3 Solutions to Resolve Thermal Runaway on Ender 3 (V2/Pro)

3 Solutions to Resolve Thermal Runaway on Ender 3 (V2/Pro)

Thermal runaway is one of the primary concerns for owners of 3D printers and with good reason. Beyond just damaging your printer, it can also cause a significant safety hazard. While accidents related to thermal runaways are rare, once ignited, a 3D printer fire can spread quickly throughout the house or workplace. As the name suggests, thermal runaway occurs when a problem arises in the hardware that causes it to become less capable of temperature regulation.

The Creality Ender 3 and its various versions have created a lasting impression in the 3D printing world of being some of the most reasonably priced yet packed with features. While they are praised for these qualities, they are not as well-protected against one of the most common risks a 3D printer could face – thermal runaway. 

3 Solutions to Resolve Thermal Runaway on Ender 3

There is no physical hardware that could prevent or stop this situation from occurring and further compounding the issue is that the firmware on stock Ender 3s, and even those in the higher model Pro version, lack thermal runaway protection capabilities. The V2 version has thankfully addressed this issue to some degree by incorporating appropriate measures in its default system software.

 In this article, we will go over both firmware routes as well as hardware methods in order to give you a better understanding of how to best prevent thermal runaway from occurring in your Ender 3 printer. Let’s start by talking about the health of your printer.

Regular Maintenance

The first solution to this problem is to take evasive action and check your printer by verifying all systems are running optimally.  The step-by-step assembly needs to be verified to ensure a correct setup. This means cleaning the bed, inspecting parts, and checking belts and screws as well as ensuring ventilation is clear properly to allow cooling fans to do their job. 

Special care must be taken when it comes to wiring – double-check every connection! Furthermore, ensure that the thermistor and heating cartridge are symmetrically placed on the hot end for optimal functioning and printing quality.

Once you’ve identified the two wires and verified that they are correctly placed, it’s important to lock them in. Tightening the heating cartridge screw at the underside of your hot end and the thermistor screws on its right side will hold everything firmly in place. Going through this additional step eliminates one of the common causes of thermal runaway – when a thermistor accidentally slips out from its designated heat block. 

It may sometimes seem like a nuisance to take the time for proper assembly and maintenance of an Ender 3, but it can save you from a major headache in the future! Doing regular checkups on your printer’s functionality will not only keep it in tip-top shape but will also prevent issues from occurring further down the line. Even if everything is running smoothly now, it never hurts to be proactive and make sure that your Ender 3 is still running smoothly. 

Watching the first layer of every print is another great way to ensure your printer is functioning correctly, and for long prints especially, where you may not be physically present to do so, it might be worth investing in monitoring equipment and software. This would allow you to check up on it remotely. 

Additionally, never underestimate the importance of regular cleaning and vacuuming around your printer. Not only can dust cause electrical or mechanical failures, but buildups of it can become highly flammable 


  • Inspect the wiring and assembly.
  • Ensure that the thermistor and heating cartridge are positioned in the middle of the heat block.
  • The screws on the heat block should be tightened.
  • Keep your printer up to date.
  • Keep an eye on the first layer of every print.

Securing the Firmware

The firmware for your Ender 3 contains thermal runaway protection mechanisms, which is the second option.  The firmware of your 3D printer enables the interaction between the machine’s motors, sensors, and other parts.

 It works by detecting any discrepancies between the target temperature and the actual temperature. This sensor is triggered when temperatures are too far off from one another and immediately shuts down the heating process, helping to protect both your safety and investment in the printer. Upon realizing there may be an issue within the system—a faulty or misplaced thermistor, for example— thermal runaway protection can give an invaluable warning before significant damage is done.

It’s no surprise that Creality’s popular Ender 3s has been the subject of debate over its stock firmware. Many users were left unsure over whether or not the machine featured the filament run-out feature after conflicting statements came from Creality itself. After some backtracking, Creality finally considered it included and enabled for all Ender 3s; however, this might depend on when you purchased your device since it wasn’t a guaranteed feature at one point. 

There are various methods for testing thermal runaway protection, including the step-by-step instructions provided in our article about this critical topic. 

If you’re not comfortable executing a test on your own, there is an easy way to ensure thermal runaway protection will work properly on your Ender 3 – just install Marlin firmware. Marlin contains built-in safeguards which make sure minor variations in temperature don’t lead to hazardous conditions.


  • Test your printer’s thermal runaway protection.
  • Install firmware that has thermal runaway safety enabled, such as Marlin.

Creating a Fire-Safe Environment

Finally, the third preventative measure against thermal runaway is to keep your printer in a safe place. It’s important to be sure that your printer is safe from its surroundings in order to protect its longevity and keep it functioning properly. 

The most obvious step toward avoiding danger is keeping combustible materials away from any and all heat sources. Acetone should not be stored or kept around the hot-end or printer in general as even small amounts of it could catch flame.  It is also best to have a neat workspace, especially devoid of paper products which can easily ignite if heated and result in a dangerous situation,

Also, making sure that the room is not too warm is essential in preventing any heat-related damages and malfunctions. Good ventilation is key to helping disperse any fumes and smoke that could be created during the printing process. Even with proper cooling and ventilation in place, make sure to routinely monitor the surrounding environment to ensure temperatures and airflow remain optimal for your printer’s performance.

 Additionally, by installing a smoke detector, you can be immediately alerted should smoke occur – providing you with the opportunity to take proactive action quickly. In addition, keeping a fire extinguisher close by is important too, allowing you to tackle any potential fires more effectively should the worst come to worst. 


  • Fire hazards should not be near your printer.
  • Maintain the printer in a cool location.
  • Keep your printer somewhere with good airflow.
  • Put in a smoke alarm.
  • Keep a fire extinguisher close to your printer for easy access.
Gunaseelan Murugesan
Author | Website

Experienced Project Engineer with a demonstrated history of working in the field of Product Design & Development industry in Mechanical Engineering. Skilled in 3D Printing and Re engineering Technologies with CATIA V5 , Materials Science, Finite Element Analysis (FEA), Mimics, ANSYS Workbench and Casting Simulation software. Strong engineering professional with a Master’s Degree focused in Industrial Metallurgy from PSG College of Technology, Coimbatore.

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