MK2.5 Thermal Runaway  

Grandpa Joe
Eminent Member

I am having "Thermal Runaway" errors. They started recently. I have an MK2.5 and broke a wire on my Thermistor. While replacing the Thermistor, I also broke a wire to the heater cartridge. ( not being careful enough I guess.).

Anyway, after all the replacements, I now have a "Thermal Runaway" problem. I have made sure that both the heater cartridge and the thermistor are tight and secure in their spots. Both are plugged in to board.

It also occurs when the first layer is printed and the second layer is starting. The fan jumps to 256 and temp drops enough to trigger the "Thermal Runaway". If I am quick enough to get to settings and turn fan setting down to about 70, the temp climbs back up, stabilizes, and the print continues.

I tried starting out with the fan set to 70 ( is this a speed or a % of maximum? - if it is a %, how does mine jump to 256 ? - does that mean 256% ? )
Anyway - I set fan to 70, started my print. At the end of the first layer, the fan again jumps to 256 and if not turned back down manually, "Thermal Runaway" hits. I was able to turn it down quickly enough to continue to print. Later on it again jumped to 256. I was able to turn it down - this time to 60 - and continue. The third time it happened, I was unable to catch it in time and the print stopped.

If I can't set the fan and have it stay at the setting, how do I control the fan speed ?

Posted : 07/04/2019 11:41 pm

Hi GrandpaJoe,

did you get the 12volt heater, to match the mk2.5's 12 volt powersupply? or did you get the 24volt heater in error?

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 08/04/2019 3:24 am
Grandpa Joe
Eminent Member

Not sure. I will try to find out.

Posted : 08/04/2019 5:22 pm
Grandpa Joe
Eminent Member

This is what was ordered
REP-E3D-40W MK2S E3D 40W 12V Heater Cartridge

Posted : 08/04/2019 5:40 pm
Active Member

did you get this resolved?

I an having issues as well, 

all of a sudden, one print fine, next print issue..........

Posted : 28/04/2019 8:55 pm
Milos V.
Honorable Member

Reduce the max fan speed in Slic3r for the filament you are using (Filemanet settings - Cooling). The command to run full speed comes from Gcode you generated.

This will give you couple of days and in between order the silicon socks for the hotend. That will solve the issue.



Posted : 28/04/2019 9:13 pm
Active Member

Is it the bed or the extruder? I have had this with the bed ever since the 2.5s upgrade.  I had a chat with support earlier this week and they said that a new firmware release, probably this week, should resolve it.  In the meantime they suggested going back to 3.5.0 which i did and it has reduced the frequency of errors (mintemp on startup and bed preheat error on second layer start).  My extruder has a silicone sock so I don't see a significant drop in the extruder temp when the parts fan starts.



Posted : 04/05/2019 12:54 pm

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