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Last updated: 16th April, 2024


Navien Boiler Error Codes

Navien Boiler Error Codes

Key takeaways

  • When your Navien boiler starts displaying error codes, it's the system's way of communicating that something isn't working correctly.
  • We always recommend contacting a Gas Safe registered engineer to troubleshoot and solve any boiler problems.
  • If your boiler is over ten years old and constantly requires repairs, it might be time to consider upgrading to a new system.

Troubleshoot common Navien boiler error codes with iHeat, a leading UK provider of heating solutions. Discover the importance of professional, Gas Safe registered interventions and the value of upgrading your boiler system

Navien boilers are renowned for their efficiency and durability. However, like any complex system, you may encounter some common Navien boiler error codes that indicate a need for maintenance or repair. 

As a leading UK provider of heating solutions, iHeat is here to help you decipher these error codes and guide you through appropriate solutions. We also emphasise the importance of letting Gas Safe registered engineers address these boiler issues.

Moreover, we'll discuss the potential benefits of upgrading your boiler system when recurring issues become a bother.

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Check out our 2023 Navein NCB boiler review for more information!

Understanding Navien Boiler Error Codes

When your Navien boiler starts displaying error codes, it's the system's way of communicating that something isn't working correctly. Here are a few common Navien boiler error codes:

Navien Boileer Error Code 001 (Ignition Issue)

One of the most common Navien boiler error codes is 001, indicating a problem with the boiler's ignition. 

When you see this error code on your Navien boiler, it typically means that there's a fault with the ignition leads, the spark electrode, or the gas valve. 

These components are vital for the boiler to function correctly, and any issues can prevent the boiler from igniting and delivering heat to your home. 

The cause can range from dust and dirt buildup that disrupts the ignition process to electrical faults within the boiler. 

When dealing with this error code, iHeat highly recommends getting the help of a Gas Safe registered engineer who can clean and inspect the components, identifying the exact issue. 


In some cases, the solution might involve replacing the faulty parts to restore proper ignition. Regular maintenance checks can also help prevent such issues, ensuring your boiler works smoothly throughout the colder months.

Navien Boiler Error Code 002 (Exhaust Sensor Problem)

The second common Navien boiler error code that homeowners often encounter is 002. This error code signifies an issue with the boiler's exhaust sensor, which plays a crucial role in ensuring the boiler's safe operation. 

Sensor malfunctions could lead to unsafe conditions, often due to sensor degradation over time or electrical faults within the boiler. 

If you encounter this error, calling in a Gas Safe registered engineer should be your first step. They can replace the faulty sensor and restore your boiler to safe and efficient operation. 

Like with all boiler components, regular service and checkups can help detect such issues earlier, saving you from any unexpected breakdowns in the middle of a chilly night.

Navieen Boiler Error Code 003 (Water Pressure Problem)

Error code 003 on your Navien boiler indicates a problem with water pressure in the system. Low pressure can be due to a leak within the boiler system or an issue with the pressure relief valve. 

High pressure, on the other hand, might signal a fault with the pressure sensor or expansion vessel. 

These issues can affect your boiler's performance and efficiency, making your home less comfortable. 

iHeat's team of Gas Safe registered engineers is skilled in identifying the exact cause of water pressure issues and rectifying them. The solution could involve fixing leaks, replacing the valve, or resetting the pressure. 

Again, regular maintenance can help detect leaks or valve issues early, preventing this error code from appearing.

Navien Boiler Error Code 012 (Flue Issue)

If your Navien boiler displays error code 012, it means there's an issue with the flue. The flue carries away waste gases safely and any blockages or leaks can lead to serious problems. If a blockage is found, it needs to be safely removed by a Gas Safe engineer. 

If a leak is detected, the affected parts might need replacement. A regular service schedule can help prevent such issues, ensuring that your flue always works effectively and safely.

Navien Boiler Error Code 015 (Temperature Sensor Issue)

The final error code we'll discuss is 015, which signifies a problem with the boiler's temperature sensor. This sensor monitors the water temperature and communicates with the boiler's control system to ensure optimal operation. 

A fault here could be due to wear and tear over time or an internal boiler fault causing the sensor to give inaccurate readings. 

A Gas Safe registered engineer can replace the sensor or fix the underlying issue causing the inaccurate reading. Regular servicing can help detect such issues before they result in a complete shutdown of your Navien boiler.

While these error codes provide a glimpse into what might be going wrong with your Navien boiler, they're just a piece of the puzzle. A Gas Safe registered engineer from iHeat can interpret these codes in the context of your boiler's overall condition to provide a comprehensive solution.

Check out our 2023 Navein NCB boiler review for more information!

Gas Safe Registered Engineers

Attempting to identify and rectify boiler issues yourself can be both dangerous and potentially costly, especially if you're not professionally trained. 


At iHeat, we firmly believe that your safety is paramount. That's why we always recommend contacting a Gas Safe registered engineer to troubleshoot and solve any boiler problems.

