Boiler reads lowest temperature of Tado radiator valve when set to Off.

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DeBroin
DeBroin
edited October 2022 in General Questions & Topics

Hello all,

I've been digging into a problem I have for the last few weeks, and I'm out of ideas. I'm hoping this community can help me.

My situation:

Generally I'm only heating all rooms in my house during the winter, when it's freezing outside and temps in the bedrooms gets too chilly. That is not yet the case, so I have my Tado Radiator valves in the bedrooms set to OFF (it's pretty much 18 to 19° Celsius in the bedrooms, so no need to heat).

My radiator valves in the kitchen and living room however, are ON, and set to 20° Celsius.

My problem:

My boiler's control panel reports that the measured temperature is 19.6° Celsius. If I check my Tado app, that is exactly the temp in the bedrooms. All other rooms are above 20°.

It also reports that the requested temperature is set to 20° (which is the value for ON valves in Tado, and my kitchen and living room valves are set to ON).

Hence, my boiler mistakenly thinks that it needs to heat, so I hear water running through the heating circuit throughout the entire house.

If I lower temps in the tado app of all radiator valves to let's say 10°, my boiler picks up that the requested temp is 10°, and the water stops running through the circuit. I turn the kitchen back to 20°, and the boiler starts again, even though in my kitchen it's warmer than 20°.

So in short: the boiler thinks the measured temperature is the temp of the lowest temperature in my house, as measured by each Tado Valve. However, it seems that the valves which are set to OFF are not properly taken into account. I would expect that the temperatures of those rooms (where the valves are OFF) isn't being taken into account by the boiler (or Tado, which I assume controls everything).

It boils down to this: if the temperature of a valve which is set to OFF, is lower than the requested temperature in another room (where the valve is ON), my boiler still tries to heat, even though it shouldn't.

My expectation is that Tado does not report the measured temperature of OFF valves to my boiler. Only the measured (and requested) temperature of the valves which are ON. If all valves are off, I'd expect my boiler to not heat anything.

I hope my explanation is a bit clear. Has anyone encountered this before, does anyone have an idea, and most importantly, is anyone able to help because this is driving me nuts. I can constantly hear my boiler trying to heat, even at night.

Answers

  • johnnyp78
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    This doesn’t sound right. What Tado equipment do you have and how is it connected to the boiler? Is your house multi or single zoned?
  • DeBroin
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    Indeed, it doesn't sound right :-) That's what's been breaking my head for the last few weeks.

    I have a Tado internet bridge, a central Tado Hub/Thermostat, and then 7 radiator valves.

    The central thermostat (represented as "Heating" in the Tado app) is connected to my Buderus Logano Plus heater/boiler.

    My house is single zoned (as in: 1 heating circuit). Hot water is also controlled via Tado.

    Sidequestion: what is the purpose of the "Heating" entity in the Tado app? I assume it's the radiator valves themselves that are driving the demand of heat. So what does that Heating do then?

  • GrayDav4276
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    Do you have any Rooms in the tado° App or is it just the "HEATING" tile ??🤔

  • johnnyp78
    johnnyp78 ✭✭✭
    edited October 2022
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    When you say central thermostat, do you mean a wired thermostat or a wireless receiver - I’m guessing it’s a wireless receiver if it’s controlling the hot water? Is it connected via relay or Opentherm?

    Have you created rooms for your trvs on the app?
  • DeBroin
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    I have a room per radiator valve (except my living room, which has 2 valves for 1 room).

    So in the Tado app I have a tile per room, plus a Heating tile, and a Hot Water tile.

    I did mean a Wired Thermostat, as in: my boiler's thermostat was mounted on the wall, and attached to the boiler itself via a wire running in my walls/floor. I installed the Tado wired thermostat instead a few years back, using that same wire, according to the guide for it back then. I believe the Tado app walked me through the steps.

    So I'm assuming the Heating tile is actually that thermostat on the wall, since the temp readouts match. I just don't know if I should put that on Heating mode, or always off.

    I hadn't heard of OpenTherm until today, so I'm assuming it's connected via relay?

  • johnnyp78
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    I think it’s probably connected via Opentherm, given that your boiler seems to have information about what your schedule is set to. I’m baffled by the heating tile - have you put the wired thermostat in a room on the app as well?

    Also in settings > rooms and devices > click on room name, make sure each is set to have the wired thermostat as zone controller and is not independent.
  • DeBroin
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    I just checked: Heating is a room. The Smart Thermostat (is it's called in the Tado app) is in that room. I can't remember though if that's something that the Tado app did by itself a few years back, or if I did that when installing.
    Every room is controlled by the same zone controller, I just checked that as well.
  • johnnyp78
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    Hmm. Check in your smart schedule if early start is turned on, and also check in your rooms settings that every trv has been put in the correct room.
  • GrilledCheese2
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    @DeBroin if your wall thermostat is in the same physical room as a smart TRV, then you need to group both devices in the same room in the App.

    If the wall thermostat is in a separate room to the smart TRVs, then it will call for heat according to its own schedule. When calling for heat it's possible that all smart TRVs will be closed and hot water is circulating for no good reason, which I think is what you are seeing.
  • DeBroin
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    @johnnyp78 early start is turned off everywhere, and every trv is in the correct room.

    @GrilledCheese2 I can move the smart thermostat to the living room in the Tado app, but I don't think it'll have any effect. Even though the smart thermostat has it's own schedule, it's always the device with the highest measured temperature. It's about 1 degree higher than the trv of the room it's in, because it's located a bit higher presumably. So it's barely ever calling for heat, and even turning it off when I can hear water through the circuit, has no effect at all.
  • johnnyp78
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    The only other thing I can think of is that there’s a problem with your boiler’s Opentherm implementation. You could try wiring the thermostat in relay and see if that makes a difference.
  • GrilledCheese2
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    Okay, sounds like the separate thermostat is not the cause. I'd still recommend you group the TRV and wall thermostat together in the living room. You will get more accurate control of the room temperature.
  • GrayDav4276
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    @DeBroin
    If you can see the temperature of your Wireless Thermostat....and also see the temperature of your Smart Radiator Thermostat, then they cannot be assigned to the same tado° Room (Tile on homepage)
    If you want the Wireless Thermostat to "control" that room then the Wireless Thermostat must be set as the room
    "Measuring Device" in 'Rooms & Devices'
  • DeBroin
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    @GrilledCheese2 @GrayDav4276 I tried changing the Smart Thermostat from the "Heating" room to the "Living Room" room, but it doesn't let me. The option to change room is greyed out. So I'm assuming this is some default Tado setting for the thermostat.


    As extra info: the plot thickens...

    I changed all Rooms, including the Smart Thermostat (Heating) to a fixed 10 degrees. My boiler reported 10° requested, and still showed the lowest room as measured temperature. But here it comes: I then changed back to how I want it (as in: living room (including the Heating room/thermostat and kitchen to a normal schedule, and all other TRV's to OFF). I have no idea why, but my boiler now reports the lowest temperature of the TRV's that are ON. I also don't hear any water running in the circuit, which I definitely did until I fixed everything at 10°.

    So it seems now everything is running as expected. I'll do more testing over the weekend, I really want to know what makes it behave erratically and what exactly fixed it.

  • GrilledCheese2
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    Did you try moving "Living Room" to "Heating"? I don't think you will be able to move Heating as it is the zone controller for your home.
  • DeBroin
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    @GrilledCheese2 no, I did not try that. Good idea, that might work