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Do I need the Extension kit?

I have a gas system boiler with a Megaflow for hot water storage.

I have two wired thermostats, one for upstairs and the other downstairs.

This is all currently controller via a Hortsmann Channel Plus H47XL. This has there of the for channels in use. Upsairs, downstairs and got water. All three zones can have different timing schedules.

I'm looking to install Tado but I'm really confused around if I need the extension kit? Would this replace the Hortsmann unit? Or do I leave this in place?

Best Answers

  • GrilledCheeseGrilledCheese ✭✭
    Answer ✓

    The extension kit is only able to control 2 channels and is normally a direct replacement for the the programmer - fitting on the same wiring backplate. Your Hortsmann is 4 channel programmer so it is not directly replaceable.

    Assuming the wiring for your system is a typical install you should be able to replace both wall thermostats and retain the Hortsmann. You will need to set the Hortsmann schedule for both heating zones to ‘constantly on’. The new Tado thermostats will take care of the schedule. The hot water schedule will work as now and will NOT be under the control of Tado.

    It may be possible to add the extension kit to work in parallel to the Hortsmann, giving Tado control of the Hot Water, but I think this will need some rewiring of your system - probably a professional required.

    To be honest the Hot Water schedule provided by Tado is not very smart. When you arrive home the heating switches on at the required temperature, but the hot water will only come on if it is scheduled to be on at your arrival time.

    I suggest you contact Tado support directly to get a definitive answer.


  • Thanks for the advice @GrilledCheese it's a great help.

    Being a DIY incompetent, I was going to get a professional to install it anyway. I'll ask them about the wiring being changed to also Tado to control the hot water .... but it sounds like it's not worth the effort of cost if either is high.

    So at a basic level all I need to purchase is a Start Kit + Extra Thermostat.

    And possibly an Extension if an electrician looks at the wiring and can replace the Hortsmann unit.

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