How To Reset Navien Tankless Water Heater [Explained A-Z]

When you see an error code pop up on your water heater, your first instinct should be to reset your water heater. Sometimes, that’ll be enough to clear the error code. So, how to reset Navien tankless water heater?

More often than not, the reset procedure will be incredibly easy and all you’ll have to do is to press the reset button. But once in a while, you’d have to try other methods to reset the heater.

I’ll talk about these methods from my personal experience with both tankless water heaters and combi boilers. So, let’s dive in!

how to reset navien tankless water heater

How To Reset Navien Tankless Water Heater

Resetting Navien tankless water heaters is one of the easiest jobs you’ll ever encounter. That’s because all you’ll have to do is to press the reset button and the rest will happen automatically.

Where Is The Navien Tankless Water Heater Reset Button Location?

You obviously need to know where the reset button is located if you want to reset the unit. Thankfully, Navien doesn’t make it too hard for you to spot the reset button if you look at the unit.

You’ll find the reset button in the front panel of the water heater next to the display panel of the water heater. There’ll also be other buttons like the power button, information button, and temperature adjustment buttons.

Don’t worry, the reset button won’t be hard to detect because the button literally says “RESET” on it. However, there are some newer versions of Navien water heaters where the reset button is a little harder to spot.

reset button of navien tankless water heater

The reset button in such water heaters looks like a backward arrow. If you’re confused as to how it looks, here’s a picture so that you know what you should be looking for:

new reset button of navien tankless water heater

Yes, that’s the reset button in the new Navien water heaters. These heaters are even better to use as they show texts in the display when something is wrong with the water heater. The previous versions would have only shown an error code. Now, you know where the reset button is in all types of Navien heaters.

Why Should You Reset Your Navien Tankless Water Heater?

The reset button in Navien water heaters isn’t there so you can press it for fun. You’d only press it when something is wrong with your water heater. The main reason why most people press the reset button on the Navien water heater is to clear the error codes.

Pressing the reset button can sometimes remove the error code if it came up due to a faulty glitch. While it won’t always do the trick, it’s always recommended to reset the unit first and see if the problem goes away.

How To Hard Reset Navien Tankless Water Heater?

Resetting a Navien tankless water heater is usually a straightforward job. All you have to do is press the reset button and you’re done. But the error code that made you reset the water heater can still remain after that.

In that case, you can try another technique to reset the water heater. Press the power button on the water heater and wait until it goes off. Then, disconnect the water heater from the power outlet.

power button of navien tankless water heater

Wait for a few minutes, plug the water heater back in, and press the power button to turn the water heater on. Hopefully, that’ll get rid of the error code and your water heater will be back to normal. If that doesn’t work, you have to fix the main issue that prompted the error code in the first place.

How To Reset Navien Water Heater After Power Outage?

The process of resetting the water heater after a power outage isn’t too different. The main thing is that you’ll have to turn on the water heater first by pressing the power button first.

Once it has power and is operational or displaying an error code, you can press the reset button and continue the process as usual. If the error code remains even after resetting the water heater, there’s an underlying problem behind it. You can try to fix it yourself or hire a qualified technician for the job.

How To Reset A Navien Boiler?

The process of resetting a Navien combi boiler is the same as resetting the Navien tankless water heater. You’d have to press the reset button and the unit will do the rest on its own. If that doesn’t work, you can turn off the water heater, unplug it, plug it back in, and turn on the water heater.

How To Factory Reset A Navien Combi Boiler?

You have the option of resetting Navien combi boilers to their default settings by performing a factory reset. First of all, you’d have to turn off the combi boiler to do that. Then, press the [Diagnostic]+[Plus]+[Reset]+[Power] buttons all at once for nearly 5 seconds to start the factory reset process.

The supply water temperature is set at 140°F, the return water temperature is set at 120°F, and the hot water temperature is set to 120°F as well under default settings.

Should You Follow Any Additional Steps When Resetting The Water Heater?

Normally, pressing the reset button will reset your water heater. You don’t have to do anything before or after it. But if you still see the error code, you should try to power cycle the water heater.

But I’ve seen a few cases where doing some extra steps took care of the error code. Here are a few things you can do quickly to make sure the reset procedure in your water heater goes smoothly:

i) Turn Off The Water Supply

Turning off the water supply will make sure that the reset process isn’t interrupted. You can make sure that the water supply is turned off by opening a hot water faucet. If no water comes out of it, the water supply is off.

ii) Drain The Water Heater

There are a few steps involved in draining the water heater. I’ve talked about all of them in detail in my Navien water heater maintenance guide. If you do it, the chance of the reset process going smoothly will increase.

draining the navien tankless water heater

iii) Clean The Different Filters

If the filters are dirty, they can make the error code persist even after you reset the water heater. It’s not just the water filters but the air intake filter at the top of your water heater as well.

cold water inlet filter of navien tankless water heater

Dust, leaves, and twigs can often get into the air intake filter and make it dirty. Similarly, the water inlet and recirculation filters can also get dirty. Clean them after you drain the water heater so that the unit can reset without a hitch.

