Gas burner ignites but goes out when the knob is released on a Grundig gas hob.

Safety first: Work in a well‑ventilated area. If the burner repeatedly goes out, avoid continuous attempts to light it.

• Hold knob longer: Press and hold the control knob fully in for 5–10 seconds after ignition to allow the thermocouple to heat.
• Clean burner: Remove and clean the burner cap and head so the flame properly surrounds the thermocouple tip.
• Check thermocouple position: Ensure the small metal rod (thermocouple) is close to the flame; gently adjust if bent, but do not force.

If the flame still goes out when releasing the knob, the thermocouple or gas valve for that burner likely needs replacement by a qualified gas technician.