How to Fix Thermal Runaway Error on a CR10

Thermal runaway protection is protection against the temperature getting out of control. It is actually a piece of code in the firmware of your machine that checks to make sure that once power is being supplied to the heater, that the thermistor’s (a temperature sensor) resistance is within a specified range for a set amount of time.

The stock Creality CR-10 unfortunately comes with the thermal runaway protection disabled. But do not worry, there is a way to get the protection onto your machine.

How do I get thermal runaway protection on my stock CR-10?

Since the stock Creality CR-10 does not come with thermal runaway protection enabled, you have to download firmware that includes it. But there is a catch. In order to download the firmware for your CR-10, you will need a bootloader for the board. The bootloader allows you to directly interact with the firmware, and the good news is, is that you only have to upload the bootloader once. After the bootloader is uploaded, you can upload different firmware as many times as you want.

A lot of firmware comes with thermal runaway protection enabled, and we suggest starting with the Marlin firmware, which you can find here.

Chris’s Basement on YouTube offers a great tutorial on this process, which you can find here.

Here is the material you are going to need before you get started:

• Arduino Uno
• USB to USB
• 5 female to female jumpers
• 1 female to male jumper

How do I fix a thermal runaway error on my CR-10?

So now that you have thermal runaway protection on your CR-10, how do you fix a thermal runaway error if it ever appears?

There are a variety of things that can trigger a thermal runaway error such as:

• A defective thermistor.
• A thermistor that is not placed correctly. For example, it might not be making solid contact with the heater block.
• Defective or partially broken wires.

And there are a variety of troubleshooting methods you can go through to get rid of this error.

First check the ambient temperature of where you are printing. It is suggested that you print in an area that is greater than 68°F (20°C). For example, if you are printing in your unheated garage in the winter, it could cause the thermal runaway error if the heater doesn’t have enough power when the print cooling fan turns on.

Next ensure that your printer is not near any unintentional sources of cooling like an open window or air conditioner unit. This can cause unwanted temperature drops and trigger the thermal runaway error.

This one might seem like a no brainer, but check the thermistor to make sure it is still securely attached to the heater block. The thermistor connection can actually come loose over time, so verify that it is secure.

Make sure the fan power settings are not too high for your slicer. Also verify your material temperature settings.

Ensure that your fan shroud is not damaged. This can cause the airflow to be different than originally designed, and sometimes cause the fan to blow directly onto the air block.

Thermal runaway protection does not come automatically with the stock CR 10, so if you are looking to add that feature you will have to put some different firmware onto your printer. This can be tricky because you will also need a bootloader, but Chris’s Basement has a simple tutorial for you to follow that makes installing the firmware a breeze.

If you already have the protection and you are getting the thermal runaway error, try the troubleshooting tips above to get back on track. Sometimes the fix is as simple as repositioning the thermistor, so take your time troubleshooting and you will be back to printing in no time.