QNAP NAS Error Code 28: How to Fix It

Medium 20-45 minutes Medium Severity Verified June 2026
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Error Code
28
Brand
QNAP
Product Type
nas
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
20-45 minutes
QNAP NAS Error Code 28 indicates that one of the redundant power supply units (PSUs) in your NAS enclosure has been lost or has stopped functioning. Redundant PSUs are designed to keep your NAS running safely if one unit fails, so while your device may still be operational, the protection against a complete power failure is now gone. It is important to address this error promptly to avoid data loss or unplanned downtime if the remaining PSU also fails.
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Tools You'll Need

How to Fix Error Code 28

  1. Check QNAP Notification Center

  2. Inspect the Physical PSU Status LEDs

    Do NOT power off the NAS if your data is actively being used and the remaining PSU is still running. Take note of all indicators before touching anything.

  3. Check Power Connections and Cables

    Use caution when working near energized power supply units. Do not insert fingers or tools into the PSU vents or openings while the unit is plugged in.

  4. Reseat the Faulty Power Supply Unit

    Only reseat the PSU if you have confirmed the other PSU is fully operational and can carry the load. If you must power down, back up critical data first.

  5. Test with a Replacement PSU

    Always use a PSU that is rated and approved for your specific QNAP NAS model. Using an incompatible PSU can damage the enclosure or void your warranty.

  6. Update QNAP Firmware

    Back up your NAS configuration and critical data before performing any firmware update.

  7. Verify Error Is Cleared in System Logs

Parts You May Need

Redundant power supply unit module
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IEC power cable
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UPS (Uninterruptible Power Supply)
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Redundant power supply unit module
Check Price on Amazon
IEC power cable
Check Price on Amazon
UPS (Uninterruptible Power Supply)
Check Price on Amazon
Redundant power supply unit module
Check Price on Amazon
IEC power cable
Check Price on Amazon
UPS (Uninterruptible Power Supply)
Check Price on Amazon
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When to Call a Professional

Contact QNAP support or a certified NAS technician if: the error persists after replacing the PSU with a verified compatible unit; both PSUs are showing faults simultaneously; you suspect a fault in the NAS mainboard's PSU monitoring circuit; your device is under warranty and you do not want to void it by self-servicing; or you are uncomfortable working with powered server hardware. If your NAS is in a production environment with critical business data, engage a professional immediately to minimize downtime risk.

Frequently Asked Questions

Can my QNAP NAS still run with Error Code 28 active?
Yes, in most cases your NAS will continue to operate because the working PSU takes over the full load. However, you have lost redundancy, meaning if the remaining PSU also fails, your NAS will shut down unexpectedly. Fix the issue as soon as possible to restore full protection.
Is Error Code 28 on QNAP NAS a sign of data loss?
Error Code 28 by itself does not cause data loss — it only means one redundant power supply has failed. Your data remains intact as long as the second PSU keeps the NAS running. However, if you ignore the error and the second PSU fails, an unexpected shutdown could corrupt data, especially on volumes with active writes.
How do I find the right replacement PSU for my QNAP NAS?
Check your QNAP NAS model number (printed on the unit's label) and consult the QNAP hardware compatibility list on qnap.com. Search for 'QNAP [your model] replacement power supply' or contact QNAP support directly. Using a PSU not rated for your model can cause hardware damage.
Does QNAP NAS support hot-swap power supply replacement?
Many QNAP enterprise and rackmount NAS models support hot-swappable PSUs, allowing you to replace the failed unit without powering down. However, not all models have this feature. Check your model's hardware user manual or the QNAP product page to confirm before attempting a hot-swap replacement.
Why would a QNAP PSU fail?
Common causes include age and general wear, power surges or unstable input voltage, overheating due to blocked vents or high ambient temperatures, manufacturing defects, and physical damage. Running your NAS through a quality UPS (Uninterruptible Power Supply) can protect PSUs from voltage spikes and extend their lifespan.

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