Thermostat for combi boiler with radiators and underfloor heating

[Valentin Burlacu]

I am planning to have a Worcester Bosch 34CDI Classic combination boiler installed soon. Most of the house will be heated with radiators except the kitchen which has underfloor heating. The new boiler will be installed in the kitchen where the underfloor heating is located.

I already have the underfloor heating pipe installed and 50mm screed on top, but that's it. Now I believe I need to get a single circuit pump & mixing valve unit, like the one on the following link Grundfos Single Circuit Pump | Underfloor Heating plus two valves.

My confusion is around the thermostats. I am looking to be able to control the radiators and underfloor heating independently with a phone app. Not sure if I need two thermostats or one will be enough.

Will a Heatmiser neoHub with two neoStats, one for the underfloor and the other one for the radiators be a valid setup? https://www.amazon.co.uk/Heatmiser-...17152&sr=1-2-fkmr0&keywords=heatmister+neokit

If you can please advice.

Regards,

 

[Chalked]

Yes. That will work fine.
But the system will need controlling with a motorised valve on the rads, one on the ufh manifold and separate thermostat valves on the underfloor manifold.

 

[Darren Jackson]

As above, just make sure you fit zone valves and they are connected up to compatible wireless room stats to individually control them via your hub.

 

[Just a geez]

Hi there, can you run a circuit for the rads and tee off it to a normally closed 2 port zone valve for the UF circuit? Just wondering why you would need 2 zone valves?

 

[Just a geez]

Yes. That will work fine.
But the system will need controlling with a motorised valve on the rads, one on the ufh manifold and separate thermostat valves on the underfloor manifold.

With only one UF loop from the manifold do you still require a thermostatic head on the manifold? Wouldn't a blending valve do the job because there is only one UF loop?

 

[Just a geez]

I might have answered my own question above. With multiple zones being controlled by separate thermostats on at different times and temps i'm guessing that a blending valve is not the best because the temperature will vary with the additional flow so unless all the zones are balanced with flow control valves the best way is to use a thermostatic head on the UF loop and open the blending valve so that when all zones are open and calling for heat the blending valve is letting enough through to reach 50 degrees celsius on the thermostatic head??? Is this good practice or is there a risk of letting too much heat through to the manifold, i know the head will close again when it goes over a certain limit but is 80-100 degrees too much? Whats the best practice?
I assume the thermostatic head goes on the return of the loop, does it?