Creality error 2507 (Not Heating as Expected) appears on K1 and K1 Max printers running firmware versions below 1.3.1.x. It is a catch-all thermal error raised whenever the hotend or heated bed is commanded to heat but temperature does not rise within the expected time window. On firmware 1.3.1 and later, this error was replaced by the more specific error 2564 (nozzle not heating) and error 2565 (heat bed not heating).

What the Error Means

Error 2507 indicates that a powered heater — either the hotend heater cartridge or the bed heater — is not producing the expected temperature rise. The firmware monitors the rate of temperature increase after commanding a heater on, and if the measured temperature remains flat or rises too slowly, it concludes that the heater circuit has failed and triggers a thermal protection shutdown to prevent fire risk. Because firmware below 1.3.1 did not distinguish between the two heater circuits, error 2507 applies to both. Common causes are an open-circuit heater cartridge, a disconnected thermistor (which causes the firmware to see no temperature rise even if the heater is working), broken wiring at the hotend or bed connector, or a cracked ceramic heat block that has lost thermal contact.

Step-by-Step Fix

1. Restart the printer and heat the hotend to 240°C and the bed to 90°C individually, one at a time. Observe which component triggers the error — this isolates the fault to hotend or bed.
2. If the hotend triggers the error, follow the diagnostic from error 2564: reseat the heater cartridge and thermistor connectors at the hotend board, inspect wiring for breaks near the heater block, and use a multimeter to check heater cartridge resistance (10–20 ohms expected) and thermistor resistance (approximately 100,000 ohms at 25°C).
3. If the heat bed triggers the error, follow the diagnostic from error 2565: reseat the bed power connector at the mainboard, inspect the bed wiring harness for damaged insulation along the Y-axis path, and check bed heater resistance (1–3 ohms expected for K1-series beds).
4. Inspect the ceramic heat block on the hotend for visible cracks. A cracked block loses thermal efficiency and may never reach target temperature. Replace a cracked heat block.
5. Update the printer firmware to version 1.3.1 or later via Settings → About → Firmware Update. The updated firmware separates error 2507 into specific codes 2564 and 2565, giving you a clearer diagnosis on the next occurrence.
6. If you cannot isolate the fault to hotend or bed, replace the heater cartridge and thermistor as a matched set, as these are the most common hardware failures in this error family.

Parts Required

• Heater cartridge (24V, K1/K1 Max compatible) — if hotend is the fault
• NTC100K thermistor (K1/K1 Max compatible) — if hotend thermistor is faulty
• Ceramic heat block — only if cracked
• Multimeter

Contact Creality support if error 2507 persists after replacing the heater cartridge and thermistor with confirmed-good parts.

Frequently asked questions

What does Creality 2507 mean?

Creality error 2507 (Not Heating as Expected) appears on K1 and K1 Max printers running firmware versions below 1.3.1.x. It is a catch-all thermal error raised whenever the hotend or heated bed is commanded to heat but temperature does not rise within the expected time window. On firmware 1.3.1 and later, this error was replaced by the more specific error 2564 (nozzle not heating) and error 2565 (heat bed not heating).

How do I fix Creality 2507?

Creality K1/K1 Max error 2507 is a thermal runaway catch-all on older firmware. Update to 1.3.1+ for a specific code, or isolate the hotend vs. heat bed heater.