Low
E598 on Navien NCB500

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

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

Shared across the NCB500 range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
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

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.

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All 52 fault codes on the NCB500

Seeing a different code? Every code this model can display, in one place.

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