Vaillant ecotec 831 plus install

edited February 5 in Technical Questions

I have to admit im no boiler engineer but I have been following the threads and decided to purchase the tado starter kit v3+ wireless. 

Set up i thought would be quiet straight forward until it came to actually spring it out.

I assumed if I followed pages 16 to 19 (of the attached) to configure the smart thermostat (using D07 Standard Vaillant eBus )

Then connecting the vaillant BUS + and - (boiler side) to the + and - on the MAX 36V DC side of extension kit

I assumed there was no need for L and N on extension kit as it gets its power from eBus, jumper link can be set to ether, it doesn't matter which way its round.

However when following the app set up guide it stated something different. It has 3 different device models,( ecotec plus 800 plus series (combi)), for my Vaillant ecotec 831 plus.

I claims for 1 need another power cable and the other 2 look similar.

So now I'm lost how to wire it up. Do I follow the app or what is my belief above.


  • I presume this is a combi.

    Connecting the ebus is straightforward, as you say. These seem to also require the loop in place (switched live) to create a permanent call for demand. Then the boiler responds to the ebus.

  • I have no time switch on the boiler itself at all. The boiler needs to be set to permanently 'on' in order for Tado to control it.

  • Hi

    So looking at the board do I just connect direct to the ebus + and -

  • scgf
    edited February 6

    That's what I did. Sounds like you've correctly configured the thermostat for D07 (Vaillant eBUS). Just the two wires from the + and - eBUS connections on the boiler to the + and - on the right side of the extension back plate. The extension box is powered through these wires too.

  • Thanks. I'll see how I get on and any problems ill have to come back

  • I'll give it a try and tell you how I get along

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