Scott, I am waiting on the water to cool back down and then I will check the difference in water level, also I will refill to original water level and keep record of how much water was lost. Last winter I observed the percolating one day and I immediately added water, however the same thing happened. The water level does not get low enough to show up on the monitor light. I did have the draft control ( fan cover ) break. I replaced it quickly. I just don't understand why the volume of water is percolated out. When the unit cools off , I believe the water level will be below the dipstick that is used to monitor the water level. I know the water temp is not getting too high, I stole out my wife candy therm and checked the water temp as compared with the led readout on the burner, they were reading within 10 - 15 degrees of each other. That should be close, as I was checking at a different level than where the thermistor is located. Thanks for the reply.