UFH plus radiators

[KBW]

Hello

We have built a large extension to an early 1900’s house to be heated by ASHP with buffer tank. We are installing a wet UFH system using 3 manifolds due to the position of the zones. We will also have radiators in the bedrooms in the old part of the house. Looking at various heating system designs online, I am confused as to what valves I need to install and where in the pipework. Do I need a zone valve for the radiator circuit and one for the UFH circuit? Or do I need a valve for each manifold? And should the valves be located at the buffer or at the manifolds? I have also seen some circuit drawings with non-return valves on the return legs of the UFH, presumably to stop the other circuits trying to push the wrong way.

Any advice greatly appreciated.

[KBW]

Someone must be able to help me out with this please.

[Wil]

No expert by any means, but if you have separate supply pipes to each zone, I'd valve them separately. I'd put the ZVs near the buffer and the rest of the wiring. If each manifold could call heat individually, they all need to be linked to the  same central ZV or each have their own.

 

Not seen NRVs on UFH loops as when the actuator is closed, no flow can happen in that loop?

[KBW]

That helps, thanks.

I’ll bin the NRVs and put in 3 zone valves. If each manifold has it’s own wiring centre which is linked back to the buffer tank, does it matter if I put them at the manifold end or the buffer end?

[RHayes]

NRVs would only be required to prevent pumps pulling from other zones.  For example the radiator pump pulling water back up the flow to the underfloor heating.  However this is not likely to happen if you have zone valves for each cicuit.  I would recomend putting zone valves for each manifold.  This helps prevent the above happening without NRVs and also extends the life of the UFH manifold actuators.

 

Most UFH wiring centres have a terminal for the zone vavle and therefore is often easier on the wiring to instal zone valves local to the manifolds

[KBW]

We will have a radiator circuit too. Should I put an NRV on the return leg of that to stop the UFH circuits pulling?