Thanks Cristian, kind of you to reach out and help. The unit is 18
months old and as it turns out- the Heatlink unit has failed,
fortunately it is within warranty. I had my electrician check it out and
he confirmed it. I rang Google who were brillian...
How did you get on? I have the same issue - cold house and H71 issue on
the thermostat. I have no lights on the heat link, so I think the unit
may have failed.