BoilerFaultCodesYour boiler has stopped working because the internal fan isn't 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 senses that the fan isn't rotating at the required speed to safely vent exhaust gases out of the flue. The most common reasons are a build-up of dust and debris inside the fan motor, a mechanical seafing of the bearings, or a communication failure 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
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like C1 — no call-out fees, no surprises.
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