@aidar said in Heater 1 Fault (Stuck at 2000C): E0 Oops. This is the reason my thermistor was not working! I got confused. I assumed that the bed thermister was using ADC channel 0 which I also assumed was E0 on the board... but I did not realize that the bed thermistor is THERMISTOR0(ADC Channel 0), and E0 is THERMISTOR1 (ADC Channel 1). I had them off by 1. It's working now. Next step is to follow @dc42 instructions to debug the PT100 sensor to confirm it's the sensor and not the board/config. Thanks everyone!