High
4 flashes red on Main Insul 7

Your boiler is having trouble breathing because a part responsible for moving air and fumes is not working correctly, which has caused it to shut down for safety.

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 fault (Fan calibration error, Fan failure)

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

E04View →E110View →

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