Solve the Navien Tankless Water Heater Error Code

Encountering errors with your tankless water heater can be frustrating. Navien tankless water heaters, known for their efficiency and reliability, can still face occasional issues.

This guide comprehensively looks at common Navien tankless water heater error codes, practical solutions, and expert insights.

Read also: What Causes Water Heater Igniter Won’t Spark

Understanding Navien Tankless Water Heater Error Codes

Error Code E001: Water Boiling in the Heat Exchanger

Issue: Indicates water boiling inside the heat exchanger.

Steps to Troubleshoot:

1. Clean the Water Inlet Strainer: Remove any debris that may be blocking water flow.
2. Check Automatic Flow: Ensure the automatic flow control is working correctly.
3. Inspect and Clean the Heat Exchanger: Use a cleaning solution to remove any scale buildup.

Expert Insight: Regular maintenance, such as descaling the heat exchanger annually, can prevent this issue.

Error Code E002: Low Water Pressure

Issue: Indicates low water pressure in the system.

Steps to Troubleshoot:

1. Wait for Water Supply Restoration: Ensure that the water supply is consistent.
2. Perform Automatic Reset: Reset the system if necessary.

Expert Insight: Low water pressure can often be linked to issues with the municipal water supply or internal plumbing problems. One user discovered that a partially closed valve was causing the issue.

Error Code E003: Ignition Failure

Issue: The unit fails to ignite the burner.

Steps to Troubleshoot:

1. Check Gas Supply: Ensure the main gas supply is on and provides adequate pressure.
2. Inspect Electrical Power: Verify that the power supply to the heater is uninterrupted.
3. Check Igniter Spark: Look for a spark in the igniter and replace it if it is faulty.

Error Code E004: False Flame Detection

Issue: The system detects a flame when there is none.

Steps to Troubleshoot:

1. Ensure Ground Wire Connection: Verify that the ground wire is securely connected.
2. Check Igniter for Spark: Inspect and ensure the igniter is working correctly.

Expert Insight: Electrical interference can often cause false flame detection. Using a surge protector can help mitigate this risk.

Error Code E007: Thermistor Open (Hot Water Outlet)

Issue: The hot water outlet thermistor is open.

Steps to Troubleshoot:

1. Check Thermistor: Inspect the thermistor for damage or disconnection.
2. Replace if Necessary: If the thermistor is faulty, replace it.

Error Code E008: Thermistor Short (Hot Water Outlet)

Issue: The hot water outlet thermistor is shorted.

Steps to Troubleshoot:

1. Inspect and Replace Thermistor: Check for shorts in the thermistor and replace it if needed.

Expert Insight: Short circuits in thermistors often occur due to moisture ingress. Proper sealing during installation can prevent this issue.

Error Code E009: Abnormal Fan Motor Activity

Issue: The fan motor is not operating correctly.

Steps to Troubleshoot:

1. Clean Air Filter and Fan Motor: Remove dust and debris from the air filter and fan motor.
2. Check Connections: Ensure all wiring connections are secure.

Error Code E010: Abnormal Air Pressure

Issue: There is abnormal air pressure in the system.

Steps to Troubleshoot:

1. Inspect Vent Pipe: Check for obstructions in the vent pipe.
2. Clean Air Filter: Ensure the air filter is clean and unobstructed.

Expert Insight: Proper ventilation is crucial for tankless water heaters. An installer found that inadequate venting during installation led to this error in several units.

Error Code E011: High Water Pressure

Issue: The system detects high water pressure.

Steps to Troubleshoot:

1. Check Water Pressure Sensor: Inspect the sensor for accuracy.
2. Perform Automatic Reset: Reset the system to clear the error.

Error Code E015: Abnormal Control Board Function

Issue: There are abnormal functions in the control board.

Steps to Troubleshoot:

1. Check Power Supply: Ensure the power supply is stable and sufficient.
2. Inspect GFI: Verify the Ground Fault Interrupter (GFI) is functioning properly.

Expert Insight: Control board issues often stem from electrical surges. Using surge protectors and ensuring a stable power supply can mitigate these problems.

Error Code E016: Overheating in the Heat Exchanger

Issue: The heat exchanger is overheating.

Steps to Troubleshoot:

1. Turn Off Water Heater: Allow the unit to cool for at least 30 minutes.
2. Clean Strainer Water Inlet: Ensure the inlet strainer is free of debris.
3. Check Automatic Flow Adjustment Valve: Inspect and adjust the valve if needed.
4. Clean Heat Exchanger: Use a cleaning solution to descale the heat exchanger.

Error Code E021: Thermistor Open (Cold Water Inlet)

Issue: The cold water inlet thermistor is open.

Steps to Troubleshoot:

1. Inspect Thermistor: Check for any disconnection or damage.
2. Replace if Necessary: If the thermistor is faulty, replace it.

Expert Insight: Thermistor issues often result from improper handling during installation. Ensuring careful installation can prevent these errors.

Conclusion

Navien tankless water heaters are reliable and efficient, but like any complex system, they require proper maintenance and timely troubleshooting. Understanding these common Navien tankless water heater error codes and their solutions can help ensure your water heater operates smoothly.

Contacting a professional technician is advisable for those experiencing persistent issues or complex problems. Regular maintenance, including descaling and inspecting components, can prevent many common errors and extend the lifespan of your tankless water heater.