Help with additional 'non-todo' zones...

Hi, I have three heating zones in my house. Two are UFH based and one is controlled by a Wunda Central Connection Box (H-BOX-12 V1.2) [A] and the other by a Heatmiser UF1 Underfloor Heating Control System [B]. The other zone [C] which runs radiators upstairs was controlled by a Honeywell timer. All are connected into a Danfloss multi-connection box running back to the boiler.

I replaced the Honeywell timer with the receiver and installed TRVs and wireless thermostats all for the radiator zone. All works brilliantly.

However, the other two UFH zones [A&B] don't seem to be able to independently fire the boiler anymore. They pump, but they pump cold water unless the Tado has fired the boiler for heating in Zone C - which of course is now much more efficient and only heats on demand.

Any ideas? I am assuming that I simply need to wire the Tado receiver differently as it feels like I've created a subtle different circuit for the boiler firing somehow but I'm a novice so a bit stuck. So far, online support have basically said it's only possible to have the Tado controlling everything but I can't see that can be the case when the other zones are fundamentally independent with their own controllers...

Any help/advice greatly appreciated... especially as I'm getting it in the neck from my wife and daughter and am now having to heat the Tado zone rooms on a cycle for most of the day which means it's anything but efficient!


  • Sounds like Tado may not be fully grasping your set up.

    Before you swapped out the Honeywell programmer, did all the circuits work fully independently of one another?

    It sounds like somehow, the programmer called the boiler and each circuit room stat only separately controlled the flow to that circuit.

    How comfortable are you with taking a look in the wiring centre?

    You likely need each circuit controller wired to the valve for that circuit, to the pump (or relevant one, if you have one for each circuit) and then to send the fire call to the boiler. Currently, I think your non-Tado controllers may be wired to the valves and pumps only, and not to the boiler.

    Heath warning: I'm not a heating engineer, or spark, but that's broadly how mine's wired. Take a look at an S-plan wiring diagram online, which might help. (Yours is more complicated, but the wiring principles are the same). If you're not completely comfortable with the electrics though, call a pro, and of course, if you do rummage about in there, make sure the power is completely isolated or your family might have more to worry about than the heating!

    Good luck

  • Thanks for the response and insights. I'm reaching the same conclusion and merrily went to look at the wiring centre (with the power off). I took off the cover, looked at the wiring, gasped, put the cover back on and called in an expert who is coming next week. I'll provide an update on here. It could be that although I thought all the other zones were firing the boiler they weren't but it was masked by the use of inefficient timings on the programmable control and the efficiency of the Tado TRVs linked with the receiver to only fire the boiler when needed has now highlighted that...