes beyond my desire or knowledge, it does however sound like ebusd understands or at least better understands Vaillant's variety of eBus protocol than Tado do.

    This would suggest it might be worth Tado studying the implementation in ebusd for hints on how to resolve their compatibility issue.

    For the benefit of Tado you should look at the following links -

  • I have bad experience with the Tado system

    I have Tado connected to a Vaillant burner for central heating with radiators and I monitor the communication between the Tado system and the burner with ebusd - many thanks to john30 for his nice software.

    All Tado is doing is switching the old thermostat on and off and setting the flow temperature. Their control strategy is actually very crappy :

    • Tado sets the flow temperature way too high - up to 70° when outside temperature is 10°. Their claim to save energy is very unrealistic with this control scheme. Good for comfort, bad for the wallet and the planet.
    • Tado often (daily) asks heat from the burner while closing all the radiators. On occasion (monthly) my burner makes a very weird loud noise - I suspect cavitation in the circulation pump - so that I have to turn it off and on again. Never had that before the Tado system.
    • Swing in room temperature is high, I see overshoots of up to 1° over the set temperature
    • The systems is non-learning, they actually use a simple PID algorithm.

    The thermostats and the app looks nice, but that's all there is to Tado. Nice branding and marketing, but lousy engineering. They don't deliver the claims they make. Having to pay 2,5€ extra for basic geofencing on/off on top of an already expensive installation is a flat out rip-off.

    My advise : don't buy Tado !

  • @stefaanv

    I can't find the forum articles right now I read some and they sound applicable to your situation.

    1. I recall reading that the Vaillant does not advertise the max/target flow temperature to the Tado during initial setup and hence the Tado defaults to an excessive value but in theory over time should learn a better value. This if true would be the fault of Vaillant, indeed I believe the article also said this happened with other brands of thermostat and that the discussion was that Vaillant were not properly implementing the protocol.
    2. Having read the above I contacted Tado about this - more specifically about Worcester Bosch boilers. They said that during initial setup of the Tado it is possible to manually enter an initial target flow temperature but this cannot later be changed. (I would assume that Tado would again 'learn' a better value during continued operation.)

    I am puzzled that if all your TRVs are reporting they are satisfied that your boiler is being turned on. I can only conclude this is because modulated control is 'working' in that it is calling for heat to prevent temperatures dropping too low as there is always a lag. So this could be correct behaviour as long as it does not result in rooms becoming excessively warm. I presume you have also taken in to consideration any Tado Smart Thermostat(s) as well as TRVs as if a Smart Thermostat wants heat then they would obviously have to be obeyed.

  • Folks, I live in the UK and have a Vaillant EcoTec 831 combi boiler (installed over 15 years ago). A few year ago i upgraded the basic thermostat/timer with a Vaillant wireless modulating controller (VR470F) with weather compensation and eBUS modulation. I have asked via the TADO support (ticket 1048047) if my boiler/thermostat combination is eBUS compliant. Ignacio in support replied and said it would work with my setup and all i need is the Tado thermostat and extension kit. Having read the thread here I not entirely convinced it is simple as that. My setup has a Vaillant radio unit that pushes into the main control facia of the boiler using a three pin header interconnect, which talks to a wireless battery powered thermostat/timer.

    My question is, can I just connect the Tado extension unit to my boiler motherboard eBUS terminals and hey presto! I have full control of my boiler including flame modulation like the old Vaillant controller?

  • @Mazza

    Tado would obviously be the best source for a definitive answer but I would expect that if you leave your current weather compensation controller connected this will conflict with Tado. I do seem to recall comments in other forums that weather compensators do cause conflicts - not only with Tado. Similarly if there is some other timer connected this will conflict with Tado's control. Once these are disconnected then I would expect you connect the Tado Extension unit to the eBus terminals.

    What is also worth checking is to see if you can spot a VR65 or VR66 or VR33 module inside your boiler. The VR65 is an eBus controller that should be compatible with Tado. (As much as it can be.) The VR66 is the newer eBus controller which Tado is not compatible with. The VR33 is an OpenTherm to eBus converter which is normally only used in The Netherlands but if present then Tado would be compatible with it and would use OpenTherm rather than eBus.

    Note: As mentioned weather compensation modules do cause a conflict - not only in Vaillant boilers. For this reason smart thermostats use Internet accessed weather information to perform the same function based on your post code. However you still need to remove the weather compensation module as otherwise both it and the smart thermostat 'fight' each other. I have suggested Tado add support for the Netatmo smart weather station as a local weather source.

  • @jelockwood. thanks for the advice. TADO support replied back. I just wire the extension unit directly into the eBUS on the motherboard and it should work fine. fingers cross. I will reply back on here on how it went.

  • Watching this with interest - I've just purchased Tado thermostat & extension to connect to a Vaillant ECOtec 831 like @Mazza and was expecting proportional control, and some degree of 'smart' control with a 'smart thermostat' so we will see.

    I'd say @beetlejuice is on the right track though it's not someting that everyone can do.

  • I can confirm that an 11/2019 Tado 3+ does apply modulated control to a U.K. Vaillant EcoTEC+ 831 boiler.

    The Tado requests an output temperature of the boiler (as seen in the boiler diagnostic display), which does vary depending on current/required temperatures.

    That's great, though I did ask technical support if it did actually do this, and didn't get a reply.

  • I agree with EdGi.

    Recently installed (September 2020) a Tado V3+ to a Vaillant ecoTEC Plus 838 using a wired eBus connection from the thermostat straight into the boiler. It's a UK boiler, just about 2 years old. The thermostat is running firmware version 67.2.

    The Tado modulates the boiler output flow temperature as required. As the weather is still mild, there is a low heating demand and I've seen flow temperatures (on the boiler display) in the high 20s-low 30s Celsius.

    Incidentally, the Tado replaces a Vaillant VRC700f (wireless thermostat with wireless outside temperature sensor) which was an utter piece of junk, in both basic function and performance. So far the Tado is an enormous improvement. I'll see how it performs when the weather gets colder.

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