Worcester 34CDI


I have the above boiler with 2 zones for heating - underfloor and normal thermostat controller radioators.

The thermostats for both are controlled by a Heatmiser RC1-W wireless controller linked to 2 x Heatmiser PRT - WTS controllers.

Whilst both systems are on the registration setup, i was eventually directed to contact customer services who told me that tado isn't compatible with my heating system.

Can anyone tell me if it's the boiler or the control system that is not compatible? I will happily change the control system if anyone can recommend a system that is compatible. Obviously changing the boiler isn't a realistic option!

Thanks in advance,



  • samd
    samd ✭✭✭

    @Ethelred_unread Hello - love your handle! I have a Worcester Greenstar CDI Combi working fine with tado so I cannot see how your boiler is the problem. I really know nothing at all about your controllers so can't help there but if you went back to support and said you were willing to have your combi and zones controlled by tado devices, I cannot see why they would not give you a wiring instruction.

  • Thanks for the reply. I've gone back to them and also contacted some heating engineers locally to see if they can help.

    I hoped the boiler would be compatible as it's fairly new and electronically controlled now.

    I'll update when something happens!

  • jelockwood
    jelockwood ✭✭✭
    edited August 2020

    Hopefully by now you have had a response from Tado, if so feel free to ignore the following.

    I am a mere user so I may be wrong and obviously Tado should be the relevant experts but I believe the following applies.

    The Tado Extension unit itself is a single channel controller, the Heatmiser RC1-W is a two channel controller. Your setup requires controlling two channels aka zones. With the Heatmiser setup each PRT-WTS controller is linked I believe to a different channel on the Heatmiser RC1-W and the RC1-W then independently controls each zone.

    This is or should be possible with a Tado setup but the approach will be different. With Tado you would have the Extension unit and one Tado Smart Thermostat connected to the Extension Unit wirelessly, the Extension Unit will then control the boiler and one zone. For the second (or multiple) zones you would I believe need to wire in the second Tado Smart Thermostat so it controls the zone valve rather than the Extension unit. The Extension unit would still control the entire boiler turning it off and on but one zone valve would be controlled by the Extension unit and one by a Tado Smart Thermostat.

    As both zone valves are presumably wired to your RC1-W location the Tado approach will require I believe running wires from one zone valve to the location of a Tado Smart Thermostat.

    Arguably the Heatmiser approach is simpler and more logical but equally arguably the Tado approach is more scaleable in that it can do two, three, or more zones by adding more Smart Thermostats.

  • Thanks JE, I have the heating Engineer coming out (again) on Friday to hopefully finish it off - we have been puzzling over it and have also been speaking direct to Tado on the installation line.

    Will update