Smart TRV not working as expected

I’m hoping someone can point me in the right direction and explain why 2 out of my 6 Smart TRVs are not behaving as I have programmed them to.

The setup I have is: Wired Thermostat in the Living Room (had this years and decided to invest in the TRVs). On Tuesday, fitted the new TRVs, set up and connected easily and call for heat when scheduled.

The issue I have is I have two TRVs scheduled to be turned off first thing in the morning (the bathroom and playroom as they’re set to come on at a later time), but they show the same temperature as the living room and hall even though they’re switched off.

The radiators are cold, room certainly isn’t the temperature it’s displaying on the app. Any ideas on what I can do to rectify this? Of course, the problem is when it is scheduled to call for heat, it isn’t because it’s reading a temperature that isn’t correct and the radiator stays cold.

I do have screen prints that show exactly what’s happening, just a shame I can’t attach them.


  • cbd20
    cbd20 ✭✭✭

    @MsWilko if from your phone you "Request Desktop Site" this will then enable the buttons to upload images in the comment box as below:

    To do this in Chrome on Android click the 3 dots top right then tick the box saying "Desktop Site" near the bottom. For iPhone there's a similar setting though I don't know off hand how to do it.

  • As you can see, the radiator in the Playroom is set to OFF (It’s only scheduled to come on between 15:30 to 20:00 at 19°c. The graph shows the room warmed on the same trajectory as the Living Room schedule, but when I checked, the radiator was cold.

  • This is the Living Room schedule for comparison. The Playroom backs onto the living room, but it is a separate room and doors are shut.

  • cbd20
    cbd20 ✭✭✭

    @MsWilko so this effect to me looks like the valve in the playroom isn't closing properly and is allowing a flow of hot water through even if it's just a tiny amount, as the gradients align pretty well with when the Living Room is requesting heat.

    Now I know you said the playroom radiator was cold when you checked it, but it's probably still worth confirming that.

    What I would do is when you get a moment is turn the heating right up in the Living Room to ensure the boiler fires up. Then stand in the playroom and feel the radiator and the incoming/ outgoing pipework to that radiator to see if they start to warm up. If they do then the valve isn't closing fully and then you'll need to check the valve pin movement and recalibrate the tado thermostat. There's other things to try too if the radiator valve does seem to be allowing a flow of water through.

  • MsWilko
    edited January 2023
    @cbd20 Thank you for your help. I’ll try what you’ve suggested and report back how I get on.
  • This happened in one of my rooms too. As far as I could tell it was the pipe below the Tado trv filling with hot water and causing it to think the room temperature was heating up, even when the radiator was stone cold. In the end I just got a wireless temp sensor in the Black Friday sale, which solved the problem, at a cost
  • @cbd20 I waited until the living room scheduled to come on this evening and checked the playroom. The radiator didn’t heat up, but the pipe leading to the TRV did. I’m assuming the TRV is reading the temperature from the hot water in the pipe?

    If so and it’s similar to what @johnnyp78 experienced, do I need to purchase a Wireless Thermostat Sensor for the room, or is there anything else I can try?
  • Just a quick thought, was that radiator working correctly with the original TRV? If the pin sticks down or is stuck down or jamming, then the radiator will not get hot in any case. Just a thought

  • @ken_s yes, the radiator is working thankfully (before and after). I turned the heating up when I first installed them earlier in the week and did the same for 10mins in each room to check that I’d set them up correctly.
  • WillYZF
    edited January 2023

    I was thinking of getting some Tado Smart TRV's to supplement my Tado system but am now questioning whether I will have similar problems versus non smart TRV's

    I really don't want the extra expense of wireless temperature sensors either.

  • @WillYZF to be fair, it’s only 2 out of the 7 that I’m trying to sort out. I still need to check the pins to make sure they’re working properly but overall it’s fantastic. Finally the bedrooms can be heated properly as it was relying on the wired thermostat in the living room that is located behind the TV, so with the heat that was throwing off, no rooms heated properly unless it was first thing in the morning when the heating kicked in.
  • cbd20
    cbd20 ✭✭✭

    @MsWilko it does seem like what you're seeing is potentially as @johnnyP78 has suggested with the thermostat detecting the pipework heating, albeit that doesn't align with my experiences.

    In my house if a tado valve is closed the pipe to the radiator doesn't heat up, but that could very much be house and heating system specific. Theoretically if the valve is completely closed there's no water flow to that radiator, so you're relying more or less purely on heat transmission through the "static" water in the pipe to raise the temperature. I guess if the run of pipe is short enough that would produce a noticeable increase in temperature.

    One final experiment that might be worth trying is if you have an old manual TRV still, temporarily refit that to the playroom radiator. Turn it right down to frost protection/ off, so the valve is essentially closed. Then turn the lounge heating right up again and see if the pipe still gets hot then. If it does, then you're experiencing something similar to @johnnyp78. If it doesn't heat up, then it suggests that the tado valve is letting a tiny flow through.

  • @cbd20 oh that’s a great idea! I’ve kept the TRVs I swapped out as there’s always a possibility of a house move so would be wanting to take the kit with me.

    I’ll keep you posted 👍🏼
  • How hot are other rads? After installing tado and full configuration I hardly ever feel radiator heating at the blast be really hot but still get enough heat.
    Would you be able to post few more pics of graph from alend of the day against your schedule?
    That might let us see how it behave with heat calls to boiler.
  • If you've had to use adapter pins to fit the Tado TRVs then could choosing the wrong size one cause the valve to stay slightly open? Or is the TRV smart enough to know you've used the wrong length pin?

  • @cbd20 I think you cracked the case! I took off the “playroom” TRV and followed instructions I found online to unstick the valve pin. Recalibrated the TRV and refitted. Seeing as I was doing this for one, I also completed this little exercise on all TRVs. I set the heating in the living room to 20°c for 60mins and took screenshots an hour apart. From what I can see, this has fixed the issue I was experiencing.

    (The jump in the playroom was more than likely heat from the kitchen affecting the temperature whilst I was cooking lunch). I think you cracked it! 😃

  • @allias3g its set to call for heat at 16:30, I’ll have the data for that later today and can share them this evening.

  • @RoryFire I haven’t had to use any of the adapters when fitting the TRVs. I have gone to each radiator and made sure that the valves were opening and closing properly and recalibrated every TRV. It looks like that has fixed the problem. I’ll be keeping an eye on it over the next few days to make sure it’s working properly.

  • Sounds obvious but I would ask whether the door is open to the playroom as this would allow heat to transfer between rooms.

    One issue with these smart systems is that they give you information that you didn't have before and can make you think that things are different.