My furnace suddenly turned off and wouldn't respond to my thermostat so I turned off the power. I called Heat Exchanger Experts who installed and maintained the furnace for the 6 years I've owned my house. After turning it back on and inspecting it I was told these furnaces (Ducane) were of poor quality and the heat exchanger was cracked. I proceeded to have him take me down into my crawlspace and show me the crack. I didn't see it in his tiny mirror but figured he had the trained eye. My options were to have the heat exchanger replaced for $1500 or get a new furnace for $2700 after only 6 years! He continued to bad mouth the quality of the furnace and then told me he wouldn't feel safe having a child in the house. I had Fort Collins Heating and Air come out today for a 2nd opinion. Their technician found 2 loose wire connections on the circuit board that would actually account for my original problem and I had him look for the crack in the heat exchanger where the previous technician had tried to show me. He found no cracks and in his opinion my furnace was clean and running efficiently! He also did a carbon monoxide test to be safe and the reading was zero. I think you can draw your own conclusions based on the facts I have stated above. read more