How much does it cost to fix Navien error code E598?

Cost varies. Contact a Gas Safe registered engineer for a quote.

E598 Low

Navien E598 Fault Code

Q: What does the Navien E598 fault code mean?

Your boiler's internal clock has lost its settings, which usually means the system cannot keep time to manage your heating schedule correctly.

The Navien E598 fault code means: your boiler's internal clock has lost its settings, which usually means the system cannot keep time to manage your heating schedule correctly.. It appears on 6 Navien models in our database.

Technical description: Abnormal operation: Panel real time clock

DIY fix possible

Locate the user menu on your boiler's control panel.Navigate to the date and time settings.Manually reset the current date and time to clear the error.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Navien models that show the E598 fault code

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

NCB Repair: £120-200
NCB 28 HE
NCB 35 HE
NCB 40 HE
NCB H
NHB 29

Source

Navien E598 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