Service Bulletin: Thermistor Issue in Aerostruder and Dual Extruder v3 Tool Heads

Marlin has a PID Autotune feature. Other tutorials REPRAP and Marlin.

The new PID values were enacted in firmware version that came with Cura 2.6.66. As long as you are using Cura 2.6.69 and the accompanying firmware of then these values will be present in the software.

Afternoon my Aerostruder fell into the serial number range denoted by sticker on back of tool head range.

Unfortunately I wasn’t in the position to be able to arrange return of the head so…

I have replaced the thermistor and the wiring all the way upto the main loom plug with soldered joints I have the latest Cura LE 3 installed and the print head firmware updated through Cura and M coded as per installation instructions.

Problem is I still keep getting creeping temperatures what have I missed ? the replacement thermistor is a genuine E3D V6 thermistor.

Is this a firmware issue do I need to revert back to the last official Cura release 2.6.69 ? to get back on track ?

Thanks in advance

We have recently released Cura 3.2.21. Release notes on whats new can be found here:

The Marlin included for all printers will be the latest stable upstream branch of This is what we are currently recommending across all tool heads, and will be worth upgrading to. When installing the new Cura be sure to uninstall previous versions, and clear your cache afterwards. Operating specific instructions can be found here

Hi Brent many thanks for the reply as I mentioned I am running latest version of Cura LE 3 and as I had already swapped out all of the wiring and sensor with neat soldered joints at the loom connector and still having issue I could only guess that the issue I have is software / firmware related.

I just thought if I reverted back to the previous release to see if the problem went as this was originally a thermistor / wiring issue.

Did you check all three connection points, or just the set at the loom? On the Aero thermistor, there will be three sets of pins you will want to check:
If you replaced the thermistor with one that does not have the quick swap connector, this should not be required.

At what point in the print are you having temperature fluctuations?

Hi Brent
The complete loom has been replaced from the new thermistor to the main tool head connector.

I am beginning to suspect that the error occurs when the filament cooling fan kicks in or the tool head is not close to the bed.

Just strikes me odd its only happened since the latest release of Cura ?

I had the same issues after i sent my toolheads back to lulzbot especially with petg, pla and other materials. I ordered silicone socks from matterhackers and so far my thermal runaway problem has not come back yet.

Thanks for the link.

Was ready to make the plunge and use my Christmas “funds” for a Dual Extruder v3… but all of the issues I have been seeing has given me pause. As of December 2018 - have all the issues been worked out? When I search youtube for users who are printing with it - I can only find 1 or two who showed an initial print and they have not posted anything else about it in 6 months. My usage will be exclusively to use water-soluble filament for support structures to help with my more complicated designs. My Lulzbot has run great from DAY 1 so I am little nervous about making an update that could make it less reliable.

The LulzBot Dual Extruder V3 is a fairly solid design. Soluble filaments are iffy at best.

While I printed the test object successfully, I’m under 50% success with other parts when using soluble filament. Most likely I haven’t hit on the right settings yet.

I have approximately the same success rate with two color, same material printing using the Dual Extruder V3 as I have with the Single Extruder.

I don’t think the hardware is responsible for my soluble filament failures. I think my success rate will go up once I get the settings right.

This video (from Lulzbot) shows this as their solution for printing PVA… so I am going to trust their marketing and expect it works as they are showing. My dragon sculptures have grown so complicated this is really the only way to print some of them.

Lulzbot has not let me down yet. I will let you know how it goes…

–Update: I ordered the tool head but it says it is currently back ordered so not sure when I will actually get it in.

Tony Boutwell

I am experiencing a strange problem. The moment cooling fan kicks off temperature drops resulting thermal runaway error.
If I switch off the fan everything is ok.

I had thermal runaway issues before and fixed it by squeezing the crimps with pliers. This problem started since I switched to Colorfab XT.