A
thermal_runaway
Moderate
Anycubic · FDM 3D Printers
Hotend Temperature Exceeded Safety Limits
Quick Answer
Error code THERMAL_RUNAWAY on your Anycubic FDM 3D Printers means: Hotend Temperature Exceeded Safety Limits. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Thermistor wiring damaged or making intermittent contact
  2. Heater cartridge loose in the heat block causing temperature oscillation
  3. Silicone sock fell off the heat block exposing it to cooling airflow
  4. PID tuning values not calibrated for the current hotend configuration
How to Fix It
1
Power off the printer immediately and allow the hotend to cool
2
Inspect the thermistor wire from the heat block all the way to the mainboard for damage
3
Verify the heater cartridge is firmly seated in the heat block with the set screw tightened
4
Run PID autotune via a serial terminal: M303 E0 S200 C8 then M500 to save
5
Replace the silicone sock if it is missing or degraded
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
NTC 100K thermistor
Silicone sock for heat block
24V 40W heater cartridge
Related Error Codes
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