Technical description
Electronic fault in flame system (non–plausible flame signal) | Cause: Electronic fault
What causes this fault?
This fault occurs when the boiler's internal computer receives a signal that a flame is present even though the gas valve is closed. The most common reason is a malfunction in the printed circuit board (PCB) or a damaged sensing electrode that is sending a false electrical signal. Essentially, the boiler enters a fail-safe mode because it sees a 'ghost flame' and shuts down to ensure your safety.
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.