Why is Heating Coming On when Temp Reached

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Heatsaver
Heatsaver ✭
edited January 2022 in General Questions & Topics
Hi I have a query about my new Tado system.

Why is the heating coming on when the Thermostat is set to 18.5 on the schedule and the current temperature on my phone app is showing 19.2.

So the app is reading current temp 19.2 and Heating to 18.5.

I have read the other thread about the Heating randomly coming on and I checked that Early Start is off on all Thermostats.

Thanks

Just happened again so checked at main thermostat which showed a temperature of 18.9 and heating to 18. Doesn't make sense?

Will try new batteries.

Answers

  • johnbur
    johnbur ✭✭✭
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    @Heatsaver this is what I got back from support when I asked a similar question:

    Thank you for contacting us.

    The tado° Smart Thermostat is a PID controlled thermostat. This means that tado° not only looks at the current temperature but also at the overall temperature trend.

    In other words, it will turn the heating on until the room temperature increases just above the set-point. Then the heating will remain off until the temperature starts to drop.

    In doing this, tado° can prevent your heating from switching on and off too frequently and thereby protect the boiler from excessive wear and tear. It is also much more efficient in terms of energy usage.

    It can also happen that, when tado° notices the temperature is dropping very quickly, it will start to heat in order to prevent the temperature from dropping too far below the set-point, even though the current temperature is above the set-point.
  • Heatsaver
    Heatsaver ✭
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    @johnbur Many thanks for your reply. I had an inkling it was attempted AI but not sure it stops the boiler from turning on and off a lot.
  • johnbur
    johnbur ✭✭✭
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    @Heatsaver agreed, I understand their logic, but I guess when you can have multiple rooms calling for heat at different times, there is bound to be a compromise somewhere.
  • Heatsaver
    Heatsaver ✭
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    Happening again this morning. So no radiator thermostats calling for heat and main thermostat set to 19 and reached 19.3 after approx 60 minutes of heating(cold morning). Thermostat turned off boiler.

    10 minutes later thermostat still at 19.3 and it turns heating back on so shows Heating to 19 Temperature 19.3.

    So I reduced temp to 18. Still calling for heat. So I set system to Away and boiler goes off.

    5 minutes later boiler back on.

    So I set system to frost free to turn off boiler.

    When first installed the system only called for heat when the temp dropped below the set temperature. So presumably it has been applying data to its pid algorithm over the first few weeks of use.

    At the moment it seems to be costing me more money and burning more gas. Also switching boiler on and off far to much.

    If I understand the Pid system correctly it allows for degrees of power or energy to be called from a boiler or heat system but my boiler is either on or off. Perhaps it's not suitable for this set up?

    Now I am thinking of removing it all and selling and going back to a dumb thermostat. Sad 😔
  • Pete
    Pete ✭✭✭
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    @Heatsaver
    I agree that the pid logic often/sometimes appears irrational.
    Only other factor I have found is that making adjustments and waiting for a response can often be negatively impacted by delayed comms between the trv and the bridge and/or the bridge and the extension kit.
    Ie you make a change in the app, the system appears to accept the change, but the devices carry on acting incorrectly for sometimes 15+ minutes. Sometimes missing whole heating periods but the graphs don't show and communication drop outs.
  • Mikel2
    Mikel2 ✭
    edited January 2022
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    Yeah, I am currently having a similar problem but my heating is set to "OFF" via the TADO app and the following is how TADO runs my boiler 24 hours a day, when it is switched off........... For example, I am asleep, or out of my home the boiler just runs and switches off continually at these times when I do not want my heating on.

    I switched off my heating on Saturday 8th January via the TADO app and this is how by boiler ran.........


    Off. Via the app. 13:45


    Boiler On 13:48 until 13:52. Four minutes. Then switched Off. 


    Boiler On 13:57 until 14:06. Nine minutes. Then switched Off.


    Boiler On 14:12 until 14:16. Four minutes. Then switched Off.


    Boiler On 14:22 until 14:26. Four minutes. Then switched Off.


    Boiler On 14:30 until 14:37. Seven minutes. Then switched Off.


    Boiler On 14:43 until 14:47. Four minutes. Then switched Off.


    Boiler On 14:53 until 15:02. Nine minutes. Then switched Off.


    Boiler On 15:08 until 15:12. Four minutes. Then switched Off.


    This behaviour is what happens when my heating is switched off via the TADO app and this behaviour has been present since I first installed the TADO V3+

    I have been in touch with staff at TADO via email but they do not seem to understand.

  • Heatsaver
    Heatsaver ✭
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    Happened again this morning. Scheduled temp 19, Thermostat reached 19.3 and boiler turned off.

    5 mins later it turned back on and heated to 19.8 and then turned off.

    5 mins later it turned boiler on again at which point I changed schedule temp to 18.

    I will change the scheduled temp to 18 tonight and see what it does. Maybe I will get the 19 that I want.

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