BoilerFaultCodesYour boiler has stopped working because the internal fan is not spinning fast enough to safely clear away exhaust fumes.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fan speed too low
What causes this fault?
This fault occurs when the boiler's control system detects that the fan is not spinning at the correct speed to safely expel waste gases through the flue. The most common reasons include a buildup of dust and debris within the fan motor, a loose electrical connection, or a failing control board that is unable to send the correct power signal to the fan.
This fault is slightly more common in winter when the boiler works harder and the fan runs for longer periods, which can cause aging motor bearings to seize or fail.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like C1 — no call-out fees, no surprises.
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