In what steps can the radiator valve regulate heat? And for the thermostat?


So what I'd like to know:

  • In what states can the radiator valves be? Is it fully open, half open, closed? Or are there different options
  • What do the three wavy lines mean? Do they correspond to the valve states or to the required power from the heater?

I'm trying to better understand how tado works to optimize my own setup, so some insights here would surely help.

Best Answer

  • Schippie
    Answer ✓

    Hi guys, as I said before I asked Jurian from tado to confirm that the smart radiator valves really offer more control over the hot water flow than open/closed. His answer (translated of course ;-): the tado valves modulate from 0% to 100% in 5% steps.

    Seems clear enough to me.



  • Thanks. I believe you of course @GrayDav4276. I just hoped someone would give a more palatable answer. I find it so hard to believe Tado would only allow open and closed. On the face of it, it seems incredibly dumb to not implement more fine grained control. On the other hand, it’s not as if the algorithm would be able to take advantage of it 😉. Still weird though.
  • Just to be sure, I asked customer service as well. Let’s see
  • Well, I still have questions outstanding from January 2nd, so it might take a while.

  • Jup indeed 😉. I have actually asked several questions, none of which are answered yet
  • I made the mistake of not logging the ticket ID's + dates for all my questions, so I can't even realistically ask for updates.

  • Klaus_Ludwig
    edited February 2021

    I have done a couple of operational checks on my system, deliberately targetting those radiators that were at the time indicating what I take to be a partial "demand percentage" under Care and Protect.

    I step dropped the set point to well below actual temperature on a couple that were showing less than 20% demand. Both times I heard the motor operate for significantly less time than it takes for the valve to fully open or full close and the "demand percentage" immediately dropped and disappeared.

    However, I did later observe that frequently changing the set point does not always elicit an immediate response from the valve actuator motor though there is a reasonably quick response on the indicated demand percentage.

    From what I can see, contrary to what has been quoted from Tado, the valves do partially open, and are not just fully open or fully shut, but there appears to be a control limit on the valve reposition timing, which makes sense from a battery conservation point of view.

    In my very basic set up I have no variable demand signal linking my Tado to my boiler. If my radiators put out more heat then my boiler modulates accordingly. My radiators put out more heat when the flow through them increases. If the wavy lines change, then indeed demand is changing, but control on my system happens when the valves move. If there is demand there must logically be control.

    I would be interested to hear what Tado has to say on this.

  • I too anticipate a further answer to this question. sometimes its a long burst of sound from the trv like first thing in the morning when the schedule calls for several degrees increase & other times it's short bursts like when its trying to maintain temp. open a door in the current minus outside temps and the valve in that room will shut with a long sound of the trv motor working, once the timer expires another long burst to open and deliver heat then shorter bursts as the room gets back to temp and the trv prevents the room from over heating.

    the potential for over heating seems too great if these devices are just on/off, but I'm no expert..

  • tadouser1000
    edited February 2021
    Agree with the comments here about short/long motor noise from TRVs. I've noticed a strong correlation between short motor sounds from TRV and cooler radiator vs long sound and hot radiator (my boiler is running in relay mode so water temperature is constant)
  • samd
    samd ✭✭✭

    @Schippie Great - well done. I suppose it follows that they can open/close in multiples of 5%

  • There should be a faq including details like this otherwise it’s just myth.

  • I just asked for additional clarification given that someone else from tado claimed only 0%/100% was possible.

    I really hope the 5% thing is the actual case, sounds more sensible than open/close only.

    However, my plumber/installation guy also claimed they only open/close.
  • I personally appreciate any efforts that are being made by Jurian and others at Tado to engage with the community. 

    My guess is that there are a limited number of people at Tado who will have a detailed knowledge of absolutely every technical and developmental aspect and also that there may be the occasional error in their responses to the community, but I would prefer open, honest and authentic engagement with the community with the occasional error to no engagement at all.  

    Even though it has now been "confirmed" that the valves step open and closed rather than only fully open or close, we still don’t know if this is by virtue of a timed pulse signal with the only feedback being for full open and full closed or if the actuators use a positioner which relies on a feedback signal (eg from a potentiometer or proximity sensor) to accurately postion the valve according to a controller signal output. Noted that the percentages on my Care & Protect page are frequently not in steps of 5%, but that would appear to be demand rather than valve position… I had originally assumed it was the latter.

  • Hi @GrayDav4276,

    I agree with your sentiment. It would indeed be good if we could have occasional ad-hoc “official” tech oriented updates/clarifications from Tado for those of us who are interested in more detail. There is a fair degree of speculation and some frustration evident on the forum…

    I am gradually learning more about Tado as time goes on. I see that the company was founded by a few “whizz kids” in 2011 and that in 2017 a “seasoned” CEO was bought in who has experience of scaling up companies. One of their favourite sound bites seems to be that the management are keen on Tado being Hardware Agnostic.

    We are probably relatively early adopters in the scheme of things. There is significant growth potential for Tado if they get it right and I suspect that any company that is growing at any pace may experience some issues including the customer service type. 

    You can be sure that the senior Tado management will be glancing through this forum from time to time even though they are highly unlikely to engage as this is not their level.

  • Hi @GrayDav4276 interesting points. I do know that calibrating involves fully opening and closing, maybe that will serve as the 0% / 100% markers? Anyway, might be a good idea if you could try asking customer service too.

  • cbd20
    cbd20 ✭✭✭
    I suspect that while the tado valve motor has the ability to move in 5% increments, that won't manifest itself as a 5% step on the actual valve pin.

    The calibration is probably just to find the end stops - i.e how many of its 5% "steps" it needs to get from fully open to fully closed. On some valves it may be fully closed before the tado motor has reached its full extent (and arguably that's probably what you want to ensure the valve is definitely closed).

    Either way, the answer would suggest that the tado valve does allow partially open, which is what we all suspected. It just may be that the scale varies for different models of valve.
  • Oooh you’re right of course @GrayDav4276, forgot indeed.