Help replacing underfloor heating control

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Hi there

I was a Tado user back in 2014 and loved it.

I’ve now moved into a house with underfloor heating and not sure if I can make it work.

We have:

Three OJ WLM3 wiring centres, with manual thermostats connected (probably low voltage) and associated room sensors/thimbles.

The OJs control actuators (one 10, one 8, one 2) and the pump.

I don’t think Tado thermostats will communicate with OJ unfortunately.

What do you think!?

Some more detail here: https://www.plumbersforums.net/threads/replacing-the-control-system-its-a-real-mess.127510 for those with any time to help! Thank you 😊

Comments

  • starconf
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    The standard way of using tado with underfloor heating is to use one wired Tado thermostat per room connected to the existing wiring/actuators, but the WLM3 uses a completely different system where all the room sensors can be connected to just a single pair of wires that 'daisy chain' between sensors without having to run wires from each sensor back to ther wiring centre. These sensors then communicate with the wiring centre using a network system similar to a computer network.

    If the 'daisy chain' method is how it has been wired then you might not be able to use Tado with your system without replacing each wiring centre with a standard one, and then running new wires to each room so you can install a wired Tado thermostat in each room.

    I don't think you can eve use Tado Smart Radiator Valves in the place of each actuator, and then have a wireless Tado Thermostat in each room, as there could be multiple issues with that. Getting the radiator valves to fit the manifold may be a problem, they're bigger than a standard actuator so may not fit. The radiator valves also open to varying ammounts depending on the heat demand in the room which works for radiators, but if you have a pumped manifold could cause problems when only one or two valves are open a small ammount and the pump is still running. You will also be running into the 25 device limit.

    I think your best options are to either stay with what you have or replace the system with one of the wireless UHF wiring centres available, although I'm not sure if they support that many heating cicuits, you might need two of them.

  • tm010
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    Hi @starconf thank you for the reply! There is, I think, one bit of good news.. the thermostats are all by the wiring centres because each room only has a thermistor.

    You are right I think on the 'daisy chain' but I believe that's only between the wiring centres and the thermostats (next door to each other).

    I've attached some photos and would love your view! Thank you.


  • starconf
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    Unfortunately it might not be as good news as you think. Those thermistors only carry a tiny current and the wires are very thin. Although the wired Tado thermostats are battery powered the wires still need to carry the power to turn on the actuator when the rooms calls for heat. I think those wires will be too thin for that, although its hard to tell from the photo if the thin wires join to standard wiring under the tape, if so you could be in luck.

    Thats quite an unusual set-up you have there anyway with all the room thermostats in one place. It might be worht getting an electrician to test the wiring and make sure all the wires go where you expect them to.