My gas/electric system (Bryant model 582A) is now 4 years old. It worked fine until Thanksgiving day when it stopped working. When the room temperature is below the pre-set temperature, the system starts to work but only I can hear the fan working with no warm air. A technician came in and diagnosed a bad ignitor. At first, he got a wrong part and then at second, got a right one and replaced it. It worked after the ignitor was replaced. One thing I noticed was the room temperature (68F) was higher than the pre-setting temperature (65F), which was odd to me. When the room temperature dropped below 65F, the system kick in but only the fan, no warm air again. So, I'm guessing something else is wrong instead of the ignitor. What could be the problem? We are living without heat a month and don't have any wood burning furnace. I'll be very grateful for your answer.