Thanks for checking but as I posted earlier the problem of constant heat
being call for was a stuck zonal valve actuator. Once replaced
everything works perfectly. The replacement actuator was simple to
unclip from the valve, reconnect the wires and ...
It isn’t the thermostat or it’s software. One of the motorised valves
was faulty and not closing once the target heat reached. Manually closed
and all ok. Replacement unit fitted and all ok.
Thanks for your reply. I’m waiting for an engineer. Seems your right
about 3rd gen but Google/nest haven’t acknowledged any fault or even
referred to the problem. such a frustrating and irritating problem. I’ll
update if and when I get an answer.
