I have a 2 stage heat pump system. I've recently purchase a new thermostat. While doing this install, I noticed that I had ome unsed wires tucked away. Not sure what the go to, as they are purple, black, light brown and blue. To see if they were connected anywhere, I went into the garage and took off the panel and noticed those wires were cut and unused. Why are these wires unused and what would they typically be used for?