Hi all, long time tado user with a new setup question?

I've recently had a new boiler fitted (ideal logic max C35) and I'm struggling to get the system working on opentherm with my setup.

I have:-

Internet bridge V2
Smart thermostat
Extension kit
7 x TRV's

With the extension wired to the boilers opentherm connections and set up through the smart thermostat using the professional installer low voltage settings, the boiler is on constantly. This is more pump circulating/fan on anything else but interestingly the boiler isn't recognising the opentherm connection.

If I take out the extension and wire in the smart thermostat direct, then the system works fine and shows on the boiler as an opentherm connection.

This does show that tado and the boiler can work together but I obviously need the extension to work the 7 xTRV's.

The system works fine connected to the boiler stat connection but that's not the most efficient way to use it.

Anyone able to help?




  • For anyone that is interested i changed the extension for a new one and everything is fine and dandy!
    They must have updated the extensions since I originally installed mine a few years ago.
  • Hi Julian, was it easy to wire in to your new ideal boiler? Mine is about to be changed from an old Worcester to ideal.
  • johnnyp78
    johnnyp78 ✭✭✭
    Which model is it? Ideal vogue boilers are very easy to wire Opentherm, I think logic are similar.
  • johnnyp78
    johnnyp78 ✭✭✭
    Though as Julian has found, Tado have removed Opentherm support from their uk extension kits, so if you want to use it you’ll need either an EU version, to wire the smart thermostat to the boiler or to buy an old extension kit second hand.
  • Hi mark, in answer to your question, yes it was very easy from memory but I couldn't understand why it didn't work.
    The problem I had and which tado support couldn't answer was that my extension was a very early model and didn't have support for opentherm built in. I took it upon myself to replace it with an identical looking newer one and it worked straight away.
    Everything was setup through the wall thermostat.

    Hope that answers your question


  • Thanks Julian & Johnny.

    Boiler will be changed on thursday for an ideal logic.

    I have what is probably a v2 extension kit, but also have an unused v3+ starter kit hanging about the house so hopefully one way or another i'll get it working!

  • johnnyp78
    johnnyp78 ✭✭✭
    Check the extension kit has plus and minus symbols on the far right rather than saying ‘parking’. If it does you’re good to with Opentherm.
  • Hello! Can you please tell me how to connect this thermostat in OpenTherm mode? I saw that in the instructions it shows that digital + - 2 wires, what I am not clear about is that it somehow needs a 24v transformer? or do you just connect to the digital + - those 2 wires and directly to the gaz boiler open therm terminal? I mention that for power supply I have a separate cable with a plug for the outlet.

  • I think grilled cheese already answered this. You connect the two wires from + and - to the Opentherm terminal on your boiler. If it’s a wired thermostat it’s battery powered, if it’s a wireless receiver it will need a power supply, which you have.