BoilerFaultCodesTechnical description
Check if there is 230V~ between motor connections on fan. If yes, replace fan. If no, isolate electrical supply test fan harness continuity; if satisfactory replace printed circuit board.
What causes this fault?
This fault occurs when the boiler's control system attempts to start the fan but detects no movement or electrical response. The most common reasons are a seized fan motor due to age-related wear or a failure on the main circuit board which prevents power from reaching the motor.
This issue is more frequent in autumn when boilers are turned back on after a summer of inactivity, as the fan motor can seize up during long periods of disuse.
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.