Not all thermostats start boiler

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We have TADO system is based on Valliant Combi boiler, Wireless Receiver, Internet bridge, one wireless thermostat and 12 TADO smart thermostats and 3 basic model TADO thermostats in 14 rooms. All are connected, no errors, display when changed from the app. There are no separate zone controls.

The problem is that 5 rooms out of the 14 are not calling for heat and starting the boiler. The others are fine.

The app shows 3 heating bars for the not working thermostats but Receiver does not respond.

Problem seems to have started when I added the three basic tado thermostats. They connected straight away, but I cannot be sure that they ever started the heating, they connected and I thought they were fully functional. These are not the only ones that don't work now; two of the smart ones don't either.

My understanding was that the system can handle 25 units and that the types of thermostats can be mixed.

Any ideas what is wrong please?

Comments

  • johnnyp78
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    As far as I know there’s a ten room limit per zone controller. Any rooms over that number can’t call for heat.
  • mindstorm
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    I've got 12 TRV's and have had to set two to be dumb rather than linked to the zone controller. If you check Energy IQ you can see which TRV's call for the least heat, I've set those to be the dumb ones. For me it's a bathroom and a utility room.

    There is a couple of rooms with two SRT's in which I could group but I haven't so far as they are two 24' long rooms with a big door at one end of each so only one area gets solar gain.

  • CBen
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    Thanks for the answer.

    Thats what I suspected. Its frustrating as the "25 units capability" message is prevalent in the documentation.

    Ideas for getting the system to work for me?

    My first thought is to use the wireless thermostat as a timer. Or could I use another wireless receiver wired in parallel with the existing one. Having already spent more than 800 pds I am reluctant to spend more.

    For the moment, I will swap one of the thermostats in rooms with two back to manual TVRs. Not great though.

  • johnnyp78
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    You could probably parallel wire a smart thermostat in as a second zone controller (Tado officially only supports one wireless receiver per system). That might be the easiest solution.
  • mindstorm
    mindstorm ✭✭
    edited October 2023
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    You can check which ones are attached to a zone controller in the Settings/rooms & devices menu. Click on the room (not the SRT assigned) and scroll to the bottom. It will either have the zone controller or not assigned. Make sure you have 10 assigned out of your system.

  • CBen
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    Thanks for your input. I see that under the room settings the room can either be with one zone controller or independent. Does independent mean that they can call for heat or not? That would neatly overcome the 10 room limit.
  • swedishhh
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    I wonder if this is my problem too. I have 11 rooms, and about 16 TRVs, and some mornings the heating doesn't come on until i press the test button on the receiver. That seems to choose it into action.

    I'd have the same question: can independent trvs call for heat, and what are the downsides in doing this?
  • johnnyp78
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    Making a room independent of a zone controller means it won’t call for heat.
  • Glasofruix
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    Yup, and i make use of that, because there's actually no need for every room to be able to call for heat.

    I have about 13 radiators and 8 TRVs (no need for connected trvs in the hallway and the bathrooms for example), i made it so only two can call for heat. One is in the living room since it's the room that cools down the quickest in my house, the other one is in the bedroom with a wireless sensor and i might allow the one in the office when it gets colder. We also redid the insulation of the whole house earlier this year.

    So basically, the living room (which is downstairs) is the room that calls for heat the most (maybe every two hours or so), the TRVs in other rooms keep the radiators closed as long as the set temp is kept, it heats up the other radiators with dumb trvs and just that is enough to keep the whole house nice and warm at the moment. If another room needs heat, the valve opens the radiator and waits for heat from the living room which will turn on the boiler eventually. The temp loss in those rooms is about 0.2 - 0.5 C° in that interval. So far this prevented the boiler from running continuously and since tado is modulating the water temp rarely goes above 40°. The gas consumption is about 1m3 a day or less (we'll see when the outside temps drop later this year).

  • CBen
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    Thanks for your input. It seems to work for you. As you say, it could be that as temperatures drop, things may change.

    We have a number of rooms that tend only to be used when we have visitors at weekends and I do have an aversion to heating rooms that are unused. Ours is a combi-boiler so the water temperature frequently exceeds 40°.

    With a lot of intervention, our October gas usage was 700 kWhr about 2m3/day. Based on the previous months without heating, probably, about one third was water heating.

    I am trying to get to the bottom of the TADO information about device numbers and zone controllers. It all seems very vague even in the professional area. For example, even if the system has two physical zones I haven't found how the second valve is controlled if, as been pointed out, it will only cope with one wireless receiver.

  • johnnyp78
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    The second valve would be controlled with a smart thermostat. Really the only purpose of a wireless receiver is if you’re in the uk/ireland and you want tado to control your hot water cylinder heating or if you’re in Europe and you want a mains rather than battery powered device.
  • CBen
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    Thanks johnnyp78. I presume that the "smart thermostat" referred to is the Add~on Wired Smart Thermostat? This would have the call for heat function?

    Returning to my real issue - controlling more than 10 rooms on one heating circuit. Would I be able to use a wired thermostat as zone controller 2 for the extra rooms, even if not connected to as a zone control valve?

    Ideas, please?

    Not directly connected with this, I have another issue - our builder supplied an independent Hetta underfloor heating system based on a Wi-Fi connected thermostat/programmer that does not do what is required of it due to changes to the Smart Life App that seem to have made it the Hetta system incompatible.

    It would be great if Zone 2 could also incorporate that under-floor heating. Does anyone control a Hetta system, if so how?

    Many thanks.

  • johnnyp78
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    Can’t answer much of that but I would think that for tado to recognise a device as a zone controller it would need to be wired to something. Maybe Tado support could override this though.
  • CBen
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    So far Tado support has not been very helpful, which is why your input is valuable. Thanks
  • revdickvenn
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    I parallel-wired a second smart wired thermostat in March 2023 and then all my valves could call for heat and turn the boiler on. The second one was set up (by Tado) as a second zone controller (zone 2). This all worked nicely until about 6 weeks ago, and now it won't work properly. Not sure what's going on, am communicating with Tado about it.

    Dick

  • CBen
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    Good luck with Tado. Be interested in their response.
  • revdickvenn
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    They reply but don't seem to understand what I'm saying most of the time and I have to repeat it over and over. Still not fixed and am wondering if either my second smart thermostat is broken or Tado have altered what goes on at their servers end.

    I can hear the thermostat click but it doesn't seem to communicate with the extension kit and turn the boiler on.

  • CBen
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    You may be up against the Tado policy of just one switching circuit. They seem not to countenance any other way. It's a pity, because it makes their system much less attractive in a number of locations.
  • revdickvenn
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    Weird thing is, they cooperated and let me have a second zone, using the second wired smart thermostat (wired in parallel) to control the second zone which then turned the boiler on when smart valves hooked to that zone asked.

    Then it stopped working.

    But as of today, it seems to be working again!

  • revdickvenn
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    and of course, you don't know this until you're heavily invested....