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Zone valve


I'm having trouble connecting my zone valves to my thermostat.

After having made a whole series of tests, it would seem that the thermostat remains blocked as in red on the image:

Is there a parameter that I have not entered correctly in the thermostat to control this?

I imagine that there must be a relay which switches from NO to NC depending on the heating demand.

For my part, I tested connecting to NO, my valves open and on NC, nothing happens.

There is therefore no current on the NC but permanently on the NO.

It's very annoying because for the moment, my floor heating is running non-stop ...

Anyone have a solution?

Thank you in advance !

Best Answers

  • TeddD88TeddD88
    Answer ✓
    Ho good idea I didn't think about the offset !

    Thank you @Joey you're the best !


  • I juste made another test with a simple bulb and if I connect it on NC-COM it stay off even if the temperature is lower than requested.

    If I connect it on NO-COM, it stay on.

    It confirm me that I probably miss somthing on the thermostat as I can test both the valves (with an power switch) and the thermostat (with the bulb).

  • samdsamd ✭✭✭

    @TeddD88 Not really much help I'm afraid as my wiring is the same as yours but does not carry 230v. Have you tried the chat line on tado.com

    Stupid question but have you put the batteries in your thermostat!!

  • Hi @samd,

    Indeed, there are batteries in my thermostat.

    He's working fine but except for that.

    But the way, I have it til 1 month now so I guess the batteries in not in charge and if was, the relay should been on NC and not on NO.

    But what do you mean with "but does not carry 230v" ?

    Do you have motorised valve with less power ?

  • samdsamd ✭✭✭
    edited January 14

    @TeddD88 I probably clouded the issue by mentioning 230v. My thermostat is only controlling the boiler so it just makes or breaks the circuit and carries no power. I mentioned it because the make/break (i.e. On or Off) works with the two wires on NO and comm with no problem.

  • Alright.

    By the way, I make another test by changing the parameters in the thermostat :

    R01/HC01/Ek V/HW X/D07

    Like this, the valves open when I turn the temperature up but unfortunatly it doesn't close when I put it down.

    I hear the noise of the relay so it partialy work.

    Even, the valves close if I restart the thermostat (so the relay put it from NO to NC).

    It's another proof that the problem is only software and not hardware !

  • @samd how does you your thermostat being configure ?
  • samdsamd ✭✭✭

    @TeddD88 I don't have any parameters to change - sorry can't help there.

  • JoeyJoey | Moderator

    Hello TeddD88.

    I have replied to your Support Request, I apologize in advance for my terrible French translation,

    Thank again to @samd for pitching in! ;)

    Just to give an insight as to how this was resolved. As @TeddD88 already had an existing/established tado° set up and a change needed to be made to the Smart Thermostat (from wireless to wired) the support team was needed to make a change.

    Kind regards,


  • Thank Joey, it work !

    I send you an email but it will be easier in english 😀. By the way, you're french is just fine!

    There is only a small delay after I decrease the temperature and the relay react. I suppose that it is normal ?

    Another question, is it possible to add my old thermostat (Vaillant Calormatic VRC 470) to let him drive the boiler and let it modulate ? I think I've seen it possible on the professional instructions.
  • Hello Joey,

    Thanks for the explanation and the informations !

    Have a good evening !
  • Hey @Joey ,

    For the proper functioning of m'y valves, it would be good if they open and close at least once a month.

    This is not a problem in autumn / winter but in spring / summer, the heating is switched off and therefore the valves will nor open nor close.

    Is there a way to manually control (or via an application, ...) the relay of the Tado thermostat so that it switches on and off?
  • JoeyJoey | Moderator

    Hello TeddD88,

    Yes, you can manually control the relay from your app and manually from the Smart Thermostat. You could simply turn the heat up for a few minutes and then off again.

    Even if the temperature in the room is over 25°, you could set an "Offset" and trick the Thermostat into thinking it is much colder than it really is. Then turn up the heat for a few minutes, then off again, then remove the offset again.

    Check option 2 in this article: https://support.tado.com/en/articles/3405606-i-think-that-the-real-inside-temperature-is-higher-lower-than-what-tado-is-showing-what-can-i-do

    Kind regards,


  • samdsamd ✭✭✭

    @TeddD88 Or you could allocate allocate one of your sets of 3 'schedule days' for a summer schedule which turns everything to off but turns the valve on for a couple of minutes every day or whatever period you wish.

  • @samd how could I do that ? Is it possible trough the Tado's app ?

    I also thought to install a connected switch wich could cut the link between the valves and the thermostat and open the valves with a programmation.
  • Or this : https://sonoff.tech/product/wifi-diy-smart-switches/4ch-r2-pro-r2
  • samdsamd ✭✭✭

    @TeddD88 On the app select smart schedule and half way down the page it says schedule days. You are the schedule shown. Select it and it gives you 3 options for days to schedule e.g. mon-sun, mon-fri, sat and Sun etc

  • Ho found !

    Thanks @samd

    I'll let you know what's work better in the past months.
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