Burners light but go out after a few seconds; furnace retries several times then stops heating.

Safety first: Turn off power and gas before removing the flame sensor.

• Clean flame sensor: Remove the flame sensor and gently polish the metal rod with fine steel wool. Wipe with a clean cloth and reinstall.
• Check ground path: Ensure the burner assembly is tightly fastened to the furnace chassis and that ground wires are secure.
• Inspect burners: Clean rust and debris from burners and ensure flame carries smoothly from burner to burner.
• Replace sensor if needed: If cleaning does not help and the sensor shows signs of damage, install a new Payne-compatible flame sensor.