Hello,
I Heating unit is actinf weird today. This morning when I woke up, the fan was on and did not turn off. I check the air temperature and it was coming out cold. I noticed the thermostat was reporting 64 degrees when I usually keep it on hold at 71. I set the thermostat to Off but the fan kept on working. Then I turned it back to heater and set it to 75, went downstairs to check if the flame turned on but it did not.

So far the only way to turn the fan off is with a swithc next to the furnace. Could this be a sign the board is faulty or the egnitor es broken. Any help would be greatly appreciated.
JAD.

Post brand and model numbers.

This is more likely a sign that the high-limit control is stuck open, and other issues exist with the system. Brand and model#...

Thank you KC13, for future reference, my Heater unit was a Carrier WeatherMaker 8000. I'm attaching a link to a picture of it, you can find the High Limit switch in the middle of the picture, it's a black square way in the back http://img267.imageshack.us/img267/5155/dsc03382ht1.jpg . The technician wanted to charge me $125 for the part itself, but I found it for $31.87 through a Carrier part seller near my house. Make sure to give it at least 90 seconds for everything to reset once the part is replace.

$125.00? Sheesh! Obviously, he aspires to put his kid into one of those high-fallutin' Ivy League schools one day...