DIY to the MAX

Sometimes it looks like you have to do everything yourself…

While testing the ELV MAX system, I noticed that the Radiator Thermostats were off-schedule quite often. I don’t know why, but it’s a fact, and I have to deal with it.

Totally wrong! The weekly program I used in the past days was specifically created to monitor the accuracy of the Radiator Thermostats. Every 2 hours the temperature set-point was increased with 1°C;  starting with 10°C at midnight, 11°C at 02:00, 12°C at 04:00 and so forth. This way I had enough switch-points to see how these Radiator Thermostats would perform. Well, as you can see, the temperatures are totally wrong! Grr.

Why? I don’t know. But they are, for some odd reason. And the worst thing is, there’s nothing you can do to resolve this. Once the Radiator Thermostats have a wrong sense of time, you’re doomed and you’ll have to wait (for how long?) till the Cube resolves this for you. Hmm.

It seems that the Cube periodically retrieves the date & time from a time server on the Internet, so I wanted to know how often;  I took an old 10/100 Ethernet hub and connected the Cube and a laptop with Wireshark installed to this hub. Even after 36 hours, only 2 IGMP packets were seen. Even a power cycle didn’t make the Cube check to see what time it was. Too bad, I hoped I could find something that would trigger the Cube to check the date & time, but I’m lost. The Cube will probably check date & time once every few days or even a week, probably.

But can I live with Radiator Thermostats that are totally off schedule? No, of course not! So I had to write my own code to handle the weekly program and use that to control the Radiator Thermostats, until there’s another way to get the RT’s (Radiator Thermostats) working the way they should.

Autonomy is good for things like controlling the temperature in the house; it should be able to function all by itself, without the need for a Home Automation system to constantly dictate what the temperature should be – only when the residents want to overrule the default weekly program, Home Automation should kick in in my opinion. For now, that doesn’t seem like an option with the MAX system. It just doesn’t look completely finished yet? So much for the “Deutsche Gründlichkeit”.. I guess this is another examples of a product being pushed to market a bit too soon..

Nevertheless, 4 new Radiator Thermostats are coming this way; moving on! 🙂

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12 Responses to DIY to the MAX

  1. bernard says:

    Hi Robert,

    I don’t recognize this problem you describes here.

  2. ruszomir says:

    Hi again Robert,

    I’m planning to use a router with OpenWRT to catch Cube’s communications.
    But so far my Cube didn’t arrived so I have a question for you 🙂

    If you leave Cube alone, without connecting to it via web software, only with working radiators thought in – is there a communications occurring on port 80 of device? I would like to use router’s software to listen on that port, and catch packets for further analysing.

    Or is it just opposite: I have to send & receive commands using Max’s protocol.
    I’ve read that Cube accepts only one socket connection, so If I would like to use genuine software wouldn’t it interfere and cause lock-ups?

    Thanks in advance


  3. Hi Sławek,

    Only when you connect to the Cube (either with your own software or the MAX! software) there’s communication.

    To monitor the devices in your software, all you need to do is connect to port 80 and send the “l:” command periodically, which gives you the current status of the devices. I send this command every 2 minutes.

    Whenever I need the MAX! software (for example to teach in new devices, haven’t made that part yet) I just temporarily stop my own monitoring software and start the MAX! software. And when I’m finished and the MAX! software isn’t running anymore, I start my own software again. I do this because you can’t have multiple connections to the Cube.


  4. ruszomir says:

    Wow, that’s a fast reply 😉

    Thanks for sharing your knowledge 🙂

    I’m building a hardware solution (atmega32+Wizznet Ethernet module) to communicate with Cube. Than I could read status of valve pin position of radiators thus I would be able to switch on/off CH boiler when any of valve is open.

    Can’t wait to get my hands on Cube 😉


  5. Good luck and I’d like really like to hear from you when it’s working! 🙂

  6. ruszomir says:

    would you be so kind and send me an email with communications dump from Cube? Something more than I can find on forum.

    It’d let me work on it, while waiting for _my_ Cube 🙂


  7. Stuart says:

    Hi Guys,

    Don’t suppose anyone has looked at the internals of an ELV Max valve. Could it be re-purposed in the same way that the Honeywell HR20E can be re-programmed ?



  8. Stuart says:

    Wouldn’t it be great if it was an ATMega and RFM12B in the box. Somehow I don’t think we’d be that lucky.

    Looking forward to someone finding out.

  9. mario says:

    have you ever tried fhem instead of this cube think?

    • No, I haven’t. IIRC the time that FHEM and MAX! could work together was somewhere around late 2012?
      By then I had MAX! working reliable here, so there was no need for me to try it.

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