UFH Question

Just moved into a new house and brought our Wireless Starter Kit V3 with us since it worked well in our last flat. I also purchased 8 Smart Radiator valves to go on all our radiators so that is all working well now.

Over this fairly cold spell we have just had our living room has been freezing. The seller said it has underfloor heating. I asked how to control it and he said it just comes on whenever the heating to the radiators comes on (it was an old wireless thermostat which I removed and replaced with the Tado wireless thermostat.) I thought this was a little strange but never had UFH so didn’t know best practise.

So I decided to do some investigating in this hard to get into cupboard and found the manifold for the UFH. There is a Honeywell 272848 which looking online seems to be a 2 port valve for zoning the UFH which is what I would have expected. But I followed the wire from the Honeywell valve and it goes nowhere. It just terminates with the 5 wire ends connected to nothing… on the label for the Honeywell it says normally closed. So does this mean the zone is permanently closed and no hot water is going through the UFH system? I don’t know if someone could have bodged the valve to open it and then disconnected all the wires.

How would I go about connecting this up to my Tado system? One problem is the boiler is about 3 rooms away from where this hatch with the manifold is so not sure how I’m going to get the live wire from the boiler there to power this valve (assuming that is what is needed)

I’ve got pictures but couldn’t see a way to attach them here. Any advice appreciated.


  • GrilledCheese2
    GrilledCheese2 ✭✭✭
    edited March 12

    If the wires are disconnected then a normally closed motorised valve will be closed and no hot water will pass through. On one end of the valve will be a small lever. You can move this lever and permanently latch the valve in the open position. This will allow you to test the UFH is working.

    To get the system wired up properly you will need to employ a plumber. If you cannot get a wire from the motorised valve to the boiler then there are wireless systems that can be used, but better to get the link hard wired.

    If you're in England or Wales what did the seller enter on the TA6 form. If they described the heating as in good working order then I'd recommend speaking to your solicitor to recover the cost for finishing the UFH's electrical installation. This isn't an unlucky system fault, but the homeowner's failure to complete the installation to meet building regulations.

  • Thanks. I took down some plasterboard to get a better look at everything.

    So the manual open switch was already on for the 2 port valve.

    I followed the wire for the pump into an adjacent room but it just had a normal 3 pin plug on the end, but wasn’t actually plugged into any socket.

    It also seems like there are no actuators on the returns, but not sure if those are essential.

    So I could plug the pump in, but seems a bit strange that it would be running constantly even if the boiler isn’t producing any hot water.

    I probably need a control box to coordinate the 2 port valve and pump etc. but how does this all fit in with the Tado wired thermostat?

    Does the wired thermostat tell the 2 port valve to open, but then how does the 2 port valve communicate back to the main Tado boiler control to request heat?

    I couldn’t seen any specific instructions for wiring from Tado on setting it up with UFH other than it can be done.
  • There are many different ways to setup a system. Often it's a thermostat that will open a 2 port valve, when the valve is fully open there's a switch inside that can activate another device, such as the boiler. Normally the primary pump is under the control of the boiler, but there needs to be a controller to turn on any secondary pump(s). You really need a professional on site to advise on how to complete your UFH installation.

    With regards to using Tado thermostats/receiver. When the digital bus is not used they're just a switch inside that turns on/off 230V. Same as any traditional thermostat.