Thermal Runaway

[Jhlewis10]

Getting thermal runaway after installing dual part cooling fans, set to come on after layer 5.

I am guessing this is the problem.

Now that I have cooling fans do I run PID again? I did this probably a few days before the fan install.

[Roxy]

It doesn't seem to me that installing different fans would cause a Thermal Runaway problem. But... I can tell you I always relax Marlin's thermal runaway parameters.

I'm not comfortable fighting what the experts have decided as 'safe'. But I can tell you the people (experts!!!!!) that did the thermal runaway code in Marlin think the parameters should and need to be set very tight. These are people that wake up in a cold sweat in the middle of the night. They really care about this stuff. And they don't want anybody's house to burn down because they didn't detect a thermal runaway. Me??? I'm willing to put my printer somewhere it can't start a fire and I have lots of smoke detectors over it and strategically placed around the house. I feel comfortable relaxing the parameters so I don't have false triggers.

[printbus]

Getting thermal runaway after installing dual part cooling fans...Now that I have cooling fans do I run PID again?

It doesn't seem to me that installing different fans would cause a Thermal Runaway problem...

I don't remember the details of the code and I haven't looked at how it may have been updated, but *anything* that keeps a temperature reading from returning to an acceptable threshold within some time window could realistically trip thermal runaway. I think we've seen both failing power supplies and failing heaters lead to thermal runaway errors, as would the more intended failure of the thermistor/thermocouple getting loose or the heater falling away from the extruder. Turning on excessive cooling airflow could lead to the temperature dropping off, and if the control loop can't recover and get the temp back up, the firmware can't tell what's causing the low reading over time, so it'll trip IMO.

I'd rerun PID with the cooling fans on just to rule out that possibility, but I wouldn't hold my breath.

BTW - Makerfarm firmware distributions used to have thermal runaway disabled.

[Jhlewis10]

Ran my thermal camera on the printer way too much cooling on the bed, reduced fans down and started them on higher layers and so far it has not repeated.