Already have TRVs,c what do I for boiler control.


I have a open therm compatible Alpha etec33 plus combi boiler. It is currently connected to a Nest third gen controller wirelessly controled thru a HeatLink wired to the boiler. I already have most of my radiators equipped with Tado TRVs. I am now thinking of changing the Nest with a tado controller as well. Have a few questions
1) How does the boiler control work with TRVs, does that boiler thermostat override the schedule i have set on the TRVs?. At the moment ,I have set the Nest boiler control to a temperature on 22 Degrees between 6am and 10am. On a radiator in the study, I have a schedule which is set to 5 Degrees during the same time window, which means the room is not heated at all during 6-10am, as the Nest starts heating at 6, but the Tado on the radiator in the study stays closed. If i were to replace the Nest with a tado,v repair this set up still work, or, be will thae master thermostat/schedule on the boiler override the individual schedules on the TRV.

2) so, i already have the TRVs and router link device ) the one that connected to the router with Ethernet cable), what further pieces of Tado kit do I need to switch from Nest to Tado. I must say i don't the Tado website extremely difficult to comprehend - they don't really seen to explain b what the various white boxes are for, and for they interact be with each other.


  • samd
    samd ✭✭✭

    @rizsher In terms of your first question, when you ask tado for wiring diagrams you can also specify whether you want the boiler-controlling wall thermostat to have primacy OR for ANY tado device to be able to call for and get heat regardless of any other device's state.

    I cannot fully answer your second question but my combi boiler, of course, needs no tado device to control hot water output cos the hot tap does that!! So my Boiler-controller (tado smart wall stat) is wired directly to the Heatlink (I also had Nest) and it is that device which receives requests from all tado trvs (and for itself if it is set to measure and control a specific TRV(s)

    You might have issues if all you rads are not on tado trvs - depends where they are and how used.

  • You need a smart wall thermostat to control the boiler. When a TRV needs heat it communicates with the wall thermostat which will command the boiler to start heating water.

    In a typical installation the wall thermostat is paired with a TRV and the wall thermostat becomes the temperature sensor for the room. The TRV no longer monitors room temperature and simply opens/closes the radiator valve. The paired TRV and wall thermostat will have a single schedule.

    If you cannot locate the wall thermostat in a convenient location and hard wire it to the boiler, then you will also need a wireless receiver. The new wireless receiver operates similar to the heat link.

    Please confirm your setup with Tado before you purchase.

  • samd
    samd ✭✭✭

    @GrilledCheese2 Just a small point. OP has Heatlink so he will wire wall stat to that.

  • @samd the heat link and Tado are not compatible. If a Tado is wired to the terminals on the heat link it’s because the heat link is disabled. Personally I’d remove the Nest entirely and sell it. The money will offset the cost of a new Tado purchase.

  • samd
    samd ✭✭✭

    @GrilledCheese2 Indeed so. My error. What I was getting at was OP could wire to the Heatlink rather than direct to the boiler were such a connection to be easier due to layout etc.

  • Thanks for the pointers folks. I have now received the boiler extension kit and wireless thermostat. Not going to install anything over the holiday period fod fear of messing something up with no plumber available to sort oit the heating.

    Question is, I'm now beginning to wonder if maybe it is not a bad idea to have the boiler controlled by Nest and radiators controlled by Tado... The nest controlling the over all heating schedule based on, schedule, temperature, geofencing, presence etc...
  • samd
    samd ✭✭✭

    @rizsher There are some advantages to your suggestion and I pondered over it after (!) purchase. For reasons I wont go into here, our daily out of bed time varies day to day and with Nest, as soon as I was awake enough to get a hand out of bed, I would turn on Nest which then fed those radiators with their own schedule (Bluetooth TRVs) I can't find a way to do that with tado - Nest allowed a schedule with no start time but scheduled to turn boiler off daily at 0930.

    I've rambled a bit - hope it makes sense.

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