EMS bus support UK

edited October 2022 in General Questions & Topics

After purchasing a V3+ wireless thermostat kit 10 days ago and being disapointed in it not having EMS bus support I now come accross this you tube video stating that it is now going to be re-instated

Is there likely to be any chance of tado upgrading recent purchases, and if not where can you purchase the newer controllers and be shure that it has EMS bus support



  • It’s not really an upgrade, it’s a different model. You can buy it here (when it’s in stock) https://uk.installers-shop.tado.com/products/wireless-smart-thermostat-starter-kit-v3-eu-version

    You should be able to return your current kit if it was only bought 10 days ago.
  • rjgw
    edited October 2022
  • Yes, you could replace your existing wireless receiver.
  • Ditsy
    Ditsy ✭✭✭

    I also saw that video. Our Worcester 42 CDI Classic Boiler is capable of modulation. The Tado system has been installed for a few years. We're using a Tado Extension wired to the boiler, and a wireless thermostat plus TRVs.

    How do I:

    1. Check whether we already have the older extension that is capable of modulating? If we don't, which item would we need to purchase to sort this out? Is there a trade-in scheme?
    2. I've been back through the extension instructions in the normal Tado app (not the installer app) and it seems to be set up as Tado advised. If the extension is capable of modulation how do I check whether it's set up correctly? What should the wires look like? I've checked the Tado help section and there is almost nothing on this topic despite the assurances on the comments for that video that documentation will be added. I've seen a number of references on different threads and forums to two wires and we have more than two connected, so I'm suspecting it's not set up for modulation.

    Tado: please sort this out. It's really unclear what version of components we have, what we need, how much it may cost to upgrade, and since you downgraded support to chat only, it's extremely painful to try and get any help.

  • Are you addressing this to the community forum or tado support? If you want to contact support you will need to do it through the live chat.

    If you have an extension kit rather than the newer wireless receiver it will have digital connections.

    If you’re using digital connections in the extension kit then the wires will be connected to the sockets marked + and -. You can also download the Tado pro app and scan your bridge’s qr code and it should tell you how your system is installed.
  • Ditsy
    Ditsy ✭✭✭
    edited November 2022

    Thanks for your help! Tado sometimes answer on community threads, and I dred trying to navigate Tado support so hoping to obtain answers here and add to the voices letting them know that their communication on this subject needs to be much clearer.

    On the video Tado seem to be referencing silent changes to an existing model. Our extension kit was purchased in 2019 which seems to be a key date for this issue. I'm trying to understand how I know whether the model we purchased was before they removed the functionality or after they did. I'm not imagining I'll switch this over myself, I'm trying to find out whether I need to purchase a new component before I arrange for someone to sort the wiring out, otherwise I'll probably get charged for two visits.

    I've located a Tado installation manual online called "230 V Relay Installations" that I think shows the same wiring as we currently have (there is no legend for the diagram markings). We have + and - connectors but nothing connected to them, and a yellow tag hanging from them stating "max 36V DC". Does this mean the extension can modulate I just need the wiring sorted out?

    Is there a specialised lead / cables / connector for the + and - connectors that I need to obtain or ensure a tradesperson brings with them?

  • Ditsy; yours does indeed have the functionality but it is not set up for modulation at the moment. You would need to connect a 2 wire connection to the Opentherm/ebus connections within the boiler to the -/+ connections are the right of your extendeder there. It doesn't matter which way the wires go but it's very important you don't put any wire carrying 230v into the +/- on the tado extender as these are only meant to carry 5v I think.
  • johnnyp78
    johnnyp78 ✭✭✭
    edited November 2022
    This is the manual for installing the extension kit with digital connections. You may find it reconfigures itself, if not there are instructions here for how to set it to opentherm/ebus (I would check with Tado what your boiler supports) https://cdn.brandfolder.io/607DGEMS/as/bxgtx5kghgjrbcs4m68kqch/Extension_Kit_Manual_-_Low_Voltage_Digital_Installations.pdf
  • Ditsy
    Ditsy ✭✭✭
    edited November 2022

    Thanks both for your help.

    We switched from Hive to Tado and followed the instructions we were sent. I wonder how many others would be able to use modulation if they just altered the connections. Tado should audit their customer data and let customers know where there are options like this that haven't been utilised. Maybe it should be part of the Energy IQ app section.

  • Hi Ditsy. I think you may have done what I'm trying to do.

    Did you get the Wired Tado V3+ connected to your Worcester combi via EMS bus?

    If so, what settings did you use for setup as per Johnny's guide above e.g. D05, D07 etc?


  • Ditsy
    Ditsy ✭✭✭
    edited November 2022

    @ColdTattie I haven't had the wiring altered yet. I did discover that if you access the Tado app (not the installer app), select Settings -> Rooms & Devices -> Extension Kit -> Installation Instructions -> Change Selection, you can enter your boiler model and get the instructions you need immediately (back in 2019 there was a longer process to get the instructions). I stepped through those instructions to see what was involved, and at the end without prompting or informing me the app must have triggered the installation configuration. Given our heating is still wired the wrong way for the EMS bus, that broke our existing setup and when I figured out what had happened I manually overrode the configuration via the wireless thermostat installer menu option so it's working again.

