Colton Deck

By: Colton Deck on February 23rd, 2023

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Most Common Navien Tankless Water Heater Error Codes and How to Fix Them

Tankless Water Heaters

Technology is finicky, and tankless water heaters are no different. Over the course of your Navien tankless water heater’s lifespan, you’ll likely run into more than one error code. Don’t worry, though, as error codes are more common than you’d think. 

We’ve been servicing tankless water heaters for over 15 years, and Navien is one of our partner brands. Having a relationship with Navien gives us special insight into what makes these tankless water heaters tick, and that includes diagnosing and addressing common error codes.

In this article, we’ll touch on the most common Navien tankless water heater error codes and how they can be fixed. Spoiler alert: you’ll likely need the help of a technician. 

Before we get into things, we wanted you to know that unplugging and plugging your Navien tankless water heater won’t solve any issues you’re having. Similar to a check engine light on a car, just because you disconnected the battery and the light went away doesn’t mean the problem is resolved. 

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Now, let’s jump in with a common one for Southern Californian residents. 


Most Common Navien Tankless Water Heater Error Codes


Error Code 016

If you’ve run into this error code, it means there’s likely an issue with your heat exchanger. Technicians most commonly see this error code with tankless water heaters experiencing calcification in the unit’s heat exchanger. This issue can lead to any number of issues, including overheating, pinhole leaks, and issues with the flow sensor. 


Next Steps

The first step for pretty much any error code is to get a technician out to your property as soon as possible. Your technician should then inspect the tankless water heater, as well as the entire plumbing system, to determine the root of the problem. 

If you’ve kept up on maintenance and your tankless water heater isn’t too old, the technician will run vinegar through the tankless water heater to descale it. This process should clear the error code. 

If your tankless water heater has never had maintenance performed and is older, you may have to get a new heat exchanger since a cleaning won’t be enough to cut it. 


Error Code 012

If you run into this error code, you likely ran into no running hot water first. This error code signals flame loss, which a couple of things can cause. Gas pressure issues or an internal leak could trigger the error. 

Additionally, your gas line could be undersized, causing a lack of gas entering the system. You might also have a bad regulator. In very rare cases, there could be a faulty gas valve within the tankless water heater.

Until this error code is addressed, you won’t have hot water running through your home. 


Next Steps

Again, you’ll need to call a technician out immediately to diagnose and resolve this issue. Given the variety of causes for error code 012, your technician will inspect your tankless water heater and plumbing system to determine the cause of the issue. 

An important detail to note is that if your technician finds a bad regulator in your system, the gas company will need to come out to replace it. 


Error Code 11

Error code 11 earns a spot as one of the most common error codes for good reason since it is easily triggered. This error code is associated with having no ignition, meaning you won’t be getting any hot water to your home. 


Next Steps

Like every other error code listed, you’ll need a technician to resolve the error code properly. In most cases, your technician will likely report that the earthquake shut-off valve was triggered. This component can be activated by something as simple as hitting the tankless water heater with a grange can on the way to take it to the street. 

If the earthquake shut-off valve hasn’t been triggered, then you’re most likely looking at a lack of gas entering the unit. A dirty gas manifold typically causes this issue, in which case, your technician will give the component a good cleaning. 

As with any issue, yearly maintenance is the best way to prevent problems like a dirty gas manifold. 


Error Code E004

If you run into error code E004, your Navien tankless water heater is running into false flame detection. This issue means that the sensor that detects light is not picking up the flame. This error code is less common than the others listed above but still pops up relatively frequently. 


Next Steps

After calling a technician out, the root of the problem will likely be a leak in the heat exchanger or circuit board issue, exhaust or intake blockage, or a mixture. 

If there is a blockage in the venting system, it may have caused a short in the circuit board, causing the E004 error code to display. If this is the case, your technician will clean the system of blockages and sort out the circuit board. 

On the flip side, the repairs may have to be more comprehensive if the issue is a leak in the heat exchanger. Your technician may need to rebuild the system or replace the heat exchanger outright. 

This is another error code that is easy to prevent with regular yearly maintenance. 


Brushed Up on Navien Tankless Water Heater Error Codes

We’ve talked about the most common Navien tankless water heater error codes our technicians run into so you can better understand what you might see on your own Navien model. Now, you can confidently take the right steps should you run into one of these error codes. 

With over 15 years of tankless water heater experience under our collective belts, we’re confident in approaching any Navien error code. Thanks to being one of our partners, we keenly understand Navien tankless water heaters inside and out. One thing we can tell you about any tankless water heater is that the best medicine is preventative, so don’t skimp out on yearly maintenance. 

If you have questions about an error code displaying on your Navien tankless water heater or would like to schedule a maintenance appointment, visit our tankless water heater service page or click one of the buttons below to schedule a consultation. 

If you’ve never really explored your tankless water heater, download our Navien Tankless Water Heater Guide to get up to speed on your investment. Additionally, if you want to prevent error codes to the best of your ability, you can hedge your bets by educating yourself on the types of maintenance a tankless water heater needs. 

For a deeper look at Navien as a brand, read our full review here