Support for the EMS2 bus - Bosch Condens

dmaly

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.

Tambi

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 !

Gert89

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.

Kevin_Cookie

Same problem here, please Support ems2

jeffmcfly

+1 What is this third-party gateway?

scaraby100

+1 Need this ASAP, please implement

fgmarin22

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

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

pmatthew

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

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.

FastLane

Seems as if Tado X doesn't have EMS2 either :-(

policywonk

What about the Worcester Bosch Easycontrol adaptor? I understand it can handle EMS2 and interface it to Opentherm. Had anybody tried that with the intention of connecting to a Tado system?

SteOH

That adapter is effectively for the reverse.

It's so you can use the Bosch Easy Control stat with an Opentherm boiler with modulation.

The Nefit is for EMS "1" and it doesn't seem to be easy to establish what version of EMS is on a specific model.

SteOH

I would hope with the existence of a device such as this:

https://github.com/emsesp/EMS-ESP32

Or the equivalent for Vaillant:

https://github.com/danielkucera/esp-arduino-ebus

That Tado might consider coming back to this. The EMS-ESP32 appears to have no issues between EMS, EMS2, EMS+ etc. etc.

But I don't necessarily hold Tado responsible as the issue here seems to be a lack of regulation about interoperability.

willouf

i applied to this request !

I have ELM LEBLANC iCondens Egalis Ballon and TADO is still not compatible with it

policywonk

@SteOH. @willouf, @pmatthew, @fgmarin22. A couple of months ago, was having a conversation with one of the senior geeks at Tado - the volunteer moderators here occassionally the option to ask questions a few times a year. That gent was open, thoughtful, understood me immediately when I stated that whilst EMS1 hurdles can mostly be addressed, EMS2 hurdles were proving to be a pain. He responded in this way (my memory, not his words):

• Whilst EMS1 was reverse engineered and was logical, the introduction of EMS2 took it to a new level - with lots of interface matrices needing to be identified, none published, some being product specific. Heat pumps added to the complexity.
• The work involved to decipher unpublished protocols, especially when manufacurers would release mods a few times a year, was proving to be excessive. Much of this could be caused by the manufacturers having enough trouble bringing products to market which had past beta testing and could create a competitive edge. They didnt have time and did not want the cost of involving or explaining themseles to others when there was no commercial benefit to themselves.

That explanation is echoed in my experience on this forum.

• Most modern boilers have the capacity to control their energy output and one needs to engage that protocol.
• Yet some companies - including Bosch, Vaillant, etc - seem to espouse an attitude, likely a policy which, in short is: dont use third party devices, we dont believe it will work anyway. They wont offer advice directly to end users to overcome even the simplest steps which require their ribbons between PCB points needing to be moved- and they've clearly formed a view that to publish their protocols transparently and respond to their clients on how to engage those protocols involves a cost which they dont believe is justified.
• The companies which actively work with Opentherm are different, most repond to questions quickly, understand why, and happily provide referrals to published documents which then helped me to understand increasingly how to cohabit with Opentherm.
• It has nothing to do with quality or efficiency, reliability or cost-effectiveness. If the protocol is handled badly it causes the boiler to cycle and the burners to wear out quickly. End user long term reputation doesnt seem to allow for this.

Thats my interpretation - and it may reflect individuals staff attitudes, not company policy. Whilst I was genuinely dissapointed that Tado had decided not to support the other bus protocols with the X series, I could finally see why Tado elected to focus on Opentherm. It restored respect.

Sorry been away, busy at work. After reflecting on this thread again, wondering what was going on in the Netherlands- as they did something pivotal, mandating Opentherm compatibility- I stumbled upon this:

Worcester Bosch EasyControl | Some good news Netfit Bosch are releasing a EMS2 to Opentherm converter that allows communication between EMS1/EMS2 protocol to OpenTherm-compatible ... | Facebook - and that led to this: 6720817889.pdf. There is a Nefit part, 7736702317, which handles EMS1 and EMS2 two way conversion to Opentherm, now being advertised on Dutch websites.

Any use to you? Do let us know. Others will benefit from what you do.

Montage

I bought a similar Nefit Bosch device in 2019. Slightly different part #, but looks the same. Price has gone up a bit. Have passed it on to a friend to use with his WB boiler.

vmguru

EMS2 to Opentherm now available

https://www.nefit-bosch.nl/professioneel/meer-over-de-ems1-2-ot-converter

tyor33

I will be needing one of these EMS 2 converters as my Worcester boiler only has an EBUS port. With one of these converters and either the EU Tado or Tado X. Should that work to control the boiler?

Montage

As long as you are happy with the Tado OpenTherm implementation.

vmguru

@tyor33 Yes the Tado EU version, Tado X, Nest, other Opentherm thermostats should work with modulation. The EMS1/2-OT converter (7736702317) is available in parts of Europe.