Navien Error Code 515-09 Abnormal PCB - Issue Fixed

Tech Feb 7, 2025 36 Add to Reading List

If your Navien tankless water heater or boiler is displaying the error code 515-09, it’s important to understand what the error means and how to address it. This error code indicates an "Abnormal PCB," pointing to an issue with the unit’s Printed Circuit Board (PCB). The PCB plays a vital role in controlling the functions of your Navien appliance, and a malfunction can significantly affect the unit’s performance. This article will explain what the error means, what happens when it occurs, and how to resolve the issue.

Understanding Navien Error Code 515-09

The Navien Error Code 515-09 is a diagnostic message indicating that there is a malfunction with the PCB inside your Navien tankless water heater or combi boiler. The PCB is a crucial component in the system, as it manages many functions and processes. When the error code appears, it typically suggests that there’s an issue with this key part, potentially leading to disruptions in the unit’s operation. If left unchecked, the problem can cause a complete shutdown or lead to further issues with the appliance’s performance.

What Happens When Error Code 515-09 Is Triggered?

When the Navien Error Code 515-09 Abnormal PCB appears, the unit will usually shut down automatically as a protective measure. This shutdown is designed to prevent further damage and ensure that the unit does not continue running under faulty conditions. The following are some of the symptoms and consequences you may experience:

No Hot Water: The most immediate and noticeable issue is the lack of hot water. Your water heater or combi boiler will fail to heat water, which can make it difficult to carry out essential tasks like taking showers, washing dishes, or doing laundry.
System Shutdown: As part of the safety mechanism, the unit will shut itself down to avoid further complications. This is a built-in feature designed to protect the system from operating under suboptimal conditions.
Error Code Display: Once the error is triggered, the control panel on your Navien unit will display the error code 515-09. This is a helpful diagnostic tool that both homeowners and technicians can use to identify the problem quickly.
Lockout Mode: In some instances, the unit may enter a lockout mode. This means that the system will remain inoperable until the error is resolved and the unit is manually reset.
Gas Odor (Rare): In rare cases, a faint gas smell may accompany the PCB malfunction. This is a safety feature designed to alert you to any potential gas-related issues that could arise from the problem.

How to Resolve Navien Error Code 515-09

The 515-09 error code is related to a problem with the PCB, but there are a few steps you can take to troubleshoot and potentially resolve the issue. Here’s what you can do:

Step 1 – Check the Gas Supply

Ensure that the gas supply to the unit is open and functioning properly. If the gas valve is closed, open it. Check that the gas pressure is within the recommended range. Adequate gas flow is necessary for the unit to operate efficiently and correctly.

Step 2 – Inspect the Flame Rod

The flame rod plays a vital role in the ignition process. If it’s dirty or corroded, it may prevent the system from igniting properly. Clean the flame rod if needed and ensure it is correctly positioned, making good electrical contact.

Step 3 – Examine the Venting System

A blocked venting system can negatively impact your unit’s performance. Check for any debris or obstructions, such as animal nests, that might be blocking the airflow. Clear any blockages to restore proper ventilation, which is essential for safe and efficient operation.

Step 4 – Inspect Ignition Components

The ignition components, including the igniter and gas valve, must be in good working condition for the unit to function properly. If you notice any issues with these parts, replace them to avoid further malfunctioning.

Step 5 – Examine Wiring and Connections

Check the internal wiring and connections for any loose, damaged, or corroded parts. Damaged or faulty wiring can prevent the unit from receiving the necessary electrical power. Repair or replace any damaged wiring as needed.

Step 6 – Reset the Unit

After addressing the issues above, try resetting the unit. In many cases, a simple reset will clear the error code if the problem has been fixed. If the error persists, further investigation may be required.

By following these troubleshooting steps, you may be able to resolve the 515-09 error code and restore your Navien water heater or combi boiler to full functionality.

