I have a 7 yr old trane unit. The air ran just fine this summer. (we just bought the house a few months ago) however, we are now running the heat and noticed something strange. I have turned the unit OFF and the fan is still running. How can this be?

Had the same problem with my York heat pump. The repairman came out and took one look and went to the flashing led on the control board in the inside unit. It was flashing a code. He looked up the code. Fixed that problem, and the fan is now OK. He said the continual running fan was the alert to check the led for a code. Before he came out, I shut off the power to the unit for 5 minutes, all was OK for a couple of hours, then it started running all the time again.