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Tado...low heat,pump running for hours.


Hello! I have disconnected my tado V3+ cause to be honest i did not liked the way it worked,and to be more clear and on the matter of facts,i can tell you that after the instalation( bridge+ thermostat+ wireless receiver) and let the Tado to do his work i have discovered it is very annoying and frustrating to see the Tado how at 20.5C temperature set point it is starting only the boiler pump and circulate water (for what reason dont understand ???) and water is 25C and is heating nothing,it just waiste electricity for 2-3 hour till get to the 20.3C and only then at a low heat request acording to the app it just fire the boiler for 1-2 minutes then again let only the pump to run the water and not heat at all!!!

And maibe,at 20.2 it starting very very slow to heat the water at 36 and after another 45 min it decided to go at 29 degree water temperature and finally after another 30 min it set to 20.5 and stopped....for 30 min and then again to start only the pump(due to low heat request on the app) and so go on again with the pump running for long times and not heating at all(25C water in the system heating what??) and again the same annoying routine especially at night when i hear that pump running for long periods of time. Would not be more simple to start at 0.2 under the set temp and off at 0.2 above the set point and between those set points to modulate the heat and output from the boiler?For this reason i have decided to go back to my previous controller and maibe i will give another go with Tado if you improve the way it function and the waiste of energy of running pump for hours in the night is not going to be so frustrating.

My system is: Viesmann 100 35KW B1KC and i tried to use Tado as on-off with weather compensation and external sensor(N and Com conection for receiver,sensor external at 3-4 X21 bridge on boiler) and also connected on opentherm to see how it works. I have used - + on receiver and 1-2 connectors at X21 bridge inside boiler. The same thing happend in both operation sistems,low fire and long long response,pump running for hours. And in the end i have read my gas comsumption....same,but house in other rooms where no sensors much colder with a diff of 2 degrees C. Ok...should buy more Tado's gizmos? is lost and with more i will have more i am back to simple but efficient.

Thanks for listen and pacience to read this,hope for better. All the best!

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  • I installed the Tado thermostat for a few days now and I see the same behavior. It makes no sense to me why it behaves like this. Why circulate the water without heating it?
  • @gugionut Tado algorithms require at least 0.5C temp drop to set desired temp in order to fire. Use smart schedule to set time when you want the boiler to fire and heat your home,leave this on for 1-2 hours and after off or a lower temp and the pump will be off.
  • Probably the boiler decided not to actually switch on for such low demand, while Tado thinks it is on, just very low... Would be nice to be able to tweak the behavior yourself to match your home installation.

    Similarly for valves that open a little, but not enough for water to flow in a meaningful way...
  • gugionut
    edited November 2022
    @BOG73 that’s exactly what I did.

    Moreover for the radiator thermostats Tado support said they changed the behavior for my home to always fully open regardless of heat demand and it kind of works much better now, especially in the cases when the boiler does not want to turn on heat. The not so hot water gets much faster to the radiator and heats slightly the room.

    They mentioned they can also alter the behavior so it will never trigger low heat request but they didn’t get back after this.
  • DM932187

    @BOG73 your set up is pretty much the same as mine (tado with Viessmann 100 running WC).

    Been using it for 10 years in relay. Pretty satisfactory, and substantial savings. Wouldn't set it up to run OpenTherm, even if my current v1 tado could. WC just works. tado acts as a high limiter on/off switch.

    Your v100 may be newer than mine, and may have the more advanced WC, but either way, I'd suggest you set the WC up as you like it, set tado temp to about 1C higher than you want it (so that flow temperature controls room temp, not tado), avoid deep set backs, and you should be fine.