Maximum opening percent and time on radiator thermostate



  • The Fuzzy TRVs leave more heat in the radiator. It feels warmer and more pleasant. The Tado leaves no extra so the radiator is at the precise temperature Tado says.

    The full on and close off should lead to shorter heating times but it just makes it feel cooler as there is a much bigger temperature difference felt. This is why I'd also want the open/close to be a narrower range for temperature maintenance. If it is set to the extremes the heating is on and off more often. The dumb wall thermostats actually end up being better as the over shoot and fall back isn't as extreme as there is warmth above the ambient room temperature wanted remaining in the radiator.

    There is a definite need to limit each TRV to an opening and closing position range that fits the room, heating type and the comfort preferences.

  • Same problem with massive increased heat bills due to radiators rushing water through at an alarming rate, with another brand of smart thermostats.

    After a suppliers smart meter was implemented, the supply company impelled us to get our system checked for leaks! So had to change back to the old manual Danfoss ones.

    I recently discovered by accident, that the radiator valves max. input pressure can be adjusted, so I could get the Tado system.

    I am surprised this is not fixed? If product management had experienced this themselves, this would definitely be solved within the quarter. It is a really bad and very expensive experience.

    Luckily you can now return your Tado devices within 6 months, if you are not happy. But you will still have lost a lot of money on it.

  • Totally agree with Highlander, I'm considering selling my so-called smart thermostats for the same reason, now the heating season starts and if Tado doesn't fix it, I can't afford to keep the TADO "Smart system anymore.

    p.s. paste from their homepage "Let's keep heating affordable" :-(

  • AppiePau
    edited September 30

    I would like to raise my voice on this matter as well. I think it is a good idea to have Tado opening 30% when demand is low, but it should be configurable. I have been fine tuning my installation in hopes of saving some gas for the upcoming winter. My installation has now been tuned for low heat (40C max) delivery and low pumping power for more efficient gas/water conversion.

    I noticed some valves opening half way due to the low demand, but this causes annoying hissing sounds in the physical valves. Since my setup is a slow and low heat delivery, the valves can and should open fully. My boiler will boil and pump very slowly anyway. Even worse maybe, the bypass may open and the boiler be burning more gas than needed!

    So if you, Tado, needed another reason to add this feature, here it is. A simple toggle per valve would suffice for me.

  • Adjustable pins could do the job
  • AppiePau
    edited October 2

    Could be and I will consider. Maybe the valve is just poor/cheap designed and I need a new one. Just now, I noticed Tado requesting low heat (one wave) and none of the valves were open. This is not a valve issue, it's a software issue. :| I will contact support for this.

  • LynxDK, adjustable pins in not the sollution.

    I have it on one of my radiators, and the adjustment is not accurate enough.

    The Tado should do the job, else it’s not smart enough.

  • Well in my experience there are alot of things there can be the reason for something like tado telling that its opening (one wave) and no heat is comming through, and the same the other way, it should close, but dont.

    Valves get dirty inside, and the small pin in the Valve that the Tado is activationg accually need some vvs Grease, and preferable once every year for it to function 100% It can be stuck, a little bit, that since the movement of that small pin is around 6-7mm, it dosnt have to be stuck much OR the valve may sit a little loose or have moved out, before the Tado thermostat is no longer able to operate the valve at 100% Please understand, that im not saying that its that which is wrong with your setup, But its a possebility.

    I have personally been running Tado's to control my 7 Heated floor's in my house, and ive done that for 3 years with no problems at all, and i do so by the help of the FJVR Adapter i made.

    And when you install the Tado onto the valve, it will make a full open and a full close calibration. IF the tado is not mounted correctly and are sitting loose, Tado will not calibrate correctly, And it can maybe not close fully, or open fully. But lets say that its calibrating correctly and its working as it should, and now we talk about tados mounted on radiators. Then it will learn how fast it can adjust the heat, within a couple of days, which say it knows when the temperature is at a surgent point, it knows for how long it have to be fully open to reach that temperature. And it will try and correct that temperature as fast as possible so it will keep the comfort temperature.

    And thats where another problem can be, because when you have district heating, you dont want to have too water to return to the district heating, as you are paying for the temperature difference. But Tado dosnt know that, it only measuring the room temperature, and not the water. Another thing is that radiators are mostly placed benieth the windows at the outer wall of the rooms, and if you dont have brand new high insulated windows, and extremely effective insulated walls, its allways colder where the tado is measuring the temperature, so a solution to that problem could be to get a wireless sensor when you place in the middle of the room.

    Also the problem with the valve opening too much because it needs to heat the room, and in return it will let too hot water back to the district heating central, that will be especially problematic if you turn down the tempeature at night, and it suddenly have to heat the room up fast, or you open a windows, and the tado is trying to compensate.

    When i look at my tados, wheich controlls my heated floors, i can remove the tado, and then tell it to raise the temp by 1 degree, then it will accually just retract a little, and then show 1 wave, if i tell it to raise the temp by 4 degrees, it retracts all the way, and show 3 waves... its also my experience that there is not only 3 stages even tho it shows 3 waves at max... because i can adjust and i hear it move a very short time, and still showing the same wave. So im pretty sure that tado is fully capable of adjusting by a very small amount, and is allready doing so, and its doing it based on the calibration the Tado made with your valve. So it depends on the valve is functioning 100%, and if you having problem where you think its not opening enough or not closing enough, you should remount it and recalibrate.

    However that dosnt solve the problem with district heating, but here it would maybe be a solution with an adjustable pin, as with my Adapter for the FJVR Valve, i have installed a small Grub Screw, which the Pin sits in and make sure its nicely positioned for the Tado and the Valve.

