I guess the wafer in the hovabator is bad. From what I have read they are a hollow bi-metal type. The instructions ( that I downloaded from GQF) state to plug it in, then crank it down until the switch goes off. Then back off 4 complete turns and let the temp rise ( which doesnt take long) and start adjusting. I have been adjusting in teensie increments and its either 120 degrees or 80 degrees. No in between. The switch is working fine and the contacts are good. The wiring is fine. I pulled out the wafer and subjected it to the wife's hair dryer. IT showed no signs of expansion at all. A new one is about 8 bucks. I guess I will get one coming.