E3D v6 and the thermistor - heads up.

[Java]

I recently updated to the E3D v6 hotend. It was working quite well and I was getting great prints with it. A couple weeks ago I started a long print (8 plus hours). When I kick off long prints I like to start them in the evenings so I can check them and once they are running I go to bed.

I went down to my shop to check the print progress and I the scent of ABS was pretty strong. I looked in on the print job and it was running just fine. I went to bed.

When I checked the print in the morning, it had completed. Inspecting the part, the finish on the ABS was very dull . It looked like it was burned. The first dozen layers were fine, but you could see a clear line where the dull finish began. I shut the printer down and went off to work. When I got home later I set up another print job and started it. A few minutes later I went back to check on it and the job had not started yet. The bed had come up to temperature, but the hot-end was reading less than room temperature. Uh oh.

I figured something 1 of 2 things likely went south - the heater cartridge or the thermistor. I set the temp via MatterControl and the heater DID heat up, but the temp still read as single digits. Ok, thermistor. I replaced it yesterday and things are back to normal (sort of). It seems I have a pretty good clog I need to clear out of the nozzle.

The thing that I am concerned about, and the reason I am sharing this experience, is because I wasn't thrilled that the printer kept working after the thermistor failed. Clearly the nozzle over heated - I have no idea how hot it got, but it was hot enough to scorch the ABS. I don't know how dangerous this could have been. Any insight would be appreciated.

Am I missing a setting or is there no fail-safe to shut down the printer if the thermistor fails?

EDIT to add the failure was one of the blue thermistor wires had broken at the connector.

[KAS]

What version of firmware are you running?

[Java]

I'm pretty sure I've never updated the firmware (I think that would be .91) but I will confirm later when I get home.