After much pulling of hair, I’ve installed my Heat Link and (almost) my 2nd Gen Nest stat… only I’ve run into a problem.
The issue is, the 12v wiring between Heat Link and the wall behind the Nest stat, doesn’t go directly there. It passes through the controls for the hot water and - somehow - the 12v output (I’ve tested with a multimeter, and it is 12v) is converted to 230v by the time it reaches the wall behind the Nest stat (obviously I can’t connect up the stat, or I’ll cook it).
There is another wire that does run direct from the boiler, which I thought I could use to send 12v… it does send 12v, but apparently if I don’t use the original one (that heads up to the water system) the whole heating system doesn’t work (I end up with a functional Nest stat, but no heating!
Note also, I have to wire the 230v to the Nest stat base, in the wall (no Nest attached of course), for the heating to continue working, too.
Here’s a diagram showing where I’m at. https://chemical-watch.s3.amazonaws.com/images/stat.jpg
Does anyone have an idea of how I work around this, keeping the heating working (so dealing with the need to keep the 230v wires in place), and sending a 12v feed to the stat please?
Thanks for your help/suggestions
Rich