gas furnace blowing cold air

[docjay]

My gas furnace will run periodically ok but occasionally the air turns cold and the room temp drops well below the thermostat setting. The thermostat is blinking the temp setting calling for heat but nothing happens. When I turn off the heat switch on the thermostat and then turn it back on, it then begins to heat the air again. Is the flame going out and just blowing cold air. Any ideas?

jay

[kactuskid]

Your furnace is shutting down and when you turn the heat switch off it is resetting the safety lockout that's shutting it down. There could be a slew of reasons for the lockout, possibly a clogged flue or even a broken ignitor. It could also be due to a clogged furnace filter. Try changing the furnace filter to see if that does the trick. If it doesn't then I suggest you call an HVAC tech to come troubleshoot it for you.