Maximum opening percent and time on radiator thermostate


To ensure not to send hot water out of the radiator, it could be helpfull to could adjust the maximum opening percentage combined with maximum opening time, followed with a minimum closing time.

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  • Falkner

    Fantastic idea.

    my valves is either fully open ro fully closed and temp. is not stable. A lot of water runs thru the radiator.

  • Thanks. Remember to give your vote to it.

    If you are member of other Tado communities, please promote the idea.

  • To make it easier to setup, it could maybe just be a maximum opening percent and then a boost function for start heating fast.

  • yes please 👍👍👍👍👍👍👍 👍
  • why would you want quicker cooling? If the valve is open it’s because the rad is heating, once it’s reached temp you want the valve to close ( and the boiler to go off ) so the hot water remains in the rad. Water would only be running through the rad if its still heating and once its reached the desired temp it will close so really can't see the point of this for the majority of users.

  • This feature is very useful for users with district heating (central heating station, that provide a lot of houser with heat) ant that is very common where Iive (Denmark). If I don’t cool the water at least 30 degree C, I have to pay extra.

    The valves on my radiators haven’t got the possibility to adjust max waterflow, and Tado thermostats just lets to much hot water running through, so it runs straight through the radiator almost without cooling.

  • Falkner

    Grobsnelf, exactly my words..

  • Exactly GrayDav4276.
  • Nikolaj
    edited January 2021

    I can totally support this suggestion.

    I too have teleheating in Denmark. The radiators in my flat are fairly old and thus very large. So, I do not have the problem of the working fluid leaving the radiator too warm. I do however have very fluctuating temperatures.

    As the temperature in my flat goes below the threshold, the thermostat obviously opens. And it closes when my flat is at target temperature. But, since the radiator is of a quite heavy making it takes in a lot of working fluid while open. After closing the temperature continues to climb, this is especially pronounced in my bedroom where the temperature generally climbs to 2,4° above target. Then down to about 0,3° below, kicks in and there we go.

    Could I limit how much the termostat opens, I believe that could remedy the situation. It would allow for the working fluid to run into the radiator more slowly, giving off more heat and allowing the thermostat more time to register the rise in temperature, thus reducing the subsequent temperature hike. This on top of remedying @Grobsnelf's issue.

    [And yes, @Grobsnelf, I did remember to upvote 😉


  • Falkner
    edited February 2021
    Hi Jurian.

    Looking foreward to a sollution.👍🏻🙂
  • Great surgestion look forward 😊
  • Great news. It very loud when it opens to full. This could be the solution.
  • I am another danish user with community central heating. This feature would be very useful

  • i am also from Denmark with community central heating, This is very essential

  • As a low Dane, I will definitely support this suggestion. It would be a great improvement for users with district heating.

    I do for sure recognise the issues mentioned above, resulting in temperature fluctuation and the radiators being quite noisy from the water flow, when the valves are open.

    I would appreciate if the lack of possibility to adjusting the water flow could be remedied in the near future.

    Quite a few of my friends have asked me, if I would recommend Tado. As of now, I do not, as they might be fined if the temperature of the water leaving the system is too hot.

    When this issue is sorted, I will definitely recommend it.

  • Hi Jurian

    I have thought a little more about this suggestion.

    The absolut important part is the maximum opening percentage. If you can develop that it would be great.

    About the functionality of this, it would be great if it could be like this:

    On each thermostat there is an option to set the maximum opening percentage.

    If the maximum opening percentage for example is set to 40%, then Tado always should reduce the opening with 60%. Tado should still show opening percentage up to 100% in the heating activity overview. If Tado for example show 50% opening, then it actually open 20% in this example.

    If you will develop more, then a boost function to coming home would be nice, with the possibility to set an over boost percentage and the time length. For example 20% over boost in 5 minutes.

    If you need help with test, you are welcome to contact me.

  • I'm seeing the same behaviour from the smart thermostats. During the day the thermostats switches between full heating for a few minutes (and overshooting a little) and an hour or two with heating off.

    In our building there are 15 apartments and a central boiler that's on all the time. This boiler is feed with hot water from a district heating system and returns the used water back. If this returned water is too hot we get an extra charge.

    Tado's current behaviour is trying to hit this extra charge instead of trying to save money. When a radiator uses full heating the central boiler sees the higher heating usage in the lower temperature of the returned water and then pumps hotter water in the pipes. Before these gets to my radiator tado has already switched them to off.

