How To Clear Codes On Navien Tankless Water Heater - Your Complete DIY

There’s nothing quite like the jolt of a cold shower to ruin your morning. You glance at your Navien tankless water heater, and there it is—a blinking, unfamiliar error code on the digital display. It’s a moment of frustration every homeowner dreads, leaving you wondering if a simple fix or a costly repair call is in your future.

Don’t worry. That error code is your unit’s way of talking to you, and we’re here to help you translate. We promise this guide will walk you through everything you need to know about how to clear codes on navien tankless water heater safely and effectively.

In this article, you’ll learn not just the simple steps to reset your unit, but also how to understand what those codes mean, what to check before you reset, and the crucial signs that tell you it’s time to put down the tools and call a professional. Let’s get that hot water flowing again!

Why Your Navien is Showing an Error Code (And Why You Shouldn’t Ignore It)

First things first, an error code isn’t a sign that your water heater is broken beyond repair. Think of it as a helpful diagnostic message. Your Navien’s sophisticated internal computer is constantly monitoring dozens of parameters—from water flow and gas pressure to exhaust temperature.

When one of these parameters goes outside its normal operating range, the system displays a code and often shuts down. This is a safety feature designed to protect both you and the appliance from potential damage.

Simply clearing the code without addressing the root cause is like hitting the snooze button on your smoke detector. You might get temporary silence, but the underlying danger remains. Understanding the “why” is the first step in our how to clear codes on navien tankless water heater guide.

Before You Reset: Essential Safety First Steps

Before you even think about pressing a button, let’s do a quick visual inspection. Many error codes are triggered by simple, external issues that you can spot and fix in minutes. Taking a moment to check these things can save you a lot of time and hassle.

Check for Obvious Issues

Walk over to your unit and perform these basic checks. This is one of the most important how to clear codes on navien tankless water heater tips we can offer.

Power Supply: Is the unit plugged in securely? Has a circuit breaker tripped? Go to your electrical panel and make sure the breaker labeled for your water heater is in the “ON” position.
Gas Supply: Find the gas line leading to your Navien. Ensure the valve handle is parallel (in line) with the pipe, which indicates it’s open. If it’s perpendicular, it’s closed.
Water Valves: Check the hot and cold water lines connected to the unit. Just like the gas valve, the handles should be parallel to the pipes to be fully open.
Ventilation Pipes: Look outside where your unit’s intake and exhaust pipes terminate. Are they blocked by leaves, snow, a bird’s nest, or other debris? A blocked vent is a common cause for shutdown codes.

Identify and Understand the Error Code

Your Navien manual is your best friend here. Don’t have it? A quick search online for “Navien [Your Model Number] manual” will usually bring up a PDF version.

Write down the exact error code displayed on the panel (e.g., E003, E110). Look this code up in the manual’s troubleshooting section. It will tell you the likely cause. Here are a few common ones to give you an idea:

Code E003: This typically points to an “Ignition Failure.” It could be a gas supply issue, a problem with the igniter, or a flame sensor that needs cleaning.
Code E110: This often indicates an “Exhaust Overheat” or blocked vent pipe. This is a serious safety issue, so double-check those pipes for blockages.
Code E012: This usually means “Flame Loss” during operation. The flame ignited but then went out unexpectedly.

Knowing the potential cause gives you context. If the code is for a blocked vent and you find a bird’s nest in the pipe, clearing the code after removing the nest will likely solve the problem for good.

The Complete Guide on How to Clear Codes on Navien Tankless Water Heater

Once you’ve done your initial safety checks and have an idea of what the code means, you can proceed with a reset. There are two primary methods for this. We’ll start with the simplest one. This is the core of our how to how to clear codes on navien tankless water heater instructions.

Method 1: The Simple Power Cycle Reset

This is the classic “turn it off and on again” technique. It works for temporary glitches or for clearing a code after you’ve fixed the external issue (like a blocked vent). It’s one of the first and foremost best practices to try.

Power Down the Unit: Locate the power button on the front control panel of your Navien. Press and hold it for a few seconds until the screen goes blank and the unit powers down.
Wait Patiently: Do not immediately turn it back on. Wait for at least 60 seconds. This allows the internal capacitors to fully discharge and the main control board to perform a complete memory reset.
Power It Back On: Press the power button again to restart the unit.
Observe: Listen carefully. You should hear the unit go through its startup sequence. Watch the display to see if the error code reappears. If all is well, it will return to its normal temperature display.

Method 2: The Hard Reset (Cycling Power at the Breaker)

If the power button reset doesn’t work, or if the unit seems completely unresponsive, a hard reset is the next step. This ensures all power is cut from the unit, forcing a more definitive reboot.

