High
E109 on Navien NCB300

Your boiler has stopped working because the internal fan that pushes out harmful exhaust gases is not running properly.

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.

What the manual says

Manufacturer manual

Fan Motor fault

From this model's manual
Verified against the Navien/Navien Ncb300 Combi Service Manual30k 250328 Pdf installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

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

E108View →E110View →

All 56 fault codes on the NCB300

Seeing a different code? Every code this model can display, in one place.

001003004004E012012E016016E030030E031046047109109E205302407515517593594615740782E001E003E004E012E016E030E031E046E047E110E205E218E302E351E352E353E407E421E439E515E517E593E594E598E615E740E782E783E787E788

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