Low
E598 on Navien NCB

Your boiler's internal clock has lost its settings, which is likely preventing the system from running on its programmed schedule.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Abnormal operation: Panel real time clock

From this model's manual
Verified against the Navien Ncb installation & service manual, page 74.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check the time and date settings on the boiler control panelManually reset the clock to the current timePress the reset button to clear the fault codeCheck if the scheduled timer programs need to be re-entered

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