SAFETY WARNING: Always use caution when working with your home’s electrical panel. Ensure your hands are dry and you are standing on a dry surface.

Locate the Breaker: Go to your main electrical panel and find the circuit breaker dedicated to your tankless water heater. It should be clearly labeled.
Turn Off the Breaker: Firmly flip the breaker switch to the “OFF” position.
Wait a Full Minute: Just as before, patience is key. Give it a solid 60 seconds to ensure the unit’s internal electronics are fully powered down.
Turn On the Breaker: Flip the breaker switch back to the “ON” position.
Check the Unit: Return to your Navien water heater. It should automatically begin its startup process. Check if the error code has cleared.

What to Do When the Error Code Comes Back Immediately

So you performed a reset, but the pesky error code popped right back up. This is a clear signal from your Navien that the underlying problem has not been resolved. This is where we address the common problems with how to clear codes on navien tankless water heater that a simple reset won’t fix.

Do not keep resetting the unit. This can put stress on the components and mask a more serious issue.

Re-Investigate Common Problems

It’s time to play detective again, but this time a little more deeply.

Condensate Drain: High-efficiency units like Navien produce condensation. There is a small plastic tube or pipe at the bottom of the unit that drains this water away. If this line gets clogged with debris or freezes in the winter, it can back up and trigger a shutdown. Ensure it’s clear.
Water Inlet Filter: There is a small filter screen on the cold-water inlet of your unit. Over time, it can get clogged with sediment, restricting water flow and causing errors. You can carefully turn off the water, unscrew the connection, and clean this filter.
Flame Sensor: Over time, the flame sensor rod can get coated with carbon buildup, preventing it from detecting a flame correctly. Cleaning this is a common maintenance task, but it requires opening the unit’s cabinet. If you’re not comfortable with this, it’s best to call a pro.

The Benefits of Proper Maintenance: Preventing Codes in the First Place

The best way to deal with error codes is to never see them at all. This is where our how to clear codes on navien tankless water heater care guide comes in. Regular maintenance not only prevents nuisance shutdowns but also extends the life of your unit and keeps it running at peak efficiency.

One of the biggest benefits of how to clear codes on navien tankless water heater proactively is peace of mind and lower energy bills. A well-maintained unit is a more sustainable how to clear codes on navien tankless water heater solution.

Your primary maintenance task is an annual system flush, also known as descaling. This involves circulating a vinegar or descaling solution through the unit to remove mineral buildup (scale) from the heat exchanger. Hard water is the enemy of tankless water heaters, and this single task can prevent a host of flow- and temperature-related error codes.

Frequently Asked Questions About Clearing Navien Error Codes

Can I damage my Navien by resetting it too often?

While a single reset is harmless, repeatedly power cycling the unit when an error code persists is not a good idea. It can cause unnecessary wear on electronic components and, more importantly, it ignores the root problem, which could lead to a more significant and expensive failure down the line.

Is there a physical reset button on a Navien tankless water heater?

Unlike some older appliances, Navien units typically do not have a small, red, recessed “reset” button. The reset procedure is performed by cycling the power, either via the power button on the front panel or by using the circuit breaker, as we’ve outlined in this guide.

What is the most common Navien error code for homeowners?

While it varies by model and installation, some of the most common codes relate to ignition failure (like E003) or venting/exhaust issues (like E110). These are often caused by interruptions in the gas supply, dirty sensors, or blocked vent pipes—many of which can be addressed with the checks in this guide.

When should I absolutely call a professional?

You should call a licensed technician immediately if you smell gas, see water leaking from inside the unit’s cabinet, or if you receive a persistent error code that you cannot resolve with the basic checks and resets. Any task that requires opening the main cabinet and working on gas or electrical components should be left to a trained professional.

Clearing an error code on your Navien tankless water heater is often a straightforward process. By following these safe, logical steps, you can troubleshoot many common issues yourself. Remember to start with the simple checks, understand what the code means, and then perform a proper reset.

But most importantly, listen to what your water heater is telling you. A persistent code is a call for help. Embracing a little proactive maintenance will ensure your unit operates safely and efficiently for years to come. Here’s to safe resets and an endless supply of hot water!

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David Clark

Founder & Lead HVAC Specialist at HVACRLY

David Clark is the founder of HVACrly and a certified HVAC specialist with 10+ years working on residential and light-commercial systems. He turns complex heating, cooling, ventilation, and refrigeration topics into clear, actionable guides focused on safety and energy efficiency. When he’s not on a service call, he’s testing tools and writing step-by-step tutorials.