Support for the EMS2 bus - Bosch Condens

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Bosch / Junkers / Nefit boilers with the EMS2 bus have been on the market for many years now, have a large chunk of the European market share but Tado only supports relay operation for them.

I myself have a Condens 2300i boiler and while the relay mode works up to a point, the TPI algorithm operating the relay can't avoid over and undershooting desired temperatures. This particular boiler takes up to 30 minutes to reach a flow temperature of 55 C if many radiators are open, by which time the relay will usually have long since switched off only to start the cycle again once the water in the system has cooled to ambient temp. The room temperature doesn't rise enough and that makes Tado request more and more heat until the boiler is given enough time to reach the set flow temp and the room temp overshoots badly.

A third-party gateway is available that works with EMS2 and I'm thinking of trying to set up proper flow temperature modulation myself but without precise knowledge of how Tado would modulate if it could, it will probably be very tricky to set up.

Currently, it's hard to recommend the Tado system to anyone with an EMS2 boiler.

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  • Thx for posting. From Spain the same problem reported time ago, but no answer :(

    Could you please post info about third-party?

    ..... @ tado engineers, please listen to your end-users

    , Who trust you and make them happy again ASAP. You can !

  • Yes please develop support for EMS2. I stopped my subscription because of it, as the advanced features don't matter if no fine control can be achieved.

  • Same problem here, please Support ems2
  • +1 What is this third-party gateway?
  • scaraby100
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    +1 Need this ASAP, please implement
  • fgmarin22
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    I bought a Bosch 4300iw boiler a few days ago in Spain, and also the Tado starter kit (this from Amazon). I believed it would work in modulation mode, because I read it in the document "Guía de Compatibilidad para Termostato Inteligente V3+" from Tado. For my surprise, after hours trying to find out, I saw this thread, and got very disapointed. Please, develop something to make it work!

  • fgmarin22
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    This is the document from Tado where it says that Bosch is compatible both in relé and modulating modes.

  • pmatthew
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    I also have the same boiler (Bosch Condens 2300) and the same problem... I found this adapter, could this be working with Tado?
    https://www.plugwise.com/product/nefit-opentherm-ems-converter/
  • scaraby100
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    I don’t think we will see this coming up in the current products lineup.
    EMS 2 protocol logics could be too complex for current smart Thermostat computational capability.
    I could be wrong, but I think if this implementation was possible, they would have already made it.