Quote Originally Posted by SensibleHeatUK View Post
This is not a UK specific control system, but a Europe-wide platform, and we are the only country to "fudge" energy efficiency/building regs by adopting the S-Plan Plus approach. Honeywell argue that if you are controlling every room as a zone then the fact that you have two heating zone valves is not an issue as they can either be operated together or even removed as the zone control is now carried out at room level (and it does not matter what form of heating is used either).

It is only when you do not control every room or heat emitter that it becomes a problem, so if you use Evo you then need to decide what you want to do to make your system fit the restrictions imposed by the decisions Honeywell have made. I doubt Honeywell will spend any development time or money to change just for the UK when this can be dealt with by using more of their controls (every room fully controlled), by using two Evo controllers, or by simplifying the control approach to keep control at zone-valve level (I.e. the current building regs standard).
Very interesting. Definitely gives me some ideas.