Woke up this morning to a chilly house. Checked the stove and the burn pot was overflowing with pellets. The stove was cold to the touch so it was off for hours. Luckily my forced air kicked on at 60. This is the second time this has happened. I cleaned out the pellets and the stove fired rite up. What would cause it to go out overnite? It's set on a thermostat and still has the factory settings. I believe i was burning Pennington pellets. Phil