Problem getting boiler to start for Heating - Water works


Hi, I've just bought the Tado starter kit with wireless thermostat.

I followed the instructions religiously and after setting everything up, on testing the system I can't get the heating to work.

Everything looks good. All the devices are there.

I have only installed the Wireless thermostat, the wireless receiver wired to the boiler and the internet bridge so far. No TRV's.

The water works fine, in override manually on the receiver, by timer or when instructed by the wireless thermostat.

But the heating simply doesn't do anything. The light on the receiver comes on and I can hear a switch, but nothing on the boiler. Ive attached the wiring below.

Can anyone make any suggestions.

The boiler is a Grant.

One other thing, the power light glows orange when the heating is fired...

I'd be grateful for any suggestions...


  • johnnyp78
    johnnyp78 ✭✭✭
    edited November 2022
    Have you checked the s plan heating/hot water valves? They can sometimes stick.
  • thanks for the reply. What are s plan hot water/heating valves sorry !

  • johnnyp78
    Have a look at this. There are two valves that control the flow of water between your radiators and your hot water tank (assuming you have an s plan system, which it looks like you do from your wiring).
  • What Johnny said, do you/did you have a regular thermostat somewhere in the mix in your setup?

    I have a similar but different problem but the root is you need the CH system energized and something calling for heat. Do you a HW cylinder in this setup somewhere? That's where my valves are. The valves in turn are operated by the thermostats and when the valves open they communicate with the boiler and say "pump on, boiler on".

    In short you may need

    System on + Thermostats calling for heat + Valves open --> Boiler and Pump.

  • Hi thanks for the response. Yes we have a hot water system. That is working perfectly with the tado. It’s simply the heating that doesn’t switch on. Everything worked perfectly with the former Honeywell controller…

  • johnnyp78
    I think it might be time to go to Tado support then, I can’t see anything obviously wrong with your wiring.
  • Thanks…and miraculously it all works this am!!! 😳