    The screw is not meant to be adjustable, as its made for the FJVR Valves, which mostly is used with Floor heating. However, if the pin where adjustable, you would be able to remove a couple of millimeters from the valve movement, and accually only make the valve open like 50% where tado thinks its 100%, and that would solve the problem.

    Its important for me to say that i do not work for Tado, and i only speak from my own experience :)

    I know it was a rather long post, but i felt i wanted to share my experiences, and much of this i got when i was developing the FJVR Adapter. If anyone else have any corrections or questions, dont hold back :=)

    Best Regards Lynx

  • I have just installed new Danfoss Ra-DV valves to try to mitigate this issue. Ra-DV i a "dynamic" valve that lets you limit the flow, while keeping this set flow, regardless of pressure in the pipes (the "dynamic" part) This will hopefully let me limit the flow through the radiators to a reasonable speed, even if the TRV opens up agressively (as they do) but at the same time deliver enough heat. The great thing about this valve is its ability to keep the flow regardless of other radiators on the same line being open or not. I'm on district heating in Denmark.
    I will report my findings when I have testet for some time. But I'm curious if others have experiences with the Ra-DV valve i combination with Tado TRV's?
  • Grobsnelf
    Grobsnelf ✭✭✭
    LynxDk, they are called smart thermostat. They supposed to be smart. For district heating an with older (fully functional) valves, they are not smart enough.
    I just can’t understand, why they don’t develop this feature.
  • @Admin - any news on this? As i see it this is such a small change that would mean the whole difference to people on district heating. I am considering returning my setup if some sort of solution to this cannot be found. My system is hammering hot water through for approximately 30-45 minutes a day to then completely shut off afterwards :(
  • Alright here goes an update on my findings regarding the Danfoss Ra-DV valves.

    In short the valves seem to "slow down" tado's super agressive heating curves.
    I have them in a part of the my system where there is a pressure differential controller and a part where there is not. The most dramatic change and benefit seems to be in the part where there is no pressure differential controller. But definitely benefits both.

    It seems that by slowing down the amount of water coming through the valve, much less warm water makes it to the return. Especially beneficial in situations where the target point is more than +1c above room temp. In the morning and coming home from work an such.

    It seems that the TRVs have better time to actually detect that the temp is rising - before pouring my money out the return. And it overshoots a bit less. Still does though.

    I have a living room with two large radiators on the string with no pressure differential controller - one as the very first on the string and the other the very last. 3 other radiators between them in other rooms. This results in very high pressure on the first and almost none on the other - and here the Ra-DV's really made a difference. I have the first one highly restricted at setpoint 2 (out of 7) and the other at 6. This balances the flow between the two radiators and the return almost never becomes warm before reaching target temp, while maintaining equal amount of waterflow through them. Before - the first one would just roar and piss out the return while the last would barely get hot half way through the radiator.

    Heating does take a bit longer, naturally. But hey, Tado - this is actually what we want!

    In situations where the TRV calls for very low flow rates, below 15%ish, no water actually gets through. But this is a minor thing as Tado quickly escalates the flow when the temp is not rising as it expects.

    All in all I'm very pleased with the results, and can recommend if it makes sense in your system. I would say though that i WOULD STILL WANT A MAX % POINT. Preferably per valve or room. Please Tado.

    Bonus info. I have really gotten some great insights from using Home Assistant and looking at history graphs of their behavior. You can get insights to exactly the % called for by the TRV and the correlation to temp and overshoot.
    But if you don't use home assistant you can see the present % throughput in "Care and Protect". Realized this after maybe 6 months...

    TLDR - it mitigates the issue to an extend.
    Slows down the waste to the return. Reduced overshooting
  • Hi @Jurian
    Are there any updates regarding this request?
    Is this something that the team intends to look at or should we just forget about it?
  • Hi
    I would really appreciate if there is any news on this topic?
  • eezytiger
    eezytiger ✭✭✭

    Interesting topic. Coming from the UK I assumed that lockshield valves were completely standard. How else are you supposed to balance heat delivery throughout your system of radiators?

    I have lockshields and I've balanced my system. But this does raise an interesting point about the different needs of systems with and without lockshields.

    One frustration I have with Tado is that when a radiator requires heat - especially a radiator connected to the zone controller - the SRT might remain closed, even though that very radiator has forced the boiler on. These little incremental adjustments of valve opening may be perfect on some systems, such as these district heating systems. But they are the opposite of what is best (IMHO) for systems in which each radiator is already balanced and has a restricted flow.

    I don't need Tado to drip feed water into my radiators. If heat is required then I want an unrestricted flow from the SRT. Any restriction required will be accomplished by the lockshield. It is not appropriate for Tado to be second guessing how my system is configured and to do work that is not required or desired. Don't mess around with partial openings which may, or may not, even open the valve - unless yours is a system that would benefit from exactly this feature.

    Unfortunately, after more than one year of Tado ownership I do not think the "learning" by the system is smart enough at all. I'm not even sure that it exists. Just a week or two ago my bathroom called the boiler to fire, yet no flow through the radiator because Tado hadn't opened the valve. I know this because I have a thermometer (thermocouple) attached to the return pipe of every radiator. It did not move.

    Of course, eventually, the room would get colder, the SRT would eventually open enough for some flow, and finally the room would start heating - slowly. This is not smart behaviour. This is stupid and inefficient behaviour. Nobody wants to be heating their bypass while rooms that want heat are left to get colder. How is my system supposed to dump 9 kW minimum output through a couple of radiators when Tado is starving them of the very heat they need? Back through the bypass, round and round we go.

    This may be entering tricky territory, but maybe there should be a configurable option depending on whether you need Tado to restrict flow or if it's already taken care of. I'd prefer to be given the option myself, rather than raising a support ticket, but I do understand this might be asking for more trouble with customers who don't understand these things.