Gas burner goes out when knob is released on Fagor gas cooktop.

Safety first: Work with gas components only if you are competent. Shut off gas supply before removing burners or valves.

• Hold knob longer: When lighting, press and hold the knob for 5–10 seconds to allow the thermocouple to heat fully.
• Check flame contact: Ensure the flame directly touches the thermocouple tip. Clean the burner and adjust cap alignment so the flame surrounds the sensor.
• Inspect thermocouple: If the flame is correct but still goes out, the thermocouple may be worn. Replace the thermocouple for that burner.
• Gas valve check: If a new thermocouple does not solve the issue, the safety gas valve magnet may be defective and should be replaced by a technician.