I have a heat pump system with 5 wires on the thermostat where the yellow and white are tied together (and this system has been working fine for 2+ years). Couple questions about this setup:
1) Why are the white and yellow wires tied together?
2) I'm trying to hook up a Nest (3rd gen). Its terminals only take 1 wire. Support wasn't much help and told me that my current setup is wrong and the white/yellow wires should not be tied. How do I switch to the Nest setup properly?
picture of old setup (which is working fine):
Thank you in advance for any help!