The Eco Home Comfort guy came this afternoon and looked things over. It was wired perfectly. He did notice that the pipes from the heat pump were cold when they should have been warm. He went back to the Nest and checked the configuration. Apparently, some heat pumps reverse the coolant flow when heating and some don’t. Mine was the other one. The resolution involved flipping 1 configuration bit, basically telling the system to do the other thing. It was cooling when it should have been heating. This explains why my house felt cold after I installed it and got colder when I turned the AUX heat off. Not only was I using the backup furnace more than I needed to, I was also making it work harder. One bit! That’s all it was.
Oh well. It was an easy fix. He looked the rest of the system over and said it looked really good. He also noted that my heating system was about nine years beyond its predicted lifespan. I’m living on borrowed time. There’s a big bill in my future. Just not today.