On Mar 11, 3:42*pm, "Triffid" wrote:

Prior to switching I was of the 'don't touch a combi with a barge-pole'
school of thought. I was persuaded by the argument that modern condensing
combis are a dramatic improvement on the earlier efforts.

It's not condensing that made combis work, it was building them of
adequate power. This has been usual practice for the last 15+ years
and competently specified combis, built by competent makers (i.e. no
Ravenheats) have worked well ever since. The old problematic ones were
just too small.

If you want a multi-fuel system with solar or solid input too, then
you do still need some sort of thermal store. If you're designing a
purely gas system, then combis are the way to go.