BoilerFaultCodesNavien E030 Fault Code
The Navien E030 fault code means: your boiler is detecting an issue with water flow or heat levels, which could mean dangerous air or gas is trapped inside where it shouldn't be.. It appears on 6 Navien models in our database.
Technical description: Primary Heat Exchanger/Secondary Heat Exchanger/DHW Heat Exchanger: Exhaust gas leaks; Overheating of water causes bubbling noises; Low temperature water in the heat exchanger
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 E030 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Navien E030 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