BoilerFaultCodesYour boiler's fan is not spinning fast enough to safely start the burner, causing the system to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Burner in fault state. Fan speed too low at burner start. Cause: Check the fan, check the fan cables and supply, check the fan control. Press E.
What causes this fault?
This fault occurs when the boiler's internal computer tries to start the heating process but detects that the fan isn't reaching the necessary speed to clear out exhaust gases. The most common reasons are a build-up of debris causing the fan to stick, a failure in the fan's motor, or a loose electrical connection between the fan and the main control board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F9 — no call-out fees, no surprises.
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Viessmann Vitodens 333 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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