High
C1 51 on Atag A200

Your boiler is unable to safely vent exhaust gases because the internal fan is not spinning at the required speed.

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 error (speed control is not achieved or is outside of range)

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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