I have had an evohome setup for a while now, using zone valves per floor and per UFH zone, and have been considering replacing with HR92's. As I've looked into my setup in more detail I realise that the UFH aspect is unconventional.

Basically it is using a Heatmiser UF2 controller connected to 3 relays, in turn connected to the manifold actuators.

The system does basically work....set points come on and the floor heats up, though boiler demand lags behind the set points which is not what I would expect with the Optimum Start option set. There are other oddities which I dont know whether or not they are related:
  • boiler is often fired for some part of a period when I can see that all zone set points are below actual temp.
  • 1 of the UFH zones sometimes remains warm long after it should be off, longer than a natural cool down would suggest.

My question is, is this a fundamentally flawed setup? What specifically would I gain from using the recomended Evo UFH controller that i am missing by using a 3rd party controller?

In principle I would still expect the UFH relays to honour the 'optimum start' setting and attempt to warm up the floors in advance, though I realise without 'knowing' they are connected to a UFH system they might apply the 'wrong' learning logic. Is there more to it than that?