BoilerFaultCodesTechnical description
Flame simulation.
What causes this fault?
This fault occurs when the boiler's sensors detect an electrical current and assume a flame is present before the gas has even been ignited. This is usually caused by a faulty ionisation electrode sending a false signal or moisture and carbon build-up creating an electrical 'leak' back to the control board. For safety, the system refuses to start the ignition sequence to prevent gas from entering a chamber it believes is already lit.
This fault is more common during periods of high humidity or heavy rainfall, as moisture ingress can affect the electrical sensitivity of the ignition components.
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.