Hotend randomly won't stop heating - a lot of smoke
Hi,
I recently moved, that included my MK3S+. I secured it for transport. Visually nothing is broken. However, at random the hotend won't stop heating to the point where filament starts to smoke. LCD screen shows that hotend is at 200 degree Celsius, but the fact that I see smoke makes me doubt. I did self tests couple of times, it always passes.
Problems started after the move, I secured bed cable, because it was jamming itself under the bed.
Firmware: 3.11.0-4955
Below the aftermath of such a incident:
What should I do?
Buy new hotend? New termistor? How should I troubleshoot this?
Thanks for the answers in advance 🙂
Best Answer by Hello:
That will be a thermistor problem but also probably buy a heater to
RE: Hotend randomly won't stop heating - a lot of smoke
That will be a thermistor problem but also probably buy a heater to
Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models
RE: Hotend randomly won't stop heating - a lot of smoke
Is the filament by any chance petg?
If so, the filament is most likely to contain moisture.
The smoke you see is probably steam then.
You can possibly use an external temperature meter to check if the temperature
of the heat block is the same as the value you see on the LCD screen.
RE: Hotend randomly won't stop heating - a lot of smoke
I've upgraded the firmware to the latest version. It did the thermal calibration. Now it's constantly beeping with message: "THERMAL ANOMALY".I bought new termistor and new heater. Will replace them shortly.
RE: Hotend randomly won't stop heating - a lot of smoke
Is the filament by any chance petg?
If so, the filament is most likely to contain moisture.
The smoke you see is probably steam then.
You can possibly use an external temperature meter to check if the temperature
of the heat block is the same as the value you see on the LCD screen.
It is PLA, as per my knowledge it can suck up moisture as well. Before printing I held it in drying box for 2 days. From couple of my tries one was successful, the rest turned out same as in the first post.
I do not have proper equipment to test such a high temperatures. However form my personal experience I can tell, that the temperature was well above 230 degrees Celsius, as the outcoming filament wasn't viscous but runny as water and it was boiling.
RE: Hotend randomly won't stop heating - a lot of smoke
I replaced formerly mentioned parts. As it turned out, the heater was the problem. Temperature probe was ok.
Now however I constantly have "THERMAL ANOMALY" error message. I can't finish setup wizard nor thermal model estimation.
First check all connections - especially at the Einsy end; pull and reseat all plugs.
If that doesn't work ... this could become a safety issue so contact Prusa Support:
Log into your Eshop account, navigate to Company, click Contact Us and 24/7 live Chat is one of the options.
Cheerio,
RE: Hotend randomly won't stop heating - a lot of smoke
I just had this happen to me as well. I tested today and confirmed that my thermistor is defective. Overheated by at least 50 degrees in my tests but showed normal on the display. I am still on 3.11.x so that isn't the issue. I was printing with PETG and it was running like water out of the nozzle and burning but the display showed 230 degrees.