High
5.2.19 Error 782 on Navien NCB 40 HE

Your boiler's main internal controller has lost its connection, meaning it cannot receive signals from the display panel to operate your heating and hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Is the wiring from the front panel properly connected to the PCB?

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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