Multizone Installation Help

We have just had an extension built and have adjusted our heating set up to include underfloor heating in the new room. The existing radiators and underfloor heating circuits are controlled by valves external to the boiler and we were expecting to have them controlled as separate zones.

We have an internet bridge and wireless extension kit, an existing smart thermostat which controlled the radiators and a new wireless thermostat which we'd like to control the underfloor heating. However, when either thermostat calls for heat only the radiator valve is actuated and the underfloor heating does not therefore receive any heat.

Each thermostat is assigned to a separate room but the only option I see for zone controller are either the wireless extension kit or independent. I assume 'independent' is for thermostats which directly control calls for demand. In our case, both are wireless and so go through the extension kit.

This has had me and our electrician pretty confused this morning. What are we doing wrong? What else can we try? Is it a case of requiring additional or different hardware?


Many thanks.