Our Gas Safe registered engineers have undergone extensive training and assessment, ensuring they're competent to work safely and legally with gas appliances. They're equipped with the knowledge and tools to accurately identify and rectify faults, thereby minimising potential risks.

Having a Gas Safe registered engineer from iHeat deal with your boiler issues does not only mean a professional diagnosis and repair, but also peace of mind knowing that your boiler is operating safely and efficiently.

Considering a New Boiler?

While addressing the error codes can resolve many boiler issues, if your boiler is over ten years old and constantly requires repairs, it might be time to consider upgrading to a new system.

A new boiler offers numerous benefits, including enhanced efficiency, potentially leading to lower energy bills. 

Modern boilers are also designed with the latest technology for improved performance and user convenience. They're often quieter, smaller, and easier to operate than older models.

New Boiler Costs - quick and simple breakdown


Boiler Types


Combis or combination boilers, combine all components and aspects of a heating system (central heating and hot water production) into one succinct and powerful unit.

Their economic size, quick flow rates and dual functionality means combis are extremely efficient and effective when heating a multitude of property sizes, being best suited for small to medium sized homes with 1-2 bathrooms.

Does a combi boiler sound ideal, well here’s a list of our favourite new combi boilers


System boilers perform best in homes with a high hot water demand, specifically either larger properties with a higher number of residents or properties with two or more bathrooms. 

System boilers store hot water in a separate cylinder which provides constant flow access but requires additional (minimal) storage space.

System boilers can service multiple flow outlets at one time, meaning no one in a larger home would be standing around waiting for a shower.

Heat Only

A heat only boiler provides the heat for a home's central heating system and hot water cylinder. A heat only boiler is suited to servicing larger properties with multiple bathrooms/radiators or a business premises with a high water demand. 

Heat only boilers do require sufficient installation space within a property, as they use two storage tanks (feed & expansion) as well as the aforementioned hot water cylinder. 

Although a combi is generally considered more space saving, a modern heat only boiler is still compact and can supply more bathrooms with hot running water than a combi can.


At iHeat, we can guide you in choosing a boiler that best suits your home's heating and hot water needs, ensuring optimal performance and efficiency. We offer a range of modern boilers, all installed by our team of Gas Safe registered engineers. 

With extended warranty options and excellent customer service, upgrading your boiler with iHeat is a decision you can be confident in.

Understanding common Navien boiler error codes and dealing with them appropriately is the first step to a well-maintained boiler. 

However, remember that any tinkering with your boiler should be left to Gas Safe registered professionals.  

When recurring issues become a nuisance, rest assured that upgrading to a new boiler is a worthy investment for your comfort, safety, and pocket. Trust iHeat to guide you through every step of the way.

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Frequently Asked Questions

How Do I Manually Reset My Navien Boiler?

To manually reset a Navien boiler:

  • Locate the Reset Button: This button is usually prominently displayed on the front panel of the boiler.
  • Press the Reset Button: Press and hold this button for a few seconds until the boiler control panel indicates that it has reset. This may involve the boiler shutting down and restarting.
  • Observe the Boiler: After resetting, watch the boiler's operation to ensure it starts properly and check if the error code clears. If the code persists, further troubleshooting may be necessary.

How Do I Check My Navien Error Code History?

To check the error code history on your Navien boiler:

  • Access the Control Panel: Turn on the boiler's main display.
  • Navigate to the Error History: Use the menu buttons to scroll through to the diagnostics or error log section.
  • Review Error Codes: Here you can see a list of past error codes, which can help diagnose ongoing or past issues.

What are Boiler Fault Codes?

Boiler fault codes are specific alphanumeric codes that appear on your boiler's display. They indicate particular issues within the boiler system, such as problems with sensors, circuits, or mechanical components. Each code corresponds to a different problem, providing a quick way for homeowners and technicians to identify and address faults.

What Does E302 Mean on Navien Boiler?

Error code E302 on a Navien boiler indicates a flame detection problem. This could be due to issues such as:

  • The flame rod is dirty or faulty.
  • The burner is malfunctioning.
  • There is insufficient gas flow or pressure.

This error requires immediate attention to ensure the boiler operates safely and efficiently.

What is Error Code 10E on Navien Boiler?

Error code 10E on a Navien boiler typically signifies a problem with the air pressure switch, which can occur due to:

  • Blockage in the vent system.
  • Failure of the air pressure switch itself.
  • Issues in the electrical connections to the air pressure switch.

This switch is crucial for ensuring safe operation, as it monitors the boiler’s internal pressure.

What is Code 022 Navien?

Code 022 on a Navien boiler often points to an issue with the exhaust thermistor, which is responsible for monitoring the temperature of the exhaust gases. Problems might include:

  • A faulty thermistor.
  • Incorrect readings due to buildup or debris.
  • Wiring issues affecting the thermistor's operation.

What is Code E 302 Navien?

Code E302, as mentioned, indicates a problem with flame detection in a Navien boiler. This error can prevent the boiler from firing up and is typically a sign of issues in the ignition or gas supply system, necessitating thorough inspection and potentially complex repairs.

Stephen Day profile photo
Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.