Navien Tankless Water Heater Problems: Error Codes Explained

As a seasoned plumber with 30 years in the field, I’ve seen my fair share of tankless water heater issues. Over the years, one brand that has repeatedly popped up on my radar is Navien. Don’t get me wrong – Navien tankless water heaters are generally reliable and efficient. However, like any complex appliance, they’re not immune to problems.

In fact, I’ve encountered nearly every issue you can think of with Navien tankless water heaters, from minor glitches to major malfunctions that left homeowners without hot water for days.

In this blog post, I’ll share my experience with Navien tankless water heater problems, including the most common error codes, their causes, and how to fix them. Whether you’re a homeowner who owns a Navien tankless water heater or a plumber who frequently deals with these appliances, this post will provide valuable insights into troubleshooting common Navien tankless water heater problems.

Navien Tankless Water Heater Error Codes & Solutions

Error codes are among the most frustrating issues with Navien tankless water heaters. These codes indicate a problem with the system that needs to be addressed, but it can be challenging to diagnose the issue without a clear explanation.

Here are the most common Navien error code problems and what they mean:

Error Code E001 – Water Boiling in Heat Exchanger

Navien tankless water heater error code E001 indicates water boiling in the heat exchanger. When this error code appears, the water heater may shut down entirely, leaving you without hot water. The error code is usually displayed on the unit’s control panel, and it may also cause the unit’s LED lights to blink.

Troubleshoot & Fix E001

Error Code E002: Low Water Pressure

The Navien tankless water heater error code E002 signals a low water pressure issue. This error code is usually displayed when the water pressure in the system falls below the recommended minimum level. This can happen for several reasons, including:

• Clogged or restricted water supply lines: If blocked or restricted, it can cause a drop in water pressure, resulting in the E002 error code.
• Faulty water pressure regulator: If the water pressure regulator is not functioning correctly, it can cause the water pressure to drop, resulting in the E002 error code.
• Leaking pipes: A leak in the water supply pipes can cause a drop in water pressure, resulting in the E002 error code.

Solution:

1. Check the water pressure: The first step in resolving the E002 error code is to check the water pressure. If it is too low, you may need to adjust the water pressure to ensure it falls within the recommended range.
2. Check the water supply lines: If the water pressure is within the recommended range, check whether it is clogged or restricted. If they are, clear them to restore water pressure to the system.
3. Check the water pressure regulator: If the water supply lines are clear, check the water pressure regulator to see if it functions correctly. If it is not, you may need to replace it.
4. Check for leaks in the water supply pipes: If the water pressure regulator is in good working condition, check for leaks in the water supply pipes. If there is a leak, repair it to restore water pressure to the system.

Error Code E003: Ignition Failure

The Navien tankless water heater error code E003 signals an ignition failure. This error code typically occurs when the heating system is unable to ignite the burners, resulting in a lack of hot water. This can be caused by several factors, including:

• Insufficient gas supply: If not enough gas is supplied to the system, the burners will not ignite, resulting in the E003 error code.
• Clogged or dirty burners: If the burners are clogged or dirty, they may not ignite properly, resulting in the E003 error code.
• Faulty igniter: If the igniter is not functioning correctly, it may not be able to ignite the burners, resulting in the E003 error code.

Solution:

• Check the gas supply: The first step in resolving the E003 error code is to check the gas supply. Ensure enough gas is supplied to the system; if not, call your gas supplier to resolve the issue.
• Clean or replace the burners: If the gas supply is adequate, check them to see if they are clogged or dirty. If they are, clean or replace them to ensure they ignite correctly.
• Replace the igniter: Check the igniter to see if the burners are clean and functioning properly. If it is not working correctly, you may need to replace it.

Troubleshoot and Fix 003

Error Code: E004 False Flame Detection

The Navien tankless water heater error code E004 signals a false flame detection. This error code typically occurs when the heating system detects a flame even though no flame is present. This can be caused by several factors, including:

• Faulty flame sensor: If the flame sensor is not functioning correctly, it may detect a flame even when there is none, resulting in the E004 error code.
• Loose wiring: If the wiring connecting the flame sensor to the control panel is loose, it may cause the flame sensor to detect a false flame, resulting in the E004 error code.
• Gas supply issue: If there is an issue with the gas supply, it may cause the flame sensor to detect a false flame, resulting in the E004 error code.

Solution:

1. Check the flame sensor: The first step in resolving the E004 error code is to check the flame sensor. Ensure that it is functioning correctly and that there are no issues with the wiring connecting it to the control panel.
2. Check the gas supply: If the flame sensor and wiring function correctly, check the gas supply. Ensure enough gas is supplied to the system; if not, call your gas supplier to resolve the issue.

