Unpredicatable thermal runaway on my CR10 S5


Hi everyone- first post here. I am hoping someone can offer a little guidance.

I have been having a thermal runaway issue on my CR10 S5. Currently I am trying to run a 50 hour PETG print and have been seeing intermittent stops. What I notice is that when I suffer one stop, there seem to be more not too far behind. Then I can go days without another one. I am terrified of committing to this big print as it will be close to $50 in filament, and the resume function really only gets me one restart after the thermal runaway hits.

Here’s a brief rundown of my rig. Couple of pics here. https://imgur.com/a/yrXq0Ri

• I am equipped with an E3D volcano, and running Marlin 1.1.9.
• Increased thermal protection hysterisis on the hot end/bed from 4c to 10c.
• I have replaced the thermistor twice now. The first replacement was definitely due, as the hotend had worn all of the insulation from my thermistor wires. I had a spare E3D unit, but was still suffering runaways. I recently put in a new bolt on thermistor from gulfcoast robotics. Temps are currently rock solid, but still I am getting these damn thermal runaways.
• I am running a little modified fan shroud from thingiverse, but as my temps appear stable, I don’t know that it’s really causing an issue. I had been running overnight prints from May-July with this set up and Marlin 1.8.x and had no issues until recently.

Currently I am sitting here with my fan blasting, hot end at 260c and bed at 60c. It’s been a couple hours. Not a peep. S3D shows temps are happily pegged without so much as 1c change in temp. Clearly, it’s waiting till I start feeding it filament :stuck_out_tongue:


Hi Riccardo,

Welcome to the forum. Dumb question: is the printer actually reporting a thermal shutdown, or is it suddenly freezing during a print. What you may be experiencing is the stepper drivers overheating, which could explain why the printer is fine with the heat on and standing still.

If you use Prontrface or Octoprint, you can monitor the temps over time on a graph to see if the thermistor is actually reporting temperature changes.

One additional thought, 260C may be pushing your printer’s power supply. Have you been able to do long prints at lower temperatures?