High
E109 on Navien NCB

Your boiler has stopped working because the mechanical fan that pushes waste gases outside is not spinning as it should.

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 failure (approximately 0 rpm), loose assembly, or defective connection

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

E012View →E110View →

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