Error Code E007: Hot Water Outlet Thermistor Open

The Navien tankless water heater error code E007 signals a problem with the hot water outlet thermistor. The thermistor is a component that measures the temperature of the hot water leaving the heater. This error code typically occurs when the thermistor cannot correctly calculate the temperature of the hot water, failing to regulate the heating system.

Solution:

1. Check the thermistor: The first step in resolving the E007 error code is to check the hot water outlet thermistor. Ensure that it is properly connected to the control panel and that there are no issues with the wiring.
2. Check the hot water outlet temperature: If the thermistor and wiring appear to be functioning correctly, check the temperature of the hot water outlet. If the temperature is incorrect, there may be an issue with the heating system.

Error Code E009: Abnormal Fan Activity

The Navien tankless water heater error code E009 signals a problem with the fan activity within the unit. The fan is responsible for circulating air within the heater and regulating the temperature, so when the fan is not functioning correctly, it can result in a range of issues and potentially even damage to the unit.

Solution:

1. Check the fan: The first step in resolving the E009 error code is to check the fan. Look for any signs of damage or wear and tear, such as blade cracks or breaks.
2. Check the wiring: If the fan appears to be in good condition, check the wiring for any signs of damage or issues. Make sure that all connections are tight and secure.
3. Clean the fan: If the fan appears to be in good condition and the wiring is secure, the fan may be simply dirty. Clean the fan and surrounding area to ensure that it is functioning correctly.

Error Code E010: Abnormal Air Pressure

The Navien tankless water heater error code E010 signals an issue with the air pressure within the unit. The air pressure is responsible for maintaining the balance and efficiency of the heating process, so any issues with the air pressure can significantly impact the unit’s performance.

Solution:

If you are experiencing the E010 error code on your Navien tankless water heater, there are a few steps you can take to troubleshoot the issue:

1. Check the air intake: The first step in resolving the E010 error code is to check the air intake. Look for any signs of blockage or restriction, such as dirt, debris, or other foreign objects.
2. Check the air filter: The air filter removes impurities from the air before entering the unit. If the air filter is dirty or clogged, it can restrict air flow, leading to air pressure issues. Replace the air filter if necessary.
3. Check the air ducts: The air ducts within the unit are responsible for directing airflow. If the ducts are damaged or restricted, it can lead to issues with air pressure.

Error Code E011: High Water Pressure

If you’re experiencing the error code E011 on your Navien tankless water heater, the unit detects high water pressure in the system. High water pressure can cause issues and damage the unit if left unaddressed. In this article, we’ll go over the steps you can take to troubleshoot and resolve the E011 error code on your Navien tankless water heater.

Step 1: Check the Incoming Water Pressure

The first step in troubleshooting the E011 error code is to check the incoming water pressure to your unit. The incoming water pressure should be between 30 and 80 PSI. If the water pressure exceeds 80 PSI, you must install a pressure-reducing valve to bring the pressure down to the proper level.

Step 2: Check the Water Pressure Regulator

If the incoming water pressure is within the recommended range, the next step is to check the water pressure regulator on your Navien tankless water heater. This is a small valve that regulates the water pressure entering the unit. If the regulator is clogged or damaged, it can cause the water pressure to be too high, triggering the E011 error code. To check the regulator, remove it from the unit and clean or replace it if necessary.

Step 3: Check the Water Pressure Relief Valve

The water pressure relief valve is another component that can cause high pressure in your Navien tankless water heater. If the relief valve is stuck open, it can allow water to flow into the unit at a higher pressure than what it is designed to handle. To check the relief valve, remove it from the unit and clean or replace it if necessary.

Step 4: Check the Inlet and Outlet Pipes

Finally, suppose you’ve checked the incoming water pressure, the water pressure regulator, and the water pressure relief valve, and you’re still experiencing the E011 error code. In that case, it’s time to check the inlet and outlet pipes on your Navien tankless water heater. Ensure that the pipes are securely connected and that there are no leaks or clogs in the system.

Error Code E012: Flame Loss

Encountering the error code E012 means your unit detected a flame loss. This issue can prevent your water heater from functioning properly, which can be a major inconvenience. Fortunately, there are several steps you can take to troubleshoot and resolve the issue.

Step 1: Check the Gas Supply

The first step in resolving a flame loss error is to check the gas supply to your water heater. Ensure that the gas supply valve is open and that your unit has adequate gas flow. If the gas supply is turned off, turn it on and check for any leaks in the gas line.

