Thermal runaway analysis

hello !

I'm currently having issues with thermal runaway protection, but i can't see big temperature differences in the graph on octoprint.

Moreover, the error message doesn't specify which sensor is in cause :
2018-01-28 17:53:36,357 - octoprint.util.comm - WARNING - Received an error from the printer's firmware: Thermal Runaway, system stopped! Heater_ID:

I'm running marlin 1.0.2 with the following settings for thermal runaway :
/ Parameters for all extruder heaters
#define THERMAL_RUNAWAY_PROTECTION_PERIOD 40 //in seconds
#define THERMAL_RUNAWAY_PROTECTION_HYSTERESIS 4 // in degree Celsius

// If you want to enable this feature for your bed heater,
// uncomment the 2 defines below:

// Parameters for the bed heater
#define THERMAL_RUNAWAY_PROTECTION_BED_PERIOD 40 //in seconds
#define THERMAL_RUNAWAY_PROTECTION_BED_HYSTERESIS 10 // in degree Celsius

have you some advice to determine what is the problem ?

Thanks a lot

Are u having problems with thr bed or extruder? It happened to me for the bed, i was tring to reach 110c wile with my setup i can only go for 60! if your heating bed/heater takes too long to change temperature the firmware will shut it down, increase watch_bed tem or something like it on configuration_adv!

I had the problem that my extruder temperature did not reach the set temperature after some layers (then the fan was activated). This was due to a print fan which was too effective - or badly constructed, so that it cooled also the hotend.
I solved the issue by applying a silicon cover to my hotend.

Nice!
You could also use kapton tape to cover your hotebd, or disign a pice to direct the fan air to just the layer that you're printing.