E.782 High

Navien E.782 Fault Code

Also written as E782 — same fault.

The Navien E.782 fault code means: your boiler's main control unit and the display panel are having trouble 'talking' to each other, which prevents the system from operating correctly.. It appears on 4 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: Panel communication error (Level 1). Displayed when the controller does not respond for more than 60 sec or whenever a panel communication error occurs regardless of the error level.
Typical repair cost £150-300 (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 E.782 fault code

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

Source

Navien E.782 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