BoilerFaultCodesTechnical description
fan pre-run
What causes this fault?
This fault occurs when the boiler's control system is waiting for confirmation that the fan is spinning at the correct speed to safely clear out gases before ignition. The most common reason is that the fan has become worn or blocked, or the circuit board is failing to receive the electrical signal required to move to the next step of the starting process.
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.
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