The thermostat doesn't tell you the temperature. It's basically a shut off for if the heat pad get above a set temp. I know with my under tank heater it can get close to 130 farenheit without the thermostat. I would go out and get a digital thermometer with a probe and tape it to the glass where the heat pad is under the substrate. I have a feeling g ur heat pad is getting hotter than you think and burning ur snake.