Adding underfloor heating to existing boiler circuit

6 Nov 2008
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United Kingdom

I am about to add underfloor heating to an extension that is being built. It's about 60m2.
I have a gravity fed vented system with an S plan plus design so three two port valves for upstairs, downstairs and hot water all called for by thermostats or clock.
When the manifold arrives I am going to need to attach a flow and return to the new UFH manifold so what would be the best way to go about it?

Do I tee off the flow circuit (afterpump?) and then add another two port valve? wired to a thermostat for UFH to call it ?

For the return tee into the return of the CH system (which is also teed into HW return to I think?

Any ideas how to manage this ?

Boiler is oil fired Worcester Bosch.
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I think what I said is right. Google search found the below picture. I just need to have more wiring for the new two port valve I am going to need. Can anyone see a problem having 4 motorised valves on the system wiring?

Hoping someone can keep me right with a couple of things?
I was going to branch off existing CH flow and return and put a 2 port valve on the flow linked to clock and triggered off a thermostat?
Will the wiring work ok still I have a honeywell stc9400c can I just add some extra connector block do you think that calls the boiler and the pump when needed?

Lastly the return just needs teeing into the return and nothing else doing?

Any help appreciated


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