My extension kit doesn't switch off.

I work with a Tado thermostat and an extension kit. I am trying to use the relay output of the extension kit and I connect between pins 1 and 4. Immediately after start up, I get signal at PIN 4 but it never switches of? Meanwhile the thermostat switches correctly, but the extension kit doesn't switch. I have put the settings of the thermostat like this:R01; HC01; HWx; EKv; R01.

Has somebody an idea how to solve this? I already asked support, but I never get an answer to my question. They just respond with links that lead to nowhere.


  • What do you mean by it doesnt switch off? Do you mean it isn't switching the heating off?

    edited February 6

    Yes. The signal from the extension kit to my heating always stays high. I measured the contact between pins 1 and 4 of the extension kit. (When it starts up there is no contact between pins 1 and 4, but then after I get contact between 1 and 4, it nevers goes back off) It has nothing to do with my heating system. I can measure that he gets the signal from the extension get, but that signal always stays high.

  • Your extension kit is doing what I expect it to do. Pin 4 is CH ON. In a typical S-plan system the 2 channel programmer will set CH ON to 230v to provide power to the wall thermostat, which then switches its relay to turn the boiler on and off.

  • It is not a S-plan system. I want to use it with dry contacts. The extension kit is wired to the heating system, not to the thermostat. The thermostat works wireless with the extension kit.

  • It sounds like you’re using the extension kit for wireless control rather than hot water. You need to have the jumper in position 1 and change the first R01 to TS. This will configure the wall stat to work as a temperature sensor only.

  • Indeed, it is not for HW control. That is why I turned it of. But I already tried with the TS and that doesn't change anything. The relay switches on but never switches off in the extension kit.

  • If the thermostat and extension kit are paired then I would expect that config to work. I think you’ll have to persist with the support team. Unfortunate that they have done away with the telephone service.

  • I know. And I tried the chat, but that is also a disaster. And when you send an email you ave to wait days and days for an answer. And most of the time they answer totally next to the point. 🙄

  • Problem is kind a solved. Apparently the extensionkit also listens to the Radiator thermostats. My idea was that the extension kit only looks to the wireles thermostat to start the heating and that the individual Radiator thermostats only regulate the opening of the radiators and don't start the heating. (like they do when you work without extension)

    Does anybody know if this is possible?

  • Why would you want it to work like that? That's basically how a system with a wired stat and dumb TRVs works. The only extra you'd get us being able to set the TRV temps via the app but they would only take effect if the main stat had the heating running

    It can work that way as that's what mine was doing after installation but Tado quickly corrected the configuration so any TRV could call for heat
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