    It looks like tado's model tries to stay off as much as possible. I'd prefer a model where the smart thermostats try to avoid off and does as small movements as possible.

    For me:

    • 100 minutes at 5% is cheaper than
    • 5 minutes at 100% and 95 minutes at 0%.
  • @Grobsnelf Just as an idea, I recently had my radiators upgraded to allow for thermostatic valves. The plumber told me that the more recent plumbing (so, again, not the tado Smart Radiator valves but the stuff you put the tado valve on, no clue what the English word for that is) has wrench-adjustable settings maximizing the water flow going into the radiator. This is independent of what the tado valve does, so it's a 'hard' maximum of the water flow. I had fluctuating temperatures as well due to small room+large old radiator, until I grabbed my wrench to set the maximum to around 50% water flow. Now all is great, the room warms much easier.

    So, perhaps this is something you could try as well? It cost me around 80 euros per radiator to replace the plumbing.

  • Schippie
    edited February 2021

    Also, I really like the idea that tado is looking at a better control strategy. As I have pointed out previously, my non-smart thermostat had several features to make life easier for older houses. Hopefully tado can implement them too @Jurian :

    • Maximum pre-heat time, so the heater can only start a max of a set amount of minutes before the required heating time (mostly useful for tado's early start)
    • Heating power profile slow, medium, fast. This makes sure the heater modulates in a specific way. In my case, the slow power profile prevented a lot of ticking in the old pipes of my heating system.
    • Also applies for the cooling down ;-)
    • Maximum water temperature for heating. This also prevents my old heating system to heat up too quickly and start ticking away

    In addition to that, a bit more control on how much 'overshoot' of the set temperature to allow, would be great as well!

    When that is done too, maybe 'early start' would be a nice new feature to improve ;-)

  • In the UK our radiators usually have a manually controlled TRV on one side, and on the other they have a device similar to what you are referring to called a "radiator lock shield". It's purpose is to reduce the flow of water going through the radiator to ensure that the differential between the incoming and outgoing is between 10-20oC. It is fully manual, so if you don't adjust it and just leave it fully open it does nothing. The idea is that you use a thermometer (not done very often by plumbers, they usually just guess or use their hands to feel) to get the correct differential across the flow and return.

    In all honesty I thought this type of device would have been standard across the world, or something very similar.

    With this even if Tado opens up the valves to 100% the flow is still throttled by the lockshield and thus the returning cold water from inside the radiator is just mixed within return. I understand the logic of opening the devices a bit slower to prevent heat stress however I think this decision is probably more so about reducing the noise emitted as the winding of the servo is not a nice sound and I think most people wouldn't want to hear it going off a little every 10secs or so.

  • @Schippie if I buy a new valve, then I can adjust max flow, but not on my old valves. I could of course change my valves, but it would be much better if I could adjust it in the app. It gives the possibility to over boost the setting for a short period (if Tado will program it). Also it is a cheaper solution.

  • @gary333 some houses in Denmark also has that kind of thermostats on the outtake of the radiator, but it is a minor part.

    If you can restrict the maximum water flow, then it is no problem to ensure the cooling.

  • gary333
    edited February 2021

    Ah, I see. In the UK pretty much every single radiator will have a lockshield as it allows you to isolate the radiator at both sides before removing from the wall. Even radiators without TRV's will have lockshields either side.

    Thinking about it, this is probably why in the main all our radiators end up using vertical valves, whilst in the EU horizontal valves are more common as I see you pipe your radiators more commonly from the top, where as in the UK we tend to pipe from the bottom.

    I think someone one here might have mentioned this before, however it would be great to have a device that could measure the incoming and outgoing supply and automatically adjust the valves on the fly to suit. This would maximise the efficiency.

    In the UK our radiators are not plumbed in series but in parallel (for the most part) so whatever colder water is in the radiator will just mix with the warmer water on the return feed, so for our setups at least the heat stress isn't really a problem as the water will not cause heat stress on the boiler itself.

  • @gary333 I think it is common in the Netherlands too, although the reduction of water flow is done in the intake valve. It’s just that my particular heating system is around 60 years old so the older radiators don’t have it (yet). Since it works great I’m replacing those soon too.
  • Switching to newer valves also eliminates the annoying adapters ;-)
  • @Schippie if I buy new valves in Denmark, then I still need to use adapters.

  • Also from Denmark, and I will love this.

    at least to be able to set the maximum opening percentage. Will save me on the heating bill. 😁