Additional Tips for Troubleshooting Navien Error Code 515-09

To make the troubleshooting process easier and safer, consider these additional tips:

Prioritize Safety: When dealing with gas and electrical components, safety should always be the top priority. If you’re uncertain about handling these parts, it’s best to contact a certified Navien technician who can perform the repairs safely.
Schedule Regular Maintenance: Regular maintenance can help prevent issues like the 515-09 error code from occurring. This includes tasks such as cleaning filters, inspecting for debris, and identifying potential problems early. Regular upkeep can extend the lifespan of your unit and ensure that it performs optimally.
Consult the User Manual: Always refer to the user manual of your Navien unit for specific troubleshooting steps. The manufacturer’s guidelines will provide the most accurate and reliable information for resolving error codes.
Seek Professional Help: If you’re unable to resolve the issue or if the error code persists, don’t hesitate to call in a professional. A qualified Navien technician can help you diagnose the problem and perform any necessary repairs to restore your unit to proper working order.

Other Common Navien Error Codes

In addition to the 515-09 error, there are several other error codes that may appear on your Navien unit. Here are a few common ones and how to address them:

E001 – Ignition Failure: This error is often caused by a dirty or faulty flame rod, insufficient air supply, or a malfunctioning ignition electrode. To resolve it, check the gas supply, clean the flame rod, ensure proper ventilation, and inspect the ignition components.
E003 – Flame Failure: This error occurs when the system fails to maintain a stable flame. It could be caused by issues with the gas supply, the flame rod, or the exhaust vent. Check the gas supply, clean the flame rod, and inspect the vent for blockages.
E010 – Flow Sensor Issue: The flow sensor may be defective or blocked, preventing the unit from functioning correctly. Inspect the sensor for damage, check the water flow for obstructions, and ensure the wiring is intact.
E016 – Overheating: Overheating can occur due to blocked vents or poor ventilation. Clear any obstructions from the vents and ensure the unit has ample space around it for proper airflow.
E030 – Air Pressure Sensor Error: This error is typically caused by issues with the air pressure sensor or improper venting. Check the sensor and make sure the unit is properly ventilated.
E038 – Circulation Pump Error: This error indicates a problem with the circulation pump, possibly due to malfunctioning parts or damaged wiring. Inspect the pump, check its connections, and ensure it’s functioning properly.

If you encounter these or other error codes, addressing them promptly can prevent further damage and ensure your Navien unit operates smoothly. For complex issues or if you’re unable to resolve the error, it’s always best to consult a professional technician.

Conclusion: Fixing Navien Error Code 515-09

The Navien Error Code 515-09 indicates a malfunction with the PCB in your water heater or combi boiler. If not addressed, this error can result in a loss of hot water and even cause safety hazards. Fortunately, by following the troubleshooting steps outlined above—such as checking the gas supply, inspecting components, and resetting the unit—you can often resolve the issue and restore your Navien unit to full functionality.

Frequently Asked Questions

How do you check Navien error codes?
You can check error codes by accessing the Diagnostic Menu on your unit’s control panel. The error code will be displayed for reference.
How do you clear Navien error codes?
To clear an error, first address the underlying issue, then turn off the power, wait for a few minutes, and restart the unit. If the error persists, further troubleshooting is needed.
Is Error Code 515-09 common?
While not very common, this error can occur due to issues such as sensor malfunctions or water flow problems. Regular maintenance can help reduce the chances of encountering this error.
Can I continue using my Navien unit with Error Code 515-09?
It is not advisable to continue using your Navien unit with this error code active, as it could lead to further damage or higher repair costs.
Is this error covered by Navien’s warranty?
Whether the 515-09 error is covered under warranty depends on your specific agreement. Review your warranty documentation to determine if repairs related to this error are covered.

By staying proactive with maintenance and addressing error codes promptly, you can help your Navien unit run efficiently. If you’re unsure or the issue persists, always consult a professional technician to ensure a safe and effective resolution.