Our Central Heating System has been on the "fritz" lately. It will work for a few hours, sometimes days kicking on and off like nomral then it will suddenly stop blowing warm air. The air is usually VERY cold, but its set on heat. There is a red light that usually starts flashing "em heat", we were told (by a repair person) that we needed to "reset" the system when this happened, which worked the first two times. The A/C works fine, never any problems with it. How do we fix this?? If anyone can help it would be greatly appreciated.