Hi, just wondering if anyone can help me here. I have a Honeywell programmable thermostat that was installed by a professional about a year ago. About 3 days ago, the thermostat stopped maintaining a temperature and began dropping. The thermostat is showing HEAT on the display, however, no heat is being produced and the furnace is not even starting up. The only way to get the furnace to start up is to place the system in "FAN" position to run the furnace continuously. However, in "AUTO" mode (the setting I always have it) does not seem to work. I've checked all the wiring and I've even change the thermostat to a new one. Any help would be great! Thanks!