In article ,
John Stumbles writes:
pauliepie wrote:
Is it possible to have the heating circuit off a combi split into 2
zones, one for a ground floor the other for upstairs.
If so, what controls are required, etc,etc?

2 * 2-port valves etc, but you'll also need a bypass (e.g. pressure
relief bypass) so when the last valve turns off and tells the boiler to
stop theres somewhere for water to go while the boiler keeps the pump
running as it cools down

I did it using a mid-position valve, so there is no mode in which
there's no flow path, without needing a bypass. I did however
design a circuit to drive the mid-position valve and boiler demand,
using two stats as input controls.

--
Andrew Gabriel