Too hot! Wiring issue or misunderstanding of the setup???

murphyk

I installed a tado wireless smart thermostat and extension kit last night for our upstairs heating zone. Everything went OK from a technical perspective, and instructions were easy to follow. However, I am struggling to understand what is happening in the house....

I have put smart TRV's in the bedrooms, but there are some dumb ones in hallways and towel rads etc. I assumed that the wireless smart thermostat in the master bed would control the call for heat for all the dumb rads. But that doesn't appear to be the case. All the dumb rads are blasting heat out on full throttle even though the wireless stat is not calling for heat as the master bed is above the required temp.

Should the wireless thermostat be controlling the call for heat for all the dumb rads? Or are they going to be always on from now onwards? Or have I wired it incorrectly?

There was a funky double wiring bridge in the previous wireless receiver (BDR91) which I ignored as per the instructions. But Tado instructions only show one wiring bridge in their instructions, whereas in my setup, I have two wiring bridges. L was bridged to the other L terminal (not sure of the technical term for the other L terminal. L2?) and then the second L terminal was bridged to the A terminal. Should I have wired the luster terminal differently as a consequence?

Thank you!

Toasty

Any of the smart thermostats (radiator or otherwise) can trigger demand for heat. If the heating system turns on as a consequence, all the dumb radiators will get hot (assuming the heating stays on long enough). As an added layer, the individual smart thermostats will turn off the radiator they are mounted on when they sense it is hot enough.

Can’t advise on your particular wiring, but you will get really odd behaviour if the old thermostat isn’t effectively decommissioned.

murphyk

Thank you for the reply. It makes total sense to me me. But it leads to an additional question. The radiators in the master bedroom have dumb trv's, and the room temperature is meant to be controlled by the smart thermostat. If the above is correct, that means that if ANY of the smart TRV's, or the smart thermostat, call for heat, the radiators in the master bed will come on. Is that right?

If so, that means the smart thermostat can only ever signal things are too cold in a room, but cannot do anything about it being too hot. If another room is calling for heat, that overrides the temperature control in the master bed, and the rads fire up even if they are not wanted/needed.

Is that correct? Do you have to have smart TRV's in every room where you want to control the heat?

Thanks again!

Toasty

If the above is correct, that means that if ANY of the smart TRV's, or the smart thermostat, call for heat, the radiators in the master bed will come on. Is that right?

Yes. Unless the dumb trvs turn them off.

Is that correct? Do you have to have smart TRV's in every room where you want to control the heat?

Subject to your observations above, yes. However, this isn’t as daft as it sounds. Prior to smart systems like tadoº, most people just had one thermostat in a hallway with very imprecise and slow acting trvs as some sort of balance. Having smart radiator thermostats allows you to exercise more precise control to save energy and money by not heating radiators unnecessarily. If your house is often empty, all this pales into insignificance compared with the effect of geofencing when everything goes off.

In my case, the starter kit and 10 smart radiator valves paid for themselves in three months of last winter. I think it would have taken much longer during this pandemic.

murphyk

Thank you Toasty. New smart TRV arrived today so that I can try and get the master bed under control.

Appreciate your help.