Step 2: Inspect the Ignition System

If the gas supply is adequate, inspecting the ignition system is next. Check the igniter for any signs of damage or wear. If the igniter is damaged, replace it. If the igniter is not damaged, inspect the wiring connections and check for any loose or disconnected wires.

Step 3: Check the Burner Assembly

If the ignition system functions correctly, the next step is to check the burner assembly. Ensure the burner assembly is debris-free and the air intake is clear. If the burner assembly is dirty, clean it and check for any damage. If the burner assembly is damaged, replace it.

Step 4: Check the Thermocouple

If the burner assembly is functioning properly, the next step is to check the thermocouple. The thermocouple detects a flame’s presence and maintains the unit’s gas flow. If the thermocouple is damaged, replace it.

Step 5: Check the Control Board

If the thermocouple is functioning properly, the next step is to check the control board. The control board manages the various components of the water heater and can cause a flame loss if it is damaged or malfunctioning. If the control board is damaged, replace it.

Error Code E015: Abnormal Control Board

This can be as a result of several reasons, consisting of a power surge, a software problem, or a hardware breakdown.

The control panel is responsible for handling all the functions of the hot water heater, including ignition, home heating, and also flow.

When it breakdowns, the mistake code E015 indicates a problem with the control board.

Solution:

The first step in fixing the E015 mistake code is to switch the power off to the water heater.

This will assist in avoiding more damage to the control board and permit you to fix the issue securely.

Once you have shut off the power, you can start by examining the control board for any indications of physical damage, such as fractures, chips, or shed marks.

If you discover any damage, it may be necessary to change the control panel.

If there is no noticeable damage to the control panel, you should check the wiring and connections to ensure they are appropriately secured and not damaged.

If any circuitry or connections are harmed, you have to fix or change them.

If the wiring and links remain in good condition, you might need to update the control panel software.

Finally, if none of these steps resolve the issue, a licensed Navien technician may need to professionally repair or replace the control board.

Navien Tankless Water Heater No Hot Water

One of the most common problems with Navien tankless water heaters is a lack of hot water. If you turn on the hot water tap and only receive cold water, there are several potential causes that you should consider.

• Low water pressure: As mentioned in the error code section, the water pressure in your home must be between 30 and 150 psi. If the pressure falls below 30 psi, you may experience a lack of hot water.
• Inadequate gas supply: If the gas supply to the heater is insufficient, the burners may not ignite, resulting in a lack of hot water.
• Faulty thermostat: The thermostat controls the temperature of the hot water. If the thermostat is faulty, it may not accurately regulate the water temperature, resulting in a lack of hot water.
• Clogged air filter: The air filter helps to prevent debris from entering the combustion chamber. If the air filter is clogged, it can restrict the airflow and reduce the heater’s performance.

Navien Tankless Water Heater Not Igniting

Another common problem with Navien tankless water heaters is ignition failure. If the burners are not igniting, it can result in a lack of hot water and the display of the C7 error code. Here are some potential causes of ignition failure:

• Low gas pressure: If the gas pressure to the heater is too low, the burners may not ignite.
• Faulty igniter: The igniter is responsible for sparking the burners; if it is faulty, the burners will not ignite.
• Dirty burners: Dirt and debris can accumulate on the burners, preventing them from igniting.
• Clogged air intake: As mentioned in the error code section, a clogged air intake can cause combustion problems and prevent the burners from igniting.

Navien Tankless Water Heater Maintenance

Regular maintenance is essential for the longevity and performance of your Navien tankless water heater. Here are some key steps you can take to ensure that your heater is in top working condition:

• Check water pressure: Check the water pressure in your home regularly to ensure that it falls within the recommended range of 30 to 150 psi.
• Clean air filter: Clean the air filter regularly to prevent it from becoming clogged with debris.
• Flush the system: Flushing the system regularly will help remove any buildup of mineral deposits, which can reduce the heater’s performance.
• Descale the heat exchanger: Descaling the heat exchanger is an important step in maintaining your Navien tankless water heater. Mineral deposits can accumulate on the heat exchanger and reduce its performance.

Conclusion

Navien tankless water heaters are convenient and efficient for demanding hot water. However, like all appliances, they are prone to problems. By understanding the most common Navien tankless water heater problems and their reasons, you can take the necessary steps to resolve them quickly and effectively. Whether you prefer to call in a professional or tackle the issue yourself, regular maintenance will ensure that your heater continues to perform at its best.