Hob flame is yellow or unstable
If after lighting you notice a yellow, lifted or unstable flame the gas burner may not be aligned correctly.
Check for strong draughts near the appliance as this may be affecting the flame of the gas burner.
Turn the corresponding hob control knob to the 0 position.
Allow the gas burner to cool.
Remove the pan supports.
Lift and remove the burner cap.
Make sure there is no liquid in or under the burner cap.
Ensure the crown is securely placed and aligned with the burner cup.
Replace the burner cap.
Re-ignite the desired gas burner and check the flame is not yellow or unstable.