# Thermal Runaway only when printing **URL:** \ **Category:** General Discussion\ **Created:** [May 12, 2022, 8:17am UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868 "2022-05-12T08:17:50Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![JappyJan](https://avatars.discourse-cdn.com/v4/letter/j/cc9497/32.png) [@JappyJan](https://klipper.discourse.group/u/JappyJan)\ **Post date:** [May 12, 2022, 8:17am UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/1 "2022-05-12T08:17:50Z")
I use Klipper on my Ender 3 Pro. This setup worked for months without problems. Suddenly whenever i print something after reaching about 2mm Z-Height (no matter what i print), Klipper shuts down with a thermal runaway error. When i heat the nozzle without printing i can keep the temperature for hours (when making sure its not reset to 0 after the timeout) without getting any errors, also it hold the temperature just fine. I already did a PID Tune but that did not help. What can i do to figure out what the problem is, i dont want to randomly buy a new heater/thermistor without knowing that those are actuably broken… ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [May 12, 2022, 10:00am UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/2 "2022-05-12T10:00:42Z")
Hello @JappyJan ! Have you checked if the cables to the hotend are in proper shape, no lose connection, no broken cable. Also, you may share the klippy log. ---
**Author:** ![JappyJan](https://avatars.discourse-cdn.com/v4/letter/j/cc9497/32.png) [@JappyJan](https://klipper.discourse.group/u/JappyJan)\ **Post date:** [May 12, 2022, 10:29am UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/3 "2022-05-12T10:29:13Z")
Hey just checked again, and yes all cables seem to be good, no loose contacts etc. And here is my klippy.log [klippy.log](https://klipper.discourse.group/uploads/short-url/xRx93O2vcHvC5MadiqnuGj5iBZf.log) (16.6 KB) ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [May 12, 2022, 11:15am UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/4 "2022-05-12T11:15:55Z")
On what system is your Klipper running? ---
**Author:** ![JappyJan](https://avatars.discourse-cdn.com/v4/letter/j/cc9497/32.png) [@JappyJan](https://klipper.discourse.group/u/JappyJan)\ **Post date:** [May 12, 2022, 11:37am UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/5 "2022-05-12T11:37:04Z")
its a raspberry pi4 running raspbian (32 bit) klipper was installed through KIAUH.sh ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [May 12, 2022, 11:54am UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/6 "2022-05-12T11:54:30Z")
Does this support runtime logs like octoprint.log? ---
**Author:** ![JappyJan](https://avatars.discourse-cdn.com/v4/letter/j/cc9497/32.png) [@JappyJan](https://klipper.discourse.group/u/JappyJan)\ **Post date:** [May 13, 2022, 8:18pm UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/7 "2022-05-13T20:18:45Z")
i dont know what you mean by that 😕 i am not running octoprint, and i did not start with an octopi installation but with a clean raspbian installation. ---
**Author:** ![jakep\_82](https://avatars.discourse-cdn.com/v4/letter/j/ea666f/32.png) [@jakep\_82](https://klipper.discourse.group/u/jakep_82)\ **Post date:** [May 13, 2022, 8:43pm UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/8 "2022-05-13T20:43:28Z")
The log you posted doesn’t contain an error. We need a log with the error to diagnose. In my experience these errors are always hardware like a loose pin or partially broken wire, or the hotend or bed can’t maintain temperature when the cooling fan turns on. A log with the error would make it possible to determine the likely cause. ---
**Author:** ![Rageq3a](https://avatars.discourse-cdn.com/v4/letter/r/9fc29f/32.png) [@Rageq3a](https://klipper.discourse.group/u/Rageq3a)\ **Post date:** [May 13, 2022, 8:52pm UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/9 "2022-05-13T20:52:28Z")
Like Jake said, I’ve had the same error if the thermistor wire comes loose. ---
**Author:** ![JappyJan](https://avatars.discourse-cdn.com/v4/letter/j/cc9497/32.png) [@JappyJan](https://klipper.discourse.group/u/JappyJan)\ **Post date:** [May 17, 2022, 1:15pm UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/10 "2022-05-17T13:15:32Z")
Sorry for the late reply, been busy a lot… Here is a link that would most definitely contain logs from a failed print [klippy.log](https://klipper.discourse.group/uploads/short-url/eLblcR4R5PRZbkemlyhigyCgyng.log) (5.8 MB) ---
**Author:** ![Sineos](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/sineos/32/18_2.png) [@Sineos](https://klipper.discourse.group/u/Sineos)\ **Post date:** [May 17, 2022, 3:08pm UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/11 "2022-05-17T15:08:47Z")
Looking at your log it seems: - You are requesting a bed temperature of 45°C - Then you increase bed temperature to 110°C - Your bed heater struggles with reaching the target but does not manage to do so until Klipper errors out Following questions: - You wrote that you get the error at Z=2mm: Do you start printing before the bed has reached its temperature? - Are you sure that a Ender 3 Pro bed even is able to reach and sustain 110°C (which is quite high for the standard Chinese beds) ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [April 24, 2024, 1:41pm UTC](https://klipper.discourse.group/t/thermal-runaway-only-when-printing/2868/12 "2024-04-24T13:41:21Z")