Tado to Worcester Bosch GreenStar 30i Digital Interface EMS Connection Bus (Working Setup Attached)

edited November 2020 in Getting started

Hi below is a working setup for a Worcester Bosch GreenStar 30i Combi Boiler using the Digital Interface EMS Connection to a seperate wireless tado thermostat in another room

I hope others find it useful

Basically I removed my old Hive connection and receiver altogether from the boiler before i started on setting up Tado

I also had add a link connection from White Live out (L) in Boiler to Yellow Radiator connection (LR) - shown in pic

Then wire EMS connection as attached into specific slot in boiler (note the sticky labels on the boiler dont really line up with the connectors so be careful)

Wire up above conection to tado Extension Kit as shown and (move yellow jumper to Number1 on Extention kit) mines was loose from new so double check it

Picture attached shows my working setup - Hot Water is in Eco mode (does anyone use Preheat nowadays)

Mind you It wasnt easy getting their - 2 days of me emailing Tado Support , telling them i had a existing Hive connection and their website then sets you upto use the on/off method by using the hive wiring which means no modulation.

So they further point me to type greenstar 30i and its incomplete as they the guide is missing info regarding the missing link Live Out to LR TAP as mentioned above

Some notes on the two links in a new worcester boiler might help other setups

When the boiler is new it comes with two short links, one is between white live out and the yellow rad symbol and the other is again between white live out and the yellow tap symbol. What this does is one keep the boiler fired constantly for the heating and also keep a small tank of hot water hot at all times (preheat) , kind of like a store of hot water so you're not waiting too long at the tap.

If you take the link out for the tap symbol you only have hot water being heated as you turn the tap on. Similarly if you take the link out of the heating one it won't fire at all.


  • Hi @RaX,

    What is your Tado setup? I’m just trying to get my Greenstar 8000 connected using EMS, I have the live link in from L to LR for heating, and wiring the EMS is the same.

    I’ve tried the settings D17, D27 and D31 for both the smart thermostat and the Extension Kit, but not getting any response from the boiler?

  • Pretty Sure it was D17

    can you confirm your hot water works ?

    Did you set the jumper on the tado unit next to the boiler?

    Also worth telling tado support that you using Wireless Thermostat using EMS conenction and wireless thermostat in other room as they can set it remotely aslong as they can see the wireless bridge

  • Thanks @RaX, I will try again tomorrow with D17, I have fired off a support ticket to Tado, see what they can suggest. I don't think I tried the hot water while I was playing, but will give it a go tomorrow in the daylight.

    I did have the little jumper in position 2.

    I changed the settings myself via the Room Thermostat, changed the first setting to TS (previous install it was set to R01 as it controlled the central heating pump - TS is Temp Sensor, so instructs the Extension Kit when it wants heat). HC is set to 01, HW is X (no hot water cylinder), EK is ticked (Extension Kit) and then I tried D17, D27 and D31 from different searches, non seemed to do anything to the boiler 🤔

  • BruceR
    edited December 2020

    @JimboSquare Also just had a Greenstar 8000 Life fitted and trying to swap it over to EMS control. I sent a query to Tado yesterday but I haven't heard back yet. Tried everything I could to make it work, but no joy. I'll post on this thread if I get any progress, but it looks like until Tado support confirm a working config ID (D17, D31) then I have a suspicion that the 8000 will not talk to Tado. PS I have done about 6-7 hours work on this problem so far, but I might have missed something.

    If we get a 8000 working with Tado then I will write up the process as a new thread to save everyone else a bit of time/frustration.

  • If the timer is not setting the boiler on then check the EMS plug in the boiler make sure it’s pushed into slot properly
    Jumper should be on 1
    Also try swapping the wires around on ems plug or extension unit
  • Thank @RaX - I think I tried about 12 configurations, with the link from L to LR, D17, D27 and D31, without the link, then the same with 1 to - and again 1 to +, nothing seemed to fire up the boiler.... but I will try narrowing it down tomorrow.

    To speed it up I may try using the Smart Thermostat wired directly to the boiler.

    @BruceR - nice to know I’m not alone on this! I did read an article on the EMS-ESP that shows the EMS does work on the 8000, looks from what I was reading like it used a profile/comms settings from an earlier boiler setup within the project, hopefully it’s just a setting that’s not quite in the correct place.
    Hopefully we will hear back from Tado support soon!

    I did read a blog as well about the boiler being controlled using a different controller, they were having issues with the Honeywell controller / TRV’s trying to control the heating, but the timers (minimum burn, pump run on after burn etc.) on the boiler clashed with the short ‘call for heat’ from the TRVs and caused poor performance - I’m currently finding the boiler is ticking over most of the time during the day with different rads calling for small amounts of heat, but the on/off signal means the boiler enters a 5 min run on, by which time another TRV wants heat.....
  • @JimboSquare - I was using the Smart Thermostat wired directly to the boiler - I tried D17 and D31 with various combinations of L-LR open and shorted with a jumper wire. Also tried combinations with and without the jumper wire on the on/off thermostat input connector (the one next to the BUS connector). I think if Tado confirmed which ID worked it would narrow down the hunt somewhat. Let us know if you progress

  • @JimboSquare I just got this back from Tado:

    Thank you for contacting us,

    The Worcester 8000 Life Combi has a type of EMS bus that is not compatible with tado°,

    For any further questions, please do not hesitate to contact us.

