Navien 762 Fault Code
The Navien 762 fault code means: your boiler has detected that the flue pipe responsible for safely venting exhaust gases outside has become loose or disconnected.. It appears on 4 Navien models in our database.
Technical description: The vent installation detector switch will detect if the vent pipe is not fully inserted, and the boiler may not operate.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Navien models that show the 762 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Navien 762 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