E30 High

Navien E30 Fault Code

The Navien E30 fault code means: your boiler has detected an issue with the sensor that monitors the temperature of the gases leaving your flue, meaning the boiler has stopped working to prevent overheating.. It appears on 6 Navien models in our database.

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: Exhaust gas temperature sensor error
Typical repair cost £150-250 (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 E30 fault code

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

Source

Navien E30 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 27 April 2026