    So bad news i'm afraid.

    I guess I need to get my Wemos D1 mini out and read up on EMS-ESP. I already have a Home Assistant hub running on a Raspberry PI.

  • That’s a shame I would sell it and buy the Worcester Bosch easy control and the wireless module so you can Have the thermostat else where
    You have a top of the range boiler and it’s not compatible with tado such a shame
  • Well that’s a bit rubbish, see how long it takes them to sort support for it......

    In the mean time, I was looking at the easy control, it mentions it can convert from opentherm to EMS for the 8000 - but not too sure on the direction.
    As in can accept opentherm from a third party controller and convert to EMS for the boiler, or does it convert EMS from WB controls to opentherm for 3rd party boilers.....

    I’ve a load of ESPs lying round so will start to tinker, would be good to have a opentherm to EMS so we don’t have to try and 2nd guess the Tado control algorithm - just do the conversion they should already be working on.....
  • Bosch easycontrol is for Worcester Bosch boilers use that
  • @RaX it looks like the EachControl can be used to speak to OpenTherm compatible boilers, not the other way round 😪

    Finally had the same response from Tado, at present they are unable to speak to the EMS Bus protocol the 8000 uses - but have offered to put some limits in place on the Extension Kit to limit the number of times it calls for heat - however I want to understand what that looks like - if its time limits, I'd only want to use that for small percentage calls for heat - larger % should ignore it (like a change in the schedule - if a room has been heated for a few hours and the limit is in place due to it modulating, and another room schedule changes and requests full heat - it should get it).

  • But your Worcester boiler supports EMS and the Bosch easy control should install easily using that interface and offer modulation using EMS
  • Apologies for the necro post - does it matter which way around the little orange EMS connector is wired up to the Tado? I am fitting my Greenstar 25i (internal wiring identical to the 30i) with a Tado wired smart thermostat. None of the low voltage connections seem to have an indicated polarity, either on the boiler stickers or in the manual. Does it not matter?

  • Hi all. Does anyone know how exactly the 8000 is wired to the extension kit. I had a cowboy install this boiler today. Changed from an older greenstar boiler and now the extension kit won’t work. I am using the tado thermostat wirelessly in another room.
  • Thanks Rax.

    Works like a charm.

    Spent hours shifting profiles from D1 to infinity...

    All it needed was the bridge you showed on the photo.

    Info for anyone else:

    My set is same as Rax

    • Worcester Greenstar 30i ERP
    • Tado smart thermostat
    • Tado Internet bridge V2
    • Tado extension kit
    • Tado Extension kit L and N wired to mains through fused spur which goes to boiler N & L in
    • On Worcester boiler L out bridged with L rad (radiator symbol)
    • Extension kit 36v/low voltage "-"and "+" connected to boiler "EMS"
    • Boiler how water bridge between "L out" and "L tap" removed (needed only for preheat)
    • Tado selected to D17 profile: button 3s, button 3s, button 3s, select "TS", ok, select "HC01", ok, select select "HWx", ok, select "EKv", ok, "SAVE", ok, wait for new settings to be downloaded
    • Modulation works as expected

    Cheers Rax

  • Hi Guys,

    New to all this, got the 30i and just installed the wireless controller, now seems that the boiler is fired up all the time.

    Wired as per the instruction pamphlet with L N Grey and Black going to the respective points.

    Been through the setup process and switched it show the LED show yellow, trouble is every time I do the test again to check, it goes back to green.

    Getting a bit frustrated with it all so any help would be very much appreciated.

  • I watched various video's and followed the Tado install instructions and I think I have now managed to get my 30i working, although do still have a minor question.

    I followed 2 paths: 1. Tado install instructions 2. Video by "LCW DIY", both very informative.

    Where I went wrong previously was following my sparkies information, which turned out to be totally incorrect.

    I started fresh at the boiler end and removed the two link wires, as per Tado Instructions & Video, and wired in as per attached pic.

    Controller tests fine, and I can confirm the HW Button does not work. My query is around the black wire and whether to leave it disconnected as per "LCW DIY" or connect as per Tado.

    Wiring is:

    Blue = Neutral Brown = Live Grey = LR (Rad Symbol) Black = LR (Tap Symbol)

    LCW DIY leaves the black wire off as the controller is not controlling hot water. What are other thoughts on this?

    When I first went into the connections, the Live & Neutral were on the 230v In side. I was previously using a Honeywell controller.

  • Hi,

    Can I add to this thread?

    I have the same Boiler but I have a V3 Smart Thermostat and no extension kit.

    I think this should connect direct to the GreenStar 30i Boiler via the EMS connections but when I set the ST as -





    With the Link L-LR the boiler then alternates between i 204 System waiting & i 202 Anti Rapid Cycle Mode.

    Also, the Smart Sensor is no longer a Zone Controller therefore no heating call.

    I change it back via the App digital by choosing Danfoss TP5 controller and the boiler operates as expected but I would rather be able to control the boiler by the EMS terminals as this allows the boiler to modulate, not just Off - 100%.

    If using the App, which EMS controller could I select to make this work correctly?

    Any help greatly appreciated.

  • @JimboSquare did you sack the Tado? I have a WB 8000 style which i just ordered a Tado wired stat for, if it wont run on EMS and modulation i might as well just cancel the order.