Dealing with Hotend Thermal Runaway - Calling all 3D Printing OGs

Hi everyone! In this video I share my struggle dealing with hotend thermal runaway. I discuss different steps I took in order to try and diagnose the problem and other factors that may or may not be part of the cause. Honestly, I am no 3D printing wiz, meaning that I would like to hear your take on my issue and any wisdom that you have gained from a similar experience.
The gcode file that had the thermal runaway issue: drive.google.com/file/d/1FhI7...
Thermal Runaway i3 Series article: help.prusa3d.com/article/ther...
0:00 Intro
0:48 Talking about when the thermal runaway issue happened
1:22 Printing from SD card instead of Octoprint
2:14 Following steps in Prusa's article
4:44 Printing Benchy
5:10 Generated and printed new gcode file
6:00 Printing old gcode file again
6:43 Cold day vs. hot day
7:54 Other factors to mention
8:32 In summary
9:24 Printing the second jewelry box lid option
9:45 Byyyyyye

[@scottbaeder37]

Yes, the "cause" is the fan blowing on the block, with enough cold air that it cooled the area of the block where the thermistor is placed. So, either a warmer room (as you guessed), or a silicon sock to better insulate the block. Since you really do not want the PART cooling fan to be blowing onto the BLOCK, you might also look at the duct for the part cooling fan to make sure that it is pointing at the tip of the Nozzle, and the part.
So, it's not the "speed", but also check the fan settings, since the fan would most likely be at a higher percentage, since the faster it is moving, the more cooling that the PART would need. Glad to hear that you were able to trouble shoot the system and work the causes as to what may be causing the drop on the temperature.

[@LeonMatthews]

I concur, especially on the suggestion of a silicon sock to protect the heater block from drafts - natural or fan-forced.

[@Bat8hitcrazy]

Absolutely! The sock is a necessity for sure. That was my very first thought when I didn't see it.

[@RRLAG64]

You need a silicone sock on your heater block. Your heater block temp should always stay at its setpoint.

[@efremtommasi1387]

Had the same issue on my MK2.5S. The termistor is working good and it does its job. Check out the fan duct, maybe is oriented too high and is cooling down part of the hotend instead of filament. I fixed replacing it and lowering a bit the fan speed in the filament settings from 100% to 85% and keep the 100% only on bridges

[@claws61821]

If it's the fans, it could also be that the heat sink cooling fan is aimed too low. More likely in my opinion from what she shows us, up to the 3m30 mark at least, is that the "normal print speed" above the "initial print layers" is set too high for her machine to keep up with how much material she's extruding. It's also possible, though it doesn't match the sequence of events, that there is a kink in one of the wires leading to either her heating cartridge or her thermistor that is shorting the signal whenever her carriage crosses a certain position on the gantry.
Edit: And less than a minute later I see that she already eliminated kinks as a cause.

[@grahamwood3105]

you are very good i do like your youyub . please keep makeing more . you are the best

[@Patrick-857]

I'm usually good at picking up what an accent is. Yours has me stumped, but I'll take a guess, are you from South Africa but have lived elsewhere long enough to end up with a hybrid accent?
Great video. I had thermal runaway recently too, but it was due to me experimenting with my machine after flashing the firmware.

[@LexieEclectic]

Bingo😁 South African, I live in the US now.

[@mattiasrask1575]

I have a problem with my tevoup hydra, I replaced the hotend a little smaller than the original in connection with the replacement for a broken temp sensor and heat creep, which now if I set the heat to 200 degrees c, it runs up to 250 degrees c

[@HiECorp]

The memes are fire lol

[@fauxsoul]

I like the new one.
So it seems like it was happening when your part cooling fan kicked on, so possibly it was too cold and the fan was triggering the error.
Your hotend being at 5-10 degrees under target temperature is not normal, and not acceptable.
If you continue to have issues like this try running a PID tune while your part cooling fan is on, I think you would need to do this via octoprint as I am not sure the LCD option would let you do that.
Alternatively use a hotend sock.

[@Patrick-857]

I'm inclined to agree. I'm using a fork of Marlin now, and it uses a different thing rather than PID, which you can tune without any mucking around with Pronterface ect, and it bases everything on a map it records of the heating and cooling behavior. It seems to be very stable. I would say a silicone sock is pretty much mandatory, cooling is for the heatbreak, don't you want the hotend to be erm.... hot?