"Christian McArdle" wrote in message
t...
Two valve to go wrong. With a combi, there is no wiring.

Yes, two valves, each costing 30 quid,

Or £40 or £50.

rather than a 3 port valve modified
just enough by the combi manufacturer for the express purpose of being
able
to charge 150 quid for it.

Combi's use diverter valves and not all are £150. There are combi's that do
not have 3-way valves at all. A conventional system needs valves.