Remeha Calenta connected

The TTL-RS232 converter

The TTL-RS232 converter (click for more detail)

After nearly a full afternoon of soldering, testing, debugging I finished the board shown above. This is not my cup of tea, that’s for sure… 🙁

I forgot to add 1 wire (the red one to the right of the MAX3232) and the whole thing didn’t work… so I checked if all the wires were there, and I still thought they all were; next I checked if the cable coming from the Remeha was 100% OK – it still was; I re-checked all connections; and finally, after 2 hours, I found that capacitor with one leg connected to nothing. That can’t be right.. after I fixed this everything worked as well as on the breadboard. Pfff.. Next time when I solder something similar, I’ll make a hard-copy of the schematic and I’ll mark the components and wires I finished soldering on that hard-copy, so I won’t make this mistake ever again! After connecting the female DB9 to the RFXCOM RS232 module, I was good to go.

This was the hardest part. From this point everything went very smooth:

  • I changed the Calenta Interface settings from using a Serial to using a TCP Connection, as in:


  • I built my Domotica Delphi project (nothing more than Shift-F9 inside the Delphi IDE);
  • I set the Remeha Interface “AutoRun” property to True in the database, which means it will automatically start whenever my Domotica system restarts;
  • Created a backup of the executable I used until now (v145, with v1 being 5 years old right now);
  • Copied the newly built executable to my Domotica VM;
  • And restarted it…

Ooww yeah, this is it 🙂

A long-cherished wish has been realized; unexpected, relatively simple and cheap!

Calenta charts

Calenta charts


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9 Responses to Remeha Calenta connected

  1. eRJee says:

    Does is also already works via OpenTherm of through the Remeha protocol ?

  2. djdive says:

    And there you have connect this interface on the remeha?
    On the rj11?

  3. PietG says:

    I am not able to get the rihgt software. On the Remeha download site the downloading of the new software for the Avanta and the Calenta is blocked. Only the archive with older software is functional. But with the older software i get an error: “Could not parse configuration file”. The interface and cable is working: you can check the handshaking.
    Can someone help me at the correct software??

  4. Ariën says:

    Hi PietG,
    read your comment. I’ve the software on my laptop, but as curious as i am, i tried to redownload it from remeha. And guess what, it still works…
    On the remeha professional site it is…
    Good luck

  5. PietG says:

    Yes, i was able to download the new software (4.1.1) but guess what: it crashed immediatelly. The error is : ” An unhandled exception (‘System.Configuration.ConfigurationException’) occured in Recom.exe [4356].
    This happens always at startup, even without an interface connected. The old version (3.0.4) runs alright but misses the Calenta .txt file.
    To my surprise this file is also not included in the new software config directory with .xml files.
    What do i wrong????

    • Piet,

      Here you can see the model, bottom right for my Calenta, so it’s not the same name as on the invoice 🙂

      I’ve not had any problems with the software… Install & Run… so can’t help you there.

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