All of a sudden, now matter what I do with the thermostat (and I even changed that), my furnace fan motor continues to run 24/7... I can't shut it off! It is not the continuous ventilation switch on the furnace. Please help if you can

Thanks, Mark

You may have the fan relay stuck in the on position, shut off power to the unit for about 30 seconds, and power the unit back up. The unit should now fire and run correctly. At the end of the heating cycle if the main blower stays on after the burners turn off... you will have to replace the fan board / or fan relay. You didn't post the furnace model number, so I am guessing that you do not have a fan/limit switch, which is another type of fan control that as well could be bad if your furnace has that type of control...

I have noticed that my furnace runs for a very long time, it will shut down but not stay off for very long. The burners are on but at times I feel very little heat. Is this something that I can fix or should I call a service person?