MARLIN: 66 : 4.7M High Temperature thermistor; 500 °C Thermistor; Use the latest Marlin Firmware; Marlin Firmware: is updated since version 1.1.0 RC7. Updating your firmware to the latest version will have beneficial results with print quality. #Configuration.h modification; Depending on your number of hotends, you can modify only the corresponding heater number : Find these lines and modify the values: #define TEMP_SENSOR_0 66 ; #define TEMP_SENSOR_1 66; #define TEMP_SENSOR_2 66; #define HEATER_0_MINTEMP 21; #define HEATER_1_MINTEMP 21; #define HEATER_2_MINTEMP 21; #define HEATER_0_MAXTEMP 500; #define HEATER_1_MAXTEMP 500; #define HEATER_2_MAXTEMP 500; #Configuration_adv.h modification; #define MAX_CONSECUTIVE_LOW_TEMPERATURE_ERROR_ALLOWED 5; #define MILLISECONDS_PREHEAT_TIME 30000