"Thermal Runaway" error on MK4 even tho the temperature lines are perfectly straight

What is the problem?

I get "Thermal Runaway" errors from OctoPrint since I moved it from my MK3S+ to my MK4. Even tho the lines for temperature are perfectly straight.

What did you already try to solve it?

"Disable" the "Thermal Runaway" by setting it's values very high.

Have you tried running in safe mode?


Did running in safe mode solve the problem?


Systeminfo Bundle

octoprint-systeminfo-20230617121916.zip (64.9 KB)


Additional information about your setup

  • OctoPrint 1.9.0
  • Python 3.7.3
  • OctoPi 0.18.0
  • Prusa MK4 Firmware 4.6.4
  • Printer is in the Original Prusa Enclosure with the Prusa Silicon Sock on it

It's from your OctoPod plugin. I would suspect you can disable it in the settings of the plugin. You shouldn't need it to track thermal runaways as this should be built in to the printer firmware.

Yes, OctoPod gives a Warning, not an error.

2023-06-16 22:53:03,601 - octoprint.plugins.octopod - WARNING - Possible thermal runaway detected for X. Actual 28.65 and Target 36.0 

You can turn that warning off.

Thank you! This was driving me nuts. Oddly, it was only happening on my iPad and not my iPhone. I must have adjusted some settings on my phone long ago and forgot!

This is exactly a fix I had to apply to TPLink-Smartplug plugin because the X tool head termperature would never change and was always set. From what the user reported this is for ...

The "X:" is the heatbreak temperature (actual / target). Heatbreak target is set with "M142 Snn". The firmware controls the heatbreak fan speed in an attempt to keep it at or below the target temp.

The "A:" is the controller board (MK4 "buddy board") temperature. If Prusa followed the same design as for their MINI model, the thermistor is located adjacent to the high-load connection for the heated bed - but I do not have confirmation of that yet. Only actual temp is reported (target is always 0).

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