New Tado install can't turn boiler off!

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I have a new wired Starter kit V3+ and a Vaillant ecotec plus 831 combi boiler in the UK.

I'm replacing a two wire thermostat.

I have wired in my Tado using two different methods and neither of them will appear to control the boiler or turn it off. It just runs continuously.

  • first, I tried ebus which is boiler +/- to stat +/- and a bridged wire to allow the boiler to fire then set the Tado to D7 for Vaillant eBUS.
  • Next I tried the relay mode, copying the wiring given by the app to replace the old stat. Photos show wiring is reverted to original at the boiler (3 and 4 on a Valillant) and wires connected to NO and COM on the stat with the stat set back to R01.

Neither method turns the boiler off. It's a new stat and the batteries have good voltage. All screen functions work and it's connected to the bridge and I can even set it via Google assistant but no change at the actual boiler.

The only thing I can see that is off setting sequence is different to the manuals - in "EK" there is a tick, and no option to change it (no arrows underneath) and the mode (R01 / D7) is at the end of the sequence not the start. I presume this is firmware updates superseding print material.

I swapped back to the old stat and that is working as a relay as expected, kicking in and stopping the boiler.

I've got 3 TRV's in the boxes ready to go and would love to get this system up and running but not sure what more I can try. All I can think of is a) I missed something or b) it's faulty.

Can anyone offer any insight?

P.S. my current stat clicks as it gets to temp and calls for heat. There's no click from the tado at all, not sure if it's supposed to or not

Comments

  • cbd20
    cbd20 ✭✭✭
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    @Diggery I'm not familiar with eBus myself so can't comment on that side, however in relay mode based on what you've said about the configuration screen I have some thoughts.

    So the smart thermostat I believe has a latching relay. If it is responsible for controlling the boiler then you should hear the relay click on and off if it's functioning correctly.

    If, however, it is purely being used as a temperature sensor and an Extension Kit (EK) or wireless receiver is actually controling the boiler it'll permanently latch it's relay, handing control over to that other device.

    As you're saying that EK is ticked and you can't change it in the configuration, tado thinks you have/ need an Extension Kit, so it has latched the relay in the smart thermostat. That I suspect is why your heating won't switch off.

    The question is why is EK "locked" on in the configuration? This could be because it thinks you need hot water control, whereby in relay mode you would need an extension kit. In the configuration screen have you ensured that HW is set to off?
  • Diggery
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    Thanks for confirming that there should be a relay click, I thought so and mine is making no noise at all.

    Correct, EK is ticked and there is no option to change.

    From settings, I push for 3 seconds and get the following sequence

    TS - HC01 - HW X - Ek 'tick' (no option to turn off) - D05 / R01 - Save

    HW is set to off, I have tried both on and off with no difference.

    I'm contacting support to see what is up.

  • cbd20
    cbd20 ✭✭✭
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    @Diggery ah ha...TS at the start means "Temperature Sensor" so it thinks you're configuring it for wireless operation.

    Change that first setting to R01 I believe.
  • Diggery
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    Thank you! That makes sense. I don't think it was a configurable field, but I seem to be up and running now thanks to tado support. I contacted them on chat and got a reply straight away. They reset the system and I reinstalled and am up and running, with relay clicks.

    It's running on relay mode - dare I experiment with ebus mode?! Another day maybe! Will install the TRV's first.