Smart TRV's not calling for heat independently?

Hi There

My system is

Smart thermostat located in hallway. I think it's wired as it replaced old thermostat.

Extension kit

2 smart TRV's in garage and master bedroom.

The Smart Thermostat and smart TRV's have the Extension Kit set as the "zone controller"

My issue is that the radiators with smart TRV's installed aren't heating, even if the temperature I set is higher than the current temperature in the room. I think, though can't be sure that this may be happening when the room in which my smart thermostat is installed reaches temperature.

So currently my garage is set to 22 degrees but room temp is 18 degrees. The app shows 3 bars of heating for the garage, and the graph is showing as dark gray for boiler effort, but the radiator is stone cold. My hallway in which the smart thermostat is installed at is at temperature so only 1 bar on the heating

Does anyone know the issue, or what I can do? Am on support chat but it's going slowly.

As I still have 10 "dumb" rads, I don't want to set my smart thermostat to a high temperature, just to get the control over the smart TRV's, if my reading of the situation is correct (that smart thermostat is prohibiting TRV's calling for heat, when the room my thermostat is in reaches temperature).


  • You need to set the TRVs as the measuring devices for the rooms they are in, then they will call for heat themselves.

  • ms1984
    edited December 2021
    That doesn't seem to be available in the app? Have selected Settings, rooms and devices, then if I select a room I can set an offset but no measuring device (unless you mean changing the zone controller to independent?)
  • ms1984
    edited December 2021
    Unless you are saying I need to put a smart TRV in the same room (hallway) as my thermostat, then set the TRV as the measuring device in the hallway, and then the TRV's in other rooms will then work as desired?
  • From what I read I believe you have set it up correctly, but just in case:

    You need to put each TRV in their respective rooms. (Separate tile per room in the app). This will set the single TRV as the temp measuring device for the room (you don’t see it in the app). If you have more than one TRV, you have to pick one as the measuring device.

    All rooms need to have the thermostat defined as the zone controller, and it must not be set to independent (go to room, click zone controller to check the setting).

    If that is all set correctly and the problem still occurs, it could be a physical issue in that the TRVs are not capable of opening the thermostatic valves they’re mounted on. Did calibration succeed when first installing the TRVs? If not, or if you don’t remember you could check by going through the set up wizard for the TRV again.

    Reading your question again I am confused: you say you believe the thermostat is wired, but you also mention the extension kit.

    If you have a wired thermostat, the extension kit is of no use. The thermostat can control the bolier over the wire (given it is connected correctly - refer to the wizards if you need to set it up again)

    Extension kit should be connected to your boiler in the right way, if it is to control the boiler (ask for heat). The thermostat is then communicating wireless with the extension kit.

    I don’t have an extension kit myself, but it strikes me as odd that you can set it as the zone controller. I would expect the thermostat to be the zone controller of every room. (So maybe you have the thermostat as a zone controller for the hallway and the extension kit as the ZC for all other tooms? That may very well be your problem.

  • I can only set my Extension Kit as the zone controller for my smart thermostat and 2 TRV's. Maybe that means my smart thermostat isn't wired. It was installed over the old thermostat hence why I've maybe incorrectly assumed it's wired. The extension kit replaced an old hot water control/timer.

    Issue is that the radiators with the TRV's stay cold, unless my smart thermostat Room is calling for heat in which case they also heat up if below temperature. Ideally I want to be able to heat my garage (which has a smart TRV) without needing to blast heat on my remaining dumb radiators to do so. As it stands I can only get the garage to the temperature I want by heating the whole house way above the temperature I normally would.

    Not sure if anything can be done save for getting more TRV's in the house and just setting the smart thermostat to a high temp for 1 or 2 remaining dumb radiators and then regulating other rooms by keeping the temps below that of the smart thermostat
  • Pleas double check in every room what is the zone controller for that room. Is it the extension kit, or is it set to independent?

    It should be the extension kit, which drives the boiler (on behalf of any device that is assigned a room with the EK as the zone controller)

  • Here's where the TRV assignment is shown: