I have a hydronic heating system (Lochnivar)that came controlled with an older (dumb) thermostat. I have 5 wires behind the wall and 5 wire in the wire packet going into heating system however only the red and white wires are connected on both sides. The remaining wires (Yellow, Green, Blue) are not connected on either end.
I'm installing a smart thermostat that needs a C-wire, where can I connect that on the circuit board of my system (picture attached)? Any advice appreciated.