We love our Trane, it is quiet and my wife no longer has a drafty kitchen. However, it just passed the 1 year warranty and entered our second cooling season in Chicago. We have the thermostat set at 78 degrees but it seems to run at 80 or 81 actual temperature for most of the afternoon and early evening. What has to happen to get the high cool setting to come on and bring the temperature down? How can you tell when the unit is running in high cool mode or low cool mode?