New combi boiler, smart wired thermostat permanently demanding heating

Hi all,

Have just changed out our old system boiler for a new combi boiler. previously was running the system off the wired smart thermostat. we've tried to connect that to the new combi boiler but the boiler is constantly being given a demand for heating, even though all of the rads are turned off on the tado app.

Is there a wiring diagram or some changes that might need making to make sure the signal from the wired thermostat is only on when the demand is there?

Many thanks,

Patrick

Answers

  • Have you contacted tado support for new installation instructions for your new boiler.
  • I'm trying to contact them but they're not exactly quick off the mark are they.

    If there's any advice on how to approach tado support for that information that would be great. Cos all I can see is bots and FAQs and no human beings to talk to.

  • Montage
    Montage ✭✭✭

    The wired stat (like any stat), will only call for heat when there is demand. There isn't a setting for that.

    You'd probably get a quicker resolution on here. You'll need to provide info regarding the set up.

    I'd start the speculation with disconnecting the stat.

  • Didn't get chance to do much with this over the weekend, but some additional thoughts/comments! Thanks for the responses so far.

    We used to have the wired thermostat and an extension kit with the old system boiler. When we changed it for a combi boiler, the extension kit went.

    1. Do we need to change anything in the Tado set up to let the system know that it is now part of a combi boiler system? We don't have a zone controller set up for the home, could that be causing a problem?
    2. When the smart thermostat is on the wall, there is a permanent live going back to the boiler, constantly demanding heat from the radiators, so the combi is always firing. When i unclip the smart thermometer off the wall, that demand goes and the boiler shuts down. So, either there is something in the wiring when that circuit is completed by the thermometer, or something in the software that is sending a signal away from the thermometer permanently. (could this be because of anytihng to do with point 1?)
    3. Heating engineer doesn't want to change any wiring connections inside the boiler itself, in case it blows the board or invalidates the warranty. Can't argue with this until we've resolved other options. I can't imagine that of all the hundreds of new boilers being installed up and down the country every day that we would need to change the default connections to connect the Tado.
    4. In order to resolve point 1, my next step is to try and remove the smart thermostat from my tado app, and then reinstall it as a new device, in the hope that it will take me through a full set up for the house and allow me to instruct the system that it is a combi boiler now. But I'm worried that if i do that I won't be able to reinstall it and the house will be left without heat whilst we try figure it out.

    Any thoughts please?

  • Montage
    Montage ✭✭✭

    Sounds like you've proved the Tado stat is causing the call for heat. This could still be a wiring problem.

    Follow either route to reconfigure Tado for the new boiler https://support.tado.com/en/articles/3657753-i-have-a-new-boiler-how-can-i-connect-my-tado-devices-to-it

    The Tado will know how to behave. I suspect you'll then need to check/sort wiring, TBH.

  • Hi @Paddy1983

    Yes, if you had an extension kit then it was almost certainly controlling the heating via its internal relays. The relay on the smart thermostat would have been permanently closed which is almost certainly why you're now seeing the heating running constantly

    I believe you will need to change the zone controller for the smart thermostat to "No Zone Controller". In the app, go to settings and the room that has the smart thermostat. You should have a zone controller setting at the bottom of the screen. It will likely be set to your extension kit at the moment. Change that to None or No zone controller.

    Check the zone contoller setting for your rads too. They will need to be changed from the extension kit to the smart thermostat

    Once done, you should also be able to remove the Extension kit from the home

    No wiring changes should be needed

    HTH