Navien Error 598-00: What Is Known and What to Do
On this page (5 sections)
The Short Answer: Error 598 isn’t listed in the error-code table of Navien’s NPE-2 owner’s manual, so we can’t confirm its meaning from Navien’s documentation. It is commonly described as an abnormal real-time clock (RTC), meaning the control’s clock or front-panel electronics. If hot water still works, it isn’t an emergency. Record the code, reset once, and confirm the meaning with Navien technical support before anyone replaces parts.
What we could and couldn’t confirm
The NPE-2 user’s manual (December 2020 edition) lists codes from E003 through E788. The nearby electronics codes it does include are E593 (front panel key), E594 (EEPROM) and E615 (input and memory). Code 598 isn’t in that table. Newer firmware, other Navien product lines, and Navien’s service literature may include codes that owner manuals don’t.
Many reports describe 598 as a real-time clock fault. That would make it a problem with timekeeping, which Navien heaters use for recirculation schedules and fault history, rather than with heating. We haven’t found that definition in a Navien document. The -00 after the number is a sub-code and may matter to Navien when it diagnoses the fault.
How urgent is it?
| Situation | What it suggests | What to do |
|---|---|---|
| 598 shows, hot water works normally | Electronics or clock fault that isn’t stopping heating | Record it, reset once, contact Navien or your installer |
| 598 shows and recirculation schedules no longer run on time | Consistent with a clock problem | Same; reset the schedule after the fault is cleared |
| 598 plus no hot water | Possibly a second fault | Look for other codes; see Navien won’t turn on |
| 598 appeared after a power outage or surge | Electronics disturbed by the power event | Reset once; see Navien after a power outage |
What you can do
- Photograph the display, including the
-00, and note the model from the rating plate (for example NPE-240A2). - Reset once. On NPE-2 models, Navien’s manual says to press the Back button. If that doesn’t clear it, turning the heater off and on at its power supply once is a reasonable next step.
- Check the date and time if your model or the NaviLink app shows them. Re-enter them if they’re wrong.
- Note whether it comes back and how often: immediately, daily, or after power interruptions.
- Contact Navien technical support (the number in the NPE-2 manual is 1-800-519-8794) or your installer with the model, serial number and code. Ask what 598 means on your model and firmware.
Avoid repeated factory resets. They can wipe recirculation, cascade and installation settings that the installer chose for your system.
What the technician will check
A Navien-trained technician can read the full fault history, confirm what 598 means for your model and firmware, and check the front panel, its connection to the main control board, and the power supply quality. If a part is needed, it is most likely an electronics component such as the front panel or control board, not a gas or water part. After any board or panel replacement, the technician re-enters the installation settings.
Frequently Asked Questions
Q: Can I keep using the heater with 598 on the display? A: If it’s heating normally and there are no other codes, leaks or odors, it’s generally reasonable to keep using it while you arrange to have the code confirmed. Stop if other codes appear or the heater behaves differently.
Q: Is 598 covered by warranty? A: Electronics parts are often covered for a set period from installation. Navien’s warranty depends on the model, application and installation date, so have the serial number ready when you contact them.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Navien NPE-2 Series user's information manual (opens in a new tab)Navien NPE-A2 and NPE-S2 owner error table and reset procedure; 598 is not listed in this edition.
- Navien: manuals and product documents (opens in a new tab)Model-specific owner information; service manuals are intended for qualified professionals.
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