Indigo Domotics

Sounds like you have quite the system! Thanks for the tip on the C wire. What you say makes total sense. I also presume that powering the tstats with a 24v batter backup would require removing the 24v supply from the HVAC unit.

I made an edit on the prior post regarding wireless devices, in case you plan to monitor the utility like I did.

Yes, the C wire and likely the HVAC unit might need to be disconnected from the internal source. Check the wiring diagram or an expert on your system to be sure two sources won’t cause issues. I have never used an external source but I know there are kits for thermostats that require it and a wire was never ran. Beware, modern thermostats often use communication rather than specific wires to perform functions.

Thanks for the clarification. Our system is probably not using a signal wire for control because there are a good 6 wires per stat. I'm guessing on that, though.