Logic Combi ESP1 35 Boiler wiring for Wired Thermostat

Hi everyone! Good morning!

I wired my tado thermostat to my wired heating system at home (Logic Combi ESP1 35 with Dual Heating Zones - 1 x front room thermostat and 1 x master’s bedroom) but it still isn’t letting me control the heating unfortunately. The current (not working) wiring / settings are:

Old thermostat Wiring (ESI ESRTP6C):

I wired the tado Thermostat as below:

RH = Live

+V = NO

0V = Parked it in P2

tado Thermostat Setup (held button for 3 seconds x 3 separate times):



HW = check

Ek = x

can someone please help to answer, ultimately:

  • why isn’t it controlling the heater/boiler?
  • Did I wire it incorrectly?
  • Did I choose the right tado setup for my system?

thank you everyone in advance!


  • I am thoroughly surprised that no one else here has a similar boiler/thermostat. I have to return my tado as I am unsuccessful in installing it.
  • rafm5
    rafm5 | Moderator


    Was tado° team unhelpful?

  • Hi rafm5,

    I wouldn’t say they were unhelpful, but, I couldn’t get the help I needed to install my devices, after spending £400 on the gear, I was expecting a but more support. I didn’t get any response from tado moderators here either unfortunately.
  • GrilledCheese2
    GrilledCheese2 ✭✭✭
    edited January 7

    @vinz420 the configuration you used would not have worked. The picture shows the wires connected to the relay control terminals, but the configuration is for Open Therm which uses the terminals on the right. You need to change D01 to R01.

    Just to add. I can’t comment on the validity of your wiring - make sure you’re not switching 240V when your boiler is setup for low voltage.

  • Hi @vinz420 ,

    I have the same thermostat and I am changing to Tado, did you work out in the end the correct wiring?

    Many thanks

  • Hi @MrD19 I didn’t get to work it out unfortunately so I had to return it. In case you get any success, would you mind sharing as I do want the tado system over Nest/Hive etc? Thanks!
  • @vinz420

    I am just trying to work out where the wires go as I cannot find any ESI wiring guide online. I just want to make sure I wire it correctly


  • So just wired it up and it is not triggering my Baxi boiler?

    I am not quite sure why? I have put black in A which was RH. Brown Which was +V in + and Grey which was 0V in -

    Should black just be parked if it was originally RH? @GrilledCheese2 are you able to help?

    Many thanks

  • @MrD19 RH is most likely the switched live used to switch on the boiler. RH means Red for Heat. You’ve connected the wires to the low voltage bus interface. Did Tado give you those wiring instructions? I’m not familiar with the esi thermostat mentioned here, but you need to be sure that you are not mixing low voltage and 230V connections.

  • @GrilledCheese2 No they didn't they basically told me the wiring for the current Thermostats is incompatible with Tado, however the boiler is compatible. So I will need to get an engineer round to wire the ESI Wiring centre box to be set to opentherm. She is saying 3 wires is Analog, even though the displays are digital.

    I have attached a picture of the wiring of the ESI Wiring centre box.

  • Hi @MrD19 . I would suggest you send that photo (preferably labelling the wires with what the PCB Board says) to tado and maybe they can assist better?

    I would also love to know a solution for this so I can buy a new set of tado Starter kit again!

    Thanks for the updates!
  • @MrD19 Opentherm? That’s a relay controlled 2 zone wiring centre with 5V PSU for the thermostats. Configuring the thermostat for relay mode and wiring as below should work

    RH -> NO

    0V -> P1

    5V -> COM

  • @GrilledCheese2

    Many thanks for your help.

    Unfortunately this still does not work so will be more then likely sending my Tado back as well. And need to research for a wired smart Thermostat that actually can replace my current one.

  • GrilledCheese2
    GrilledCheese2 ✭✭✭
    edited January 27

    That’s unfortunate it didn’t work. Your thermostat is designed to also work off a 5V USB power supply, so I was expecting RH to just switch between 0V and 5V.

    You might find that you cannot get any of the smart thermostats to work with the ESI wiring centre. In which case you will need to replace it with a standard 230V wiring centre using a dual zone S-Plan setup.

  • Hi @MrD19 I think one of the solutions I was thinking of is getting a Wireless Starter kit and see if that can work as that’s wired directly on the combi boiler, which tado said it is compatible with.
  • Hi @vinz420

    I was thinking of maybe doing the same thing? I assume I would need to send both my wired thermostats back?

  • Yes. I sent my whole lot back. Although I purchased mine through Amazon so the return process was a lot easier. I would personally love to see if that system would work and glad to hear you are thinking the same way!
  • Hi @vinz420

    I would hold fire on getting the wireless extension model as support said the following to me:

    "Unfortunately no, because tadoº Wireless Receiver is dual relay and it is not compatible with the wiring centre"

    What I don't understand, is what is compatible with the wiring centre. The problem seems to lie with that, as this is what @GrilledCheese2 was saying. I would of thought relay setup would and should work. I have even read elsewhere that people who have a similar setup, just not ESI have been successful in a relay setup

  • @MrD19 I just wanted to check if you heard the relay when you were testing. It makes a distinct click on and off, but only in relay mode. If it’s configured incorrectly for one of the digital modes then it will be silent.

  • MrD19
    edited January 28

    @GrilledCheese2 I did not hear a clicking sound, however I did configure it to RO1. I think that is the correct for relay?

  • Yes, R01 is the correct setting for relay mode. I can hear them clicking in another room so it’s quite a pronounced sound. I assume the latest hardware does the same, but they could have done something to mute the noise.

  • Really appreciate all your help. I think you are correct in what you were saying before that it is possibly the wiring centre