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Thread: How to read the Vaillant eBus

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  1. #1
    Automated Home Jr Member
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    Default How to read the Vaillant eBus

    I have a Vaillant EcoTec Plus boiler. I don't want to control it but I'd like to be able to read the values of flow and return temperature so I can plot them on a graph.

    I've searched the internet and it appears that this can be done with an Arduino, but most of the posts on the subject are in German which I don't speak.

    Does anyone here have any relevant experience please?

    Mike

  2. #2
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    Ebus isn't an open standard, but there is a linux daemon called ebusd that can read the data, Vaillant's ebus implementation is constantly changing with their products and isn't widely known.

    However, there is a solution but you'll need 2 devices:

    Vaillant make a device called the VR33, which isn't available in the UK (and will invalidate your warranty if they found out), but can be purchased from Holland via https://wifithermostaten.nl/vaillant...dule-vr33.html. This will bridge ebus to OpenTherm.

    With OpenTherm, you can then use an OpenTherm Gateway (aka OTGW: http://otgw.tclcode.com/), which is a not very useful serial interface, but thankfully Cyril has made a module for an OrangePi which means you can have it in a far more accessible computer/wifi interface: https://www.domoticaforum.eu/viewtopic.php?t=11816

  3. #3
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    Thank you, that's very helpful.

    There are some very clever people out there

    My boiler is 9 years old so no worries about the warranty ...

  4. #4
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    After some further research it appears that Vaillant used to offer their own solution:

    https://www.mytub.co.uk/vaillant-vrd...product-107928

    The hardware is no longer available but the software can be downloaded from some (non-UK) Vaillant web sites.

    I also found this commercial eBus to USB adapter:

    https://www.esera.de/produkte/ebus/1...re-hub-platine

    So many options, my head is hurting ...

  5. #5
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    I'd be a bit cautious of using a VR33. I have one and use it to give Evohome OpenTherm control of my boiler. I also monitor eBus (using ebusd) and collect a number of key parameters every 30 seconds. I see some very strange behaviour on the boiler which I'm struggling to believe is commanded by OpenTherm. My current working theory is that the VR33 is doing something weird. Perhaps it's not truly compatible with the UK boiler firmware, hence why it's not officially sold here?

    Building an eBus adaptor is not very hard. This is the one I built: https://wiki.fhem.de/wiki/EBUS

    You'll find a reasonable list on the ebusd wiki: https://github.com/john30/ebusd/wiki/6.-Hardware

    The one I built is the third link (the Prof. Hanning one). Note that the current recommended one seems easier to build.

    The ebusd software is a little bit more interesting. If you're lucky, your boiler will already be supported. If not, you'll need to do some experimenting. Plus, when I set mine all up 18 months ago, the VR33 wasn't directly supported, so I had to figure a bunch of stuff out for myself. It's so picky, in fact, that I've left mine alone since I set it up. It works, I get my stats every 30 seconds, and I don't want to run the risk of breaking it.
    Last edited by dty; 16th December 2018 at 10:27 PM.

  6. #6
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    Quote Originally Posted by dty View Post
    I also monitor eBus (using `ebusd`) and collect a number of key parameters every 30 seconds.
    Thanks for the advice. This is exactly what I want to do. Are you using a Raspberry Pi with your adapter?

    Also, what connector is needed for eBus on the boiler?

    Mike

  7. #7
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    I can confirm that the Arduino circuit mentioned above works absolutely fine. But is READ only. So you will get the ebus data. You will still need software like ebusd or similar to actually make sense of that ebus data byte stream. This is where the RPI comes in. I have a NAS sitting near my boiler, so my software runs on the NAS itself. The software turns the byte stream into individual messages, that you then have to parse for the values you are interested in.

  8. #8
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    Also bear in mind that you can only read messages that happen to be flying around on the bus. If you're after something that's not actively being talked about by one of the components on the bus then you'll need to build a proper adaptor to allow you to write to the bus to request the data you're after.

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