"pauliepie" wrote in message
news

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?

Yep. Two 2-port valves and two Honeywell C67 programmer stats. The CM67s
energise the zone valves and the end switch of the valves switch in the
boiler. The combis will have two terminals for the room stat. The stat
simply switches the two terminals and the combi fires. That is in normal one
stat configuration. One of these terminals will give a live. Have a
permanent live from the fused spur switch to the combi to the CM67s. Out of
the CM 67s run a wire to the zone valves. Then take a wire from the live of
the combi terminal to the end switches of each zone valve. The ends
switches then have wire back to the combi's other terminal. Simple.

Or you could have one combi do upstairs and another do down. Combine the
flows to give zippo flowrates that fill a bath pronto. No zone valves then,
and if one boiler drops out, you still have another.



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