Why does my gas burner ignite but the gas goes out when the knob is released?

A faulty thermocouple will cause this fault condition.

The thermocouple uses either gas pressure or electical pressure to ensure the gas valve stays open whilst the end of the thermocouple is in flame. Should the gas go out, the flame dies and the thermocouple cools off and the gas valve is closed.

Without the thermocouple to keep open the gas supply valve, the burner flame will go out as you release the gas valve knob control. The end of the thermocouple is positioned in the flame and held there by a securing bracket, nut or spring washer. A common fault is that they do corrode and fall apart or the thermocouple is not position correctly in the flame because of bracket support failure.

A blocked burner can also cause the fault condition especially when food and debris is spilled onto it.

For most ovens the thermocouples are not an expensive part to buy, ranging from £12.00 to £25.00 however it is a job that should be undertaken by qualified fitters only.