I have an interesting failure on my new Trane home system. My wife called me at work to say that the A/C is blowing hot air. When I got home I noted that the compressor was working great with hot air exhausting from the unit. Inside, the air vents were blowing a good volume of air, it was just hot. When I went into the attic I noted that the gas furnace exhaust chimney was very HOT as well as the furnace box. So I turned the system off and also turned off the gas to the unit. I restarted the unit and A/C started blowing cold air. Is it possible that the A/C and gas heater were on at the same time? I would think there would be a lock out for such things. Well I can no longer reproduce this problem and the technician will be looking at it today. It will be difficult for him to fix a working unit. Any ideas on what the problem could be?