Can smart radiator thermostats be installed on all radiators or one needs to be left without?

Hello, can I install smart radiator thermostats on every single radiator in the house? I have so far installed on all radiators but the one in the bathroom (as per my plumber's suggestion). So I have put the Tado Wireless Temperature Sensor there instead. But it struggles to achieve the set temperature (all the other rooms achieve it brilliantly).

Does the radiator thermostat talks directly to the boiler or through the wireless temperature sensor? My boiler is Viessmann Vitodens 050-W Boka 25 just in case.

If it is OK to install a thermostat on all radiators - should the wireless temperature sensor be kept in the same room as the radiator thermostat? Would the radiator thermostat in such a case override the wireless temperature sensor one or vice versa? What in such case be the purpose of the wireless temperature sensor and where to best put it?

Many thanks,


Best Answer

  • Rob2
    Rob2 ✭✭✭
    Answer ✓

    More efficient than a radiator without thermostat is to have a "bypass" fitted, that is a pressure-opened valve which only opens when the boiler pump is running but no smart thermostat is open. That saves you from the waste of heat in the radiator without thermostat.

    Of course the real solution would be for Tado to put a software fix in the system so it never closes all valves at the same time.


  • Hi,

    Any gas safe engineer will advice, there must always be one radiator in the property that does not have a radiator thermostat fitted, as this can cause the boiler to create a fault and shut down, as I have just experienced having Tado fitted last month.

    All radiators had the Tado radiator valve fitted except one in the house, 3 days after installation, the boiler generated three faults on the lcd display and shut down, when the engineered arrived and completed some basic tests on the boiler, it was not responding as it would have normally before the Tado system was fitted. It is called balancing the central heating system.

    All that needed doing, having another gas safe engineer on the phone was adjusting the 2 valves on the (one radiator that did not have a Tado valve on it), as soon as the valves were adjusted on this radiator the boiler started to respond as it should do, once turned on.

    Job done.

    Hope this has helped.



  • Rob2
    Rob2 ✭✭✭

    Re you other question: when installing the equipment you configure separate rooms and each room can contain the smart thermostat or a temperature sensor, and one or more smart radiator valves.

    In the room with the thermostat you can configure it as the temperature sensor, in rooms without a sensor the radiator valve itself is used as the sensor. That does not work optimally in cases where it is encased or in draft, and then you add a temperature sensor and the sensor in the valve will not be used.

  • If you have a smart Thermostat, then it will/can turn off the boiler when all the valves are closed.

  • johnnyp78
    johnnyp78 ✭✭✭
    It’s not as simple as that because the valves don’t just open and close. When they’re only open a small amount it can be helpful to have a bypass to avoid locking out the boiler.
  • Thanks a lot, everyone! I have installed a bypass, so all good - have a smart radiator thermostat on every single radiator in every room and it works great :) I have got also the wireless temperature sensor, but I do not switch it on, as I do not see a point. It is now located downstairs in the middle of our open-plan kitchen/living room and is only used to identify what the temperature and humidity are in the middle, away from the 2 radiators which are on each side of this space. I am simply setting the temperature for each of these 2 radiators manually and that is fine.