Error #2:1 - Hotend: Critical temperature

Hi. I am having an issue with my Zortrax m300 Plus. I keep getting an error #2:1 - Hotend: Critical temperature. The printer prints the raft of the part with no issue but it seems like when it is about to print the actual part, that is when the overheating error occurs suddenly. I have replaced the extruder cable, the extruder pcb and the hotend and I am still having this issue. I have attached pictures of the error I am getting and the raft that printed. The next step for me was to replace the heater and thermocouple and see if that solves the issue, but those parts seem to be out of stock for the longest while on the website. I watch the temperature on the display while it is printing the raft and it maintains at 275 degrees. When it starts to print the actual part, the print stops and the temperature suddenly shoots up to the one shown in the image.

Hi @Cmaraj,

indeed, the heater&thermocouple could be at fault. However, as the temperature suddenly rises to 400 Celsius degrees - I am wondering if the motherboard has not been affected.

Could you please, once you turn the printer on, go to heating controls (menu → tools) and check if the hotend starts heating automatically despite the fact the heating option is disabled. If yes - this could confirm the board’s failure. However, if the hotend remains cold then - I would recommend replacing the heater&thermocouple (I will ask my colleagues when we can expect delivery).

Also, just in case - run the fan test through the menu to ensure the upper fan (that is cooling the extruder) is operational. Moreover, it is recommended to update the firmware to 2.6.5 one.

Best regards,

I went into heating controls and the hotend remains at room temperature. I also checked and the upper fan works fine. I also unplugged the connector for the heater and thermocouple from the PCB board and rebooted the printer and the critical error message came back up, which leans towards the thermocouple being the issue. I will update the printer to the lastest firmware.


thank you for checking what I asked for. Yes, so it seems the heater&thermocouple should be replaced first. If you are having difficulties with finding a spare part - please, let me know via PM. We may be able to find one for you.