High Lockout
C6 on Worcester Bosch CDi Classic

Your boiler has stopped working because the internal fan, which safely removes waste gases, is not spinning fast enough.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Fan speed too low – the fan lead and connector need checking and may need replacing.

What causes this fault?

This fault occurs when the boiler's control board detects that the fan is not spinning at the required speed to safely expel exhaust fumes. The most common reasons are a build-up of dust and debris within the fan motor bearings or an electrical failure in the wiring that connects the fan to the main power supply.

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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Related fault codes

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