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EMS Bus wiring

Looking for wiring connections and setup for Worcester Greenstar CDi Classic to enable control using the EMS Bus (If possible) I have it connected using contacts at the moment.

Thanks in anticipation

Phil Holmes


  • Hi Phil,

    I can only confirm EMS is supported by Tado (I am using it with my Buderus heater). Did you try to use their step by step install guide?



  • edited December 2019

    Hi Andrei

    Thanks for the response. It didn’t give me the option during the installation process. I found a document related to wiring a Vailent to eBus and a Worcester to WT-Bus but not a Worcester Greenstar CDi Classic to eBus. It may be the same but on my boiler I only have some contact marked up EMS BUS.



  • XeonJaXeonJa
    edited February 6
    I would also like to know this ems setup, I’m assuming it’s a setting within the thermostat. I know the the ht-bus is d16 or d17 on the thermostat and does this need a Worcester adapter converter thing
  • has anyone got EMS working with the worcester boiler

    i have just wired my extension kit up to the EMS bus, but on the tado docs it only mentions the HT-Bus with BBv on it , i tried D17 from there but that doenst work, the tado is powered up from the EMS bus ok, just not communicating properly which i assume is becuase of the D value in the thermostat setup

    Tado do you have some up to date instructions to wire and configure for EMS bus on worcester boilers.

  • Anyone scratching their head about why the worcester bb connection doesn't seem to work like I was, it does work! But you have to wire lr and ls together on the boiler, it's in the worcester wave setup instructions (wave setup seems v similar to tado, tado needs d17 to work). Good luck!
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