How much does it cost to fix Navien error code E517?

Typical repair cost for the Navien E517 fault is £120-200 including labour.

E517 High

Navien E517 Fault Code

Q: What does the Navien E517 fault code mean?

Your boiler’s internal computer has identified an error in how its internal configuration switches are set, meaning it cannot operate safely until these are corrected.

The Navien E517 fault code means: your boiler’s internal computer has identified an error in how its internal configuration switches are set, meaning it cannot operate safely until these are corrected.. It appears on 7 Navien models in our database.

Technical description: Abnormal operation: DIP switch setting (PCB)

Typical repair cost £120-200 (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 E517 fault code

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

LCB700 Repair: £120-200
NCB Repair: £150-300
NCB 28 HE Repair: £120-250
NCB 35 HE Repair: £120-250
NCB 40 HE Repair: £120-250
NCB CE Repair: £120-200
NCB H Repair: £120-250

Source

Navien E517 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