BoilerFaultCodesTechnical description
Flame simulation error
What causes this fault?
This fault occurs when the boiler's internal sensor detects an electrical signal suggesting a flame is present even though the gas valve is closed. The most common reasons are a moisture-damaged ignition lead or a faulty electrode that is sending a 'false positive' signal back to the main control board. If the sensor is clear, it usually indicates that the circuit board itself is misinterpreting electrical noise as a flame.
This fault can be more frequent during periods of high humidity or heavy rain, as moisture entering the casing can interfere with the sensitive electrical signals of the ionisation circuit.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.