S Plan Plus/HR91s

[sideshow_bob]

Hi

We've in the middle of our extension, where we're going to be adding 2 zones of underfloor heating to our existing 3 heating zone (1 per floor)/1 vented DHW cylinder zone S Plan Plus system. The manual programmer and room stats are being replaced and we'd like to go with a smart system, having had Hive with smart TRVs on a single zone combi in our old house. We have an ideal Logic+ 30 heat-only boiler.

I'm hoping someone could clarify a small handful of questions I have before I commit to an evohome system only to find it doesn't fit our needs:

The UFH and existing zones each have dedicated motorized valves. Can someone confirm I can use BDR91/T87s for each heating zone, with a BDR91/CS92A for the DHW cylinder, and this will provide separate temperature control for each of the zones?

If I wanted to change one of the existing heating zones to have individual radiator control by HR91s, I believe I would need to put HR91s on each radiator in the zone and disconnect/leave open the motorized zone valve for this zone. Any non-HR91-controlled radiators (like towel rails) would come on whenever there is any heat demand for any of the other zones or when the DHW is heating as the motorized valve is open. Would I still be able to control the UFH and other two valve-controlled zones independently via the BDR91s/T87?

Given the 12-zone limit, can I have two or more HR91s in the same 'zone', set to a single temperature but each TRV open/close independently depending on its sensed temperature?

Thanks

[Richard]

Give us a call and we can talk to you about how the system operates and its capabilities when using different technologies on the same system.