Technical description
Flame simulation: Gas valve shuts but burner surface continues to glow due to incorrect combustion / Gas valve off but leaking on shut-down - burner flame continuing.
What causes this fault?
This fault occurs when the boiler's sensors detect a flame or intense heat inside the unit at a time when the gas should be completely shut off. The most common reason is a gas valve that is failing to close fully, allowing a small amount of fuel to continue burning, or a faulty sensor that is incorrectly reporting heat to the main control board.
Engineer required
This is a emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.