A
bed_thermal
Moderate
Anycubic · FDM 3D Printers
Heated Bed Thermal Runaway - Bed Temperature Outside Safe Range
Quick Answer
Error code BED_THERMAL on your Anycubic FDM 3D Printers means: Heated Bed Thermal Runaway - Bed Temperature Outside Safe Range. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Bed thermistor cable damaged from repeated Y-axis movement
  2. Thermistor detached from the underside of the heated bed
  3. Poor thermal contact between thermistor and bed heater surface
  4. Mainboard bed MOSFET stuck on or delivering inconsistent power
How to Fix It
1
Power off and inspect the bed thermistor cable along its entire routing path for damage
2
Check that the thermistor is securely taped to the underside of the heated bed with Kapton tape
3
Measure bed thermistor resistance (approximately 100K ohms at room temperature)
4
Run bed PID autotune: M303 E-1 S60 C8 then M500 to save
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
Replacement bed thermistor with cable
Kapton tape
Replacement mainboard (if MOSFET issue)
Related Error Codes
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