The RLV4300 has 2 black wires coming off the back. The wall has 4 colored wires to deal with:
- Yellow (first stage cooling)
- Green (indoor fan)
- Red (24 volt hot)
- White (first stage heat)

Thoughts, and even the perfect answer, would be appreciated.

Bryan

What you have is a thermostat for line voltage (120 or 240) resistance heat. It is not intended, nor will it work, for a 24 volt furnace or air conditioning system.