Thermal runaway - tried everything in Prusa Article, now what?
 
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Thermal runaway - tried everything in Prusa Article, now what?  

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vakil
(@vakil)
Eminent Member
Thermal runaway - tried everything in Prusa Article, now what?

I started encountering intermittent Thermal Runaway errors, checked the Prusa Article - visual inspection, connectors OK, still had the error.  I am running a Prusa i3 Mk3S+ with current firmware.  The filament is Prusament PETG which has worked fine in the past.   My printer and sensor is early 2019 and looking at the forum entries I got a new hot end thermistor, and installed it according to the instructions.   The nozzle is a hardened steel .6mm nozzle. 

I still get the error.  The ambient temperature is 21 Celsius and I was using a draft shield box I built.  I tried it without the draft shield and still got the error, although it ran a little bit longer than the previous one.  The fan is not running for the brim and first few layers but it is running when I get the error.

I have attached photos of the fan, fan shroud, and the hot end with the thermistor inserted.  

At this point I don't know what else to try.   

Thank you,

 

Attachment removed
Posted : 31/03/2021 12:53 am
Magius
(@magius)
New Member
RE: Thermal runaway - tried everything in Prusa Article, now what?

Thermistor Location

I had a similar issue when I first started printing PETG. Some items would print fine and others were triggering thermal runaway for seemingly no reason.

At the time, I was slicing everything in the center of the build plate. On the prints that failed the thermal runaway error was being triggered because the part cooling fan was cooling down the section of the bed with the thermistor beneath it. Moving the parts away from the thermistor location in the slicer solved the problem. 

Maybe this is your problem? Are you centering all of your prints or moving them around on the bed?

An easy way to test this is to slice a part that has failed in the past but make sure its located in the corner of the bed. If it completes successfully you'll have the answer as to what was triggering the thermal runaway stoppage.

Posted : 31/03/2021 1:22 am
fuchsr
(@fuchsr)
Noble Member
RE: Thermal runaway - tried everything in Prusa Article, now what?

@magius

No disrespect but that’s not a solution, that’s a band aid you put on a deeper issue without addressing it. There’s no reason you shouldn’t been able to print PETG in the middle of the sheet, I do that every day.

@vakil

You said you’ve tried everything, have you tried contacting Prusa support directly (via chat on shop.prusa3D.com)? Replaced the heater cartridge?  Could also be a logic board defect.

Posted : 31/03/2021 11:35 am
Magius
(@magius)
New Member
RE: Thermal runaway - tried everything in Prusa Article, now what?

@fuchsr

OP said they didn't know what else to try and have already replaced components to no avail. It's expensive and time consuming to just keep replacing parts and hoping. I admit it may not be a solution but it's free and easy to test. 

If a print that was failing in the center will complete when put in the corner you'll at least know the hotend components are good. Anytime you can eliminate variables while troubleshooting you are making forward progress. 

Posted : 31/03/2021 1:56 pm
vakil
(@vakil)
Eminent Member
Topic starter answered:
RE: Thermal runaway - tried everything in Prusa Article, now what?

Let me take your suggestions in order.

1. I believe I have a hot end thermal runaway but easy enough to move the test somewhere else and see.   

2. Prusa support:  I can not find a chat bot link - only email.  I have sent them one with no response but I'll try again.  If you have a link for a chat please send it.

3. Can you explain more about the heater cartridge - I am assuming you meant the block and not the sensor that I did replace.  It seems to work, gets up to temp, melts the filament, etc.  

4. Completely agree about eliminating variables.  One thing I am going to try is revering back to an earlier version of the firmware.

4. When you say the logic board, do you mean the Einsy RAMbo?   

Thank you,

Vakil

 

Posted : 31/03/2021 4:38 pm
Magius
(@magius)
New Member
RE: Thermal runaway - tried everything in Prusa Article, now what?

@vakil

Do you have a silicone sock installed on the block? I added one to stop PETG from sticking to the block and nozzle sides, but it also should help with temperature stability. 

I use this one.  https://e3d-online.com/products/v6-silicone-socks-pack-of-3?_pos=4&_sid=a44e64494&_ss=r

 

They also make a Pro version that covers more of the nozzle. https://e3d-online.com/products/v6-socks-pro-pack-of-3?_pos=5&_sid=a44e64494&_ss=r

 

Posted : 31/03/2021 4:46 pm
fuchsr
(@fuchsr)
Noble Member
RE: Thermal runaway - tried everything in Prusa Article, now what?

I don’t see why reverting the firmware should fix this but I guess it probably won’t hurt either.

Chat: it’s a floating button in the lower right corner of shop.prusa3d.com. 

Yes, I meant the Einsy board.

Heater: There are two inserts in the heater block—the heater cartridge that heats it up (thick red wire) and the thermistor that measures the temperature (thin wires). I’ve had an intermittently failing heater once. 

Posted : 31/03/2021 5:42 pm
DavidR
(@davidr-2)
Active Member
RE: Thermal runaway - tried everything in Prusa Article, now what?

I was having a thermal runaway issue after damaging and replacing the heater cartridge recently. Turned out I had blown a fuse.

Posted : 31/03/2021 10:20 pm
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