How To Descale A Navien Tankless Water Heater?

Flushing your water heater from time to time is highly important to improve its lifespan. It reduces the amount of minerals or sediments that have built up in the heat exchanger and increases the efficiency of your water heater.

descaling of  navien water heater

If you have a serious hard water supply issue in your house, the water can smell and taste horrible. All these things make it a must to descale the heat exchanger once or twice a year. You can follow these steps to do it:

  1. Remove the front cover of the water heater and clean the air intake filter.
  2. Drain the water heater and clean the water inlet and recirculation filter.
  3. Put the cleaning solution or vinegar in a 5-gallon bucket.
  4. Run the solution through the heater with a recirculation pump.
  5. Keep circulating the solution for at least 30-45 minutes. Then, you can turn off the pump and restore the water heater to its original condition.

Those are the basic steps you have to follow to clean the heat exchanger. If you think I went too fast, there’s no need to panic as I have a dedicated Navien tankless water heater flushing. You can visit it to find out all about the required steps for flushing the heat exchanger in detail.

How To Clear Error Code On Navien Tankless Water Heater?

Sometimes, the error code can come up on a water heater due to a glitch. So, your first course of action should be to reset the water heater. You already know how to do it by now.

If the error code comes up without something being wrong with your heater, it’ll go away once you reset the water heater. If it still remains, you can try cycling the water heater on and off.

Your water heater showing the error code even after trying these things suggests that something is truly wrong with your water heater. For example, the Navien E003 error code comes up due to ignition failure.

A common reason behind it is not fully opening the main gas valve. Check out my guide on fixing the Navien E003 error code to learn how to solve it. Similarly, other error codes can come up due to other reasons.

You can check the owner’s manual to find out the specific information about the error code you’re facing. Then, take the appropriate steps to fix that issue. I also have a dedicated guide on clearing Navien tankless water heater error codes. You’ll find the common error codes and their fixes in detail in there.

How To Use Commercial Mode In Navien Water Heaters?

If your water heater allows you to use commercial mode, you can do it easily. The main benefit of using commercial mode is that you can set the heater above 140°F. You wouldn’t be able to do it if you used the heater in normal mode. So, how do you get in and out of commercial mode?

Press both the temperature adjustment buttons (+ and -) together for 10 seconds until the word “High” appears on the display. Similarly, you can exit commercial mode by doing the same thing if you’re already in that mode.

Once you’re in commercial mode, the process of adjusting the temperature is simple. It’s just like you would increase or decrease the temperature using the + and – buttons.

If you want to adjust the temperature by a large degree, you’ll have to hold the adjustment buttons for 5 seconds. The temperature will also change by 10°F each time. You can’t set the interval lower than that if you use this mode.

Keep in mind that your warranty will be shifted to a commercial warranty rather than a residential one if you keep using this mode for a long period. You can reach out to Navien about this matter if you want more information and don’t want to risk breaching your warranty.

How To View Basic Information In Navien Water Heater?

You’ll have to press the information button if you want to know some basic things about your water heater. It’s the button with the letter “i” covered by a circle. Here’s a picture to help you out:

information button of  navien water heater

After getting into this mode, the flow rate, hot water outlet temperature, and cold water inlet temperature are the types of information you can check. You’ll only be able to see one of them at a time. The flow rate is measured in GPM, and you’ll see the temperatures in Fahrenheit degrees.

You’ll be able to see only one piece of information at a time. Press the + and – button to switch between these different data types. If you want to exit the information mode, place the reset button. Then, you’ll go back to the default display mode of the water heater. 


Should you set the temperature to 140°F or above using the commercial mode option?

Whenever you set the temperature above 120°F, you open yourself up to the risk of scaling. So, increasing the hot water outlet temperature to 140°F is never recommended for safety reasons.

What does the Navien water heater standby mode mean?

One of the reasons that you get a low bill when using tankless water heaters is that they only become active when needed. The standby mode enables the water heater to do that as it saves energy when there’s no need for hot water.

What is the highest temperature you can set in Navien tankless water heaters in commercial mode?

When you want to set the temperature above 140°F, you need to use commercial mode. You can set the temperature to a maximum of 182°F if you use the heater in this mode.

Should you use your water heater if it has been underwater?

No, a water heater that’s gone underwater can be damaged as there are different types of wiring inside it. So, don’t try to turn it on or reset it. In fact, consult a technician and have them check whether your heater is fit for use.


How to reset Navien tankless water heater? Now, you know all about it in detail and how you can also use the power cycle technique to reset the heater. Hopefully, you’ll find the tips on viewing information and using the commercial mode in your heater beneficial.

Keep in mind that resetting the water heater won’t always solve the problem. You’d have to fix the underlying problem when needed. Check out my Navien tankless water heater maintenance guide to take good care of your heater and prevent the error code from coming up in the first place.

Leave a Comment