    So, there's a good chance if you follow those steps you won't need to manually set the configuration at all, it should just work. However, if not, as I understand it, you'll need the HT-Bus section on page 30 of the document that @johnnyp78 previously linked.

    D05 and D07 are codes that relate to the Valliant eBus. Page 36 of the manual indicates that D17 and D18 codes relate to the HT-Bus. D17 for systems without a FW controller, and D18 for systems with a FW controller. FW controllers appear to be weather compensation controllers that may already be connected to the boilers.

  • Thanks @Ditsy. It has been torture trying to get Tado Support to confirm whether it speaks EMS or not but in a round about way they say it does.

  • Da_g_prof
    edited November 2022
    Worcester replied.

    Thank you for your enquiry.

    The only controls that can modulate the appliance (Greenstar 30cdi combi) are Bosch EMS controls, connecting a Tado will not work in the same way and may also cause damage to the process control board.

    We would advise to only use a Tado as a 230v on/off connection.

    Best Regards,

    Technical Support
    Worcester, Bosch Group
  • I could be completely wrong about this but I don’t think that’s true. Tado has reverse engineered the various ebus systems, including ems, so it can work “in the same way”. Worcester Bosch could just implement Opentherm, like it’s forced to in the Netherlands, but then would have to allow other manufacturers to connect to its boiler rather than using a proprietary protocol to keep out competitors.
  • I have a sneaky feeling that Worcester may be being a little disingenuous with that reply. I suppose unless Tado does everything that worcesters controls do, in exactly the same manner, then their reply is accurate. Doesn’t mean that Tado won’t work though.

  • So should I still make a gamble and buy a EU version of the receiver and give it a shot?
  • That’s down to you. I’m not sure what the return conditions are if you’ve installed it and it doesn’t work with your boiler’s digital connection. Will definitely work on relay though.
  • if you have a Worcester Bosch system don't bother they don't communicate to be able to modulate

  • Notascoobie
    edited November 2022
    @Neelyt, that's not the case. I have an EU extension kit connected to the digital comms connections in a Worcester 38cdi, and it modulates just fine. And that's in the UK.
  • Interesting points. I guess I was also trying to future proof but at this stage, I might just buy the UK version and if / when I buy a new boiler consider upgrading also the receiver.
  • @Neelyt I think it really depends on the model and the serial number even (year of production).
  • Ditsy
    Ditsy ✭✭✭
    edited November 2022

    @ColdTattie In our boiler installation manual there's an electrical section with a diagram that shows "EMS BUS contacts" which I'm hoping means ours can be connected. When I fed our specific boiler model into the Tado app, it supplied digital connection instructions, so it seems Tado also think it can be connected satisfactorily. Which is interesting because back in 2019 they supplied relay connection instructions, so something happened between then and now to change their thinking. Customer data maybe?

    @Da_g_prof thanks for the input. My experience of the Worcester Bosch support team doesn't lead me to put a huge amount of faith in them I'm afraid. When our boiler was new I spent a ridiculous amount of time trying to get them to clarify some configuration options relating to the Wave Controller. I'm inclined to agree with @johnnyp78 that the response may not be correct.

    I'll post again when I get ours up and running (or find it won't work) as it might help others.

  • Latest WB 4000 bomb boiler

  • Ditsy
    Ditsy ✭✭✭
    edited November 2022

    I think people need to be quite careful about specifying their whole Worcester Bosch boiler model name. Looking at that list, there are "Greenstar CDi Classic" and "Greenstar CDi Compact" models that Tado indicates a digital connection is supported for, then there are "Greenstar CDi Conventional" and "Greenstar CDi Classic Regular" model numbers that are listed as not supported. So when someone refers to a "28 CDi" do they mean one of the ones that Tado states is supported, or are they referring to one of the models that Tado states is not supported?

  • @Ditsy thanks for the above. I fully agree with you that precise model specification is important. Unfortunately at the moment, tado provides installation information after you buy a product. When I tried the professional installation software they didn't list my model.
  • Where can you find this compatibility list please Ditsy?
  • Ah I see, just using model-selector.tado.com and scanning the bride.

    I get: Recommended connection type
    Digital - HT-Bus (D17)

    So I guess we can use the wired or EU wireless and have modulation.
  • Its a amazing Tado removed BUS connection this makes it same as my Hive only reason I looked into Tado is because of modulation. All new boilers have modulation and I don't want a simple on or off system in 2023!

  • I personally think that most of the latest generation of boilers can do as much as a tado style 'add on" smart system does.....and probably more if they have a Weather Compensation feature.
    Surely tado has now fallen behind with its "smart" technology.
  • vmguru
    edited January 23

    I was thinking the same thing, why on earth would Tado remove ebus features from the standard product being sold in places like screwfix this dumbs down the thermostat. All new boilers want modulation. All manufacturer controls by Worcester Bosch, Vaillant have modulation built into their controllers makes no sense to use a Tado then? perhaps I am missing something?