I just inspected an old Lennox G11 that had a Johnson Controls Mizer Auto Flue damper. This unit apparently fired up and failed to shut down, even after the tech arrived and removed the thermostat! In addition, the flue damper was in the closed position.
The temperature in the house got so hot that it melted most of the candles and popped a cork on a wine bottle.
Has anyone run into anything like this?