004E Medium

Navien 004E Fault Code

The Navien 004E fault code means: your boiler has detected a flame signal when it shouldn't have, but it is currently attempting to clear this error automatically.. It appears on 1 Navien model in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: False-flame error (automatically cleared) displayed on the front panel when flame signal is detected continuously for 3 sec before combustion or during post-purge.
Typical repair cost £120-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Navien models that show the 004E fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Navien 004E fault code information on this page is sourced and cross-checked against the official Navien service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026