Your thermistor may not be reading correctly.

What is a thermistor and why is it important? A thermistor is a type of resistor that changes its resistance according to the temperature. It is used to measure the temperature of the hotend and the heated bed, which are important for maintaining the optimal printing conditions. If the thermistor is not working properly, it can cause inaccurate temperature readings, which can lead to poor print quality, filament jams, or even damage to the printer.

How can a thermistor degrade over time?

• Mechanical stress: The thermistor is attached to the hotend or the heated bed with a wire, which can bend or break due to repeated movements or vibrations.
• Thermal stress: The thermistor is exposed to high temperatures, which can cause it to expand and contract, resulting in cracks or fractures.
• Environmental stress: The thermistor can be affected by dust, moisture, corrosion, or oxidation, which can alter its resistance or damage its coating.

How can you tell if your thermistor is degrading? There are some signs that can indicate that your thermistor is not functioning well, such as:

• Inconsistent or fluctuating temperature readings: If your thermistor is losing its accuracy, you may notice that the temperature displayed on your printer’s screen or software is not stable or does not match the actual temperature of the hotend or the heated bed.
• Erratic or failed prints: If your thermistor is giving wrong temperature readings, you may experience problems with your prints, such as under-extrusion, over-extrusion, stringing, warping, or layer separation.
• Error messages or warnings: If your thermistor is broken or disconnected, you may see error messages or warnings on your printer’s screen or software, such as “Thermistor open”, “Thermistor short”, “MAXTEMP”, or “MINTEMP”.

How can you prevent or fix a degrading thermistor? There are some steps that you can take to prolong the life of your thermistor and avoid potential issues, such as:

• Check and clean your thermistor regularly: You should inspect your thermistor for any signs of damage or wear and tear, and clean it with a soft cloth or a cotton swab if it is dirty or dusty.
• Replace your thermistor if needed: If your thermistor is showing signs of degradation or malfunction, you should replace it with a new one as soon as possible. You can find compatible thermistors online or at your local 3D printing store. Make sure to follow the instructions on how to install and calibrate your new thermistor correctly.
• Upgrade your thermistor if possible: If you want to improve the performance and reliability of your thermistor, you can consider upgrading it to a more durable and accurate type, such as a PT100 or a thermocouple. These types of thermistors can withstand higher temperatures and are less prone to degradation. However, they may require additional hardware or firmware modifications to work with your printer.