How to Fix Thermal Runaway on a 3D Printer

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Updated February 3, 2023

Whether you have a premium printer or a basic model, you should understand what causes thermal runaway on a 3D printer. Ultimately, the thermal runaway protection feature on top-tier 3D printers is good. This built-in safety feature protects the printer from damage by ensuring it is within the standard printing temperature. Runaway errors minimize the risk of fires, but it still stops 3D printing in its tracks. So, stick around to learn how to fix thermal runaways on a 3D printer.


  • Thermal runaway on a 3D printer is a safety feature that disables the printing process when the unit detects a dangerous temperature.
  • Users should keep their 3D printers clean and well-maintained to prevent thermal runaway issues.
  • You can fix inaccurate thermal protection with firmware updates and printing in a well-ventilated workspace.

Paying attention to the 3D printing material you use will help avoid hardware issues and ruined models. For example, you’ll need to learn what an all-metal hotend is if you intend to print with the best PETG filament.

Insider Tip

You should address excessive heat issues as soon as possible to prevent printer damage and ruined 3D prints.

Some materials require a high target temperature to mitigate problems like how to fix a stringing 3D printer. Additionally, understanding how to get broken filament out of a 3D printer is an excellent first step for many hardware issues.

What Causes Thermal Runaway on a 3D Printer?

Thermal runaway is a common 3D printing issue that requires immediate attention. This is a potentially dangerous error that could indicate anything from a bad temperature sensor to a firmware problem. Whether you have an entry-level 3D printer or a premium model, heat problems can cause print failures and fire hazards.

Maintain the 3D Printer

Regular maintenance can prevent a host of 3D printer malfunctions, and thermal runaway is no different. Preventative measures like cleaning the printer and reading the nozzle temperature can show you the early signs of major issues.

After cleaning the printer, check for a mispositioned thermistor wire or a malfunctioning heater block. Additionally, get a temperature reading from the heater cartridge and nozzle to ensure the correct temperature range.

Fix Firmware Issues

Thermal protection is a typical firmware feature for modern printers. This preventative measure stops the heating element when it detects a hotter temperature than the target temperature. Sometimes, outdated firmware can accidentally trigger this safety measure, resulting in print failures.


If your 3D printer malfunction points to loose or broken wires, never operate without disconnecting the power cable.

Ensure your 3D printer model has thermal runaway protection, and test the thermistor cable connectors. If the 3D printer thermistor is operating correctly, consider updating your printer firmware.

Check Your Printing Environment

The ambient temperature of your printing environment can trigger thermal protection on the 3D printer. Additionally, ensure that your print area is free from flammable materials like paper, acetone, and alcohol.

Printing in a poorly ventilated space can eventually burn out your control board and activate protection measures against extreme temperatures.

STAT: A 2019 Global EY study showed that 54% of American companies applied 3D printing tech in their businesses, making them the ninth-ranked nation for industrial 3D printing. (source)

How to Fix Thermal Runaway on a 3D Printer FAQs

How long should a 3D print take?

A 3D print job can take between 30 minutes and several days, depending on the size and complexity of the model. Additionally, consumer-grade 3D printers can struggle with some materials, increasing the time required for some models.

Is 3D printing filament a flammable material?

3D printing materials are highly flammable, especially with PLA and ABS. You should wear PPE and keep fire suppression tools nearby, even with entry-level printers.

Should I use open-source 3D printer firmware?

Open-source 3D printer firmware is generally better than proprietary options. With closed-source firmware, users must wait for their printer manufacturer to address software bugs or add features. With open-source solutions, users can rely on the 3D printing community for free updates and improvements.
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