Navien Tankless Water Heater Error Codes

Is your Navien tankless water heater starting to act like there’s a problem? Is it displaying a strange number but you don’t know what it means? Tankless water heaters aren’t perfect and problems do happen.

Fortunately, Navien is among the manufacturers that make sure an error code is displayed to help you. But, seeing an odd code or number doesn’t exactly help you figure out the issue unless you know what it means. That’s why we’re giving you a breakdown of different error codes right here

Contents

    Navien Tankless Error Codes Breakdown

    Tankless water heater systems involve some complex technology, so errors and issues are bound to happen. Below we have a complete error code list with problems and solutions.

    Error Code E003

    What It’s Telling You

    • There’s an ignition failure.

    The Solution

    1. Make sure that the major gas valve is open.

    Error Code E004

    What It’s Telling You

    • False flame detection.

    The Solution

    1. Confirm that the main electrical cord is accurately grounded.

    Error Code E012

    What It’s Telling You

    • There was a flame loss.

    The Solution

    1. Clean the intake filter: Remove the filter and wash it with a toothbrush under running water. Make sure that the power is off before you remove the filter. Let it dry before placing it back into the unit.
    2. Check the connections: Confirm that the electrical cord is accurately grounded.

    Error Code E016

    What It’s Telling You

    • The heat exchanger is overheating.

    The Solution

    1. Restart the unit: Turn it completely off for 30 minutes minimum, before restarting it.
    2. Clean the inlet filter: Remove it and clean it under running water with a toothbrush.
    3. Flush the heat exchanger: While the cold water inlet filter is out, flush the heat exchanger. Refer to your owner’s manual for exact instructions.

    Error Code E030

    What It’s Telling You

    • The exhaust is overheating: The unit shuts down automatically as soon as the flue pipe exceeds a temperature of 149 degrees Fahrenheit.

    The Solution

    1. Restart the unit: Turn the system off for at least 30 minutes before restarting it.
    2. Wash the inlet water filter: Remove it and wash it under running water with a toothbrush.
    3. Flush the heat exchanger: Consult your owner’s manual for exact instructions.

    Error Code E046

    What It’s Telling You

    • Unusual operation: Limit control.

    The Solution

    1. Call Navien technical support at 1-800-519-8794.

    Error Code E047

    What It’s Telling You

    • Unusual operation: Exhaust thermostat.

    The Solution

    1. Call Navien technical support at 1-800-519-8794.

    Error Code E060

    What It’s Telling You

    • Unusual operation: Dual venturi.

    The Solution

    1. Call Navien technical support at 1-800-519-8794.

    Error Code E109

    What It’s Telling You

    • Unusual operation: Fan motor.

    The Solution

    1. Rinse out the air intake filter: Remove it and wash it under running water. Scrub with a toothbrush. Let it dry and place back into the unit.

    Error Code E110

    What It’s Telling You

    • Unusual air pressure.

    The Solution

    1. Clear blockages: Ensure that there are no obstructions in the exhaust pipe.
    2. Wash the air intake filter: Remove it from the unit and wash it under running water. Scrub with a toothbrush. Let it dry before placing it back.

    Error Code E407

    What It’s Telling You

    • An issue with the hot water outlet: This could be either an open thermistor or a short in the circuit.

    The Solution

    1. Call Navien technical support at 1-800-519-8794.

    Error Code E421

    What It’s Telling You

    • A problem with the first cold water outlet: An open thermistor or a short in the circuit.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E432

    What It’s Telling You

    • An issue with the second cold water outlet: An open thermistor or a short in the circuit

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794

    Error Code E434

    What It’s Telling You

    • Unusual operation: Water adjustment valve.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E438

    What It’s Telling You

    The Solution

    1. External: Check that all the water return and supply lines are free and open.
    2. Internal: Check the direction of the 2-way valve.

    Error Code E439

    What It’s Telling You

    • Unusual operation: Flow sensor.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E441

    What It’s Telling You

    • An issue with the second hot water inlet: An open thermistor or a short in the circuit.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E445

    What It’s Telling You

    • Unusual operation: Bypass mixing valve.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E515

    What It’s Telling You

    • Unusual operation: PCP.

    The Solution

    1. Make sure that the main electrical cord is accurately grounded.

    Error Code E517

    What It’s Telling You

    • Unusual operation: DIP switch setting.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794

    Error Code E593

    What It’s Telling You

    • Unusual operation: Front panel key.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E615

    What It’s Telling You

    • Unusual operation: Memory and input.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794

    Error Code E736

    What It’s Telling You

    • Unusual operation: Problem with internal communication.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E740

    What It’s Telling You

    • Unusual operation: Outdoor temperature sensor.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E760

    What It’s Telling You

    • Maintenance alarm: Flushing or service required.

    The Solution

    1. Contact your installer for routine service.

    Error Code E782

    What It’s Telling You

    • Unusual performance: Issue with the main panel communication.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Error Code E785

    What It’s Telling You

    • Unusual performance: Issue with the flow switch/sensor.

    The Solution

    1. Call Navien’s technical support at 1-800-519-8794.

    Common Navien Tankless Water Heater Problems

    Navien’s tankless water heaters are some of the best on the market today, but they did have a rocky start. In fact, some of their pre-2011 models suffered from some unfortunate issues (source). Some were even recalled (source).

    Fortunately, Navien stepped up and issues have become less frequent. This company was one of the first to produce tankless condensing water heaters for residential use. Issues are bound to happen whenever you step into something new, and Navien’s experience was just that.

    If you have a pre-2011 model, here are some issues you may want to look out for — or have perhaps already experienced.

    Turn the power off

    Before you do anything with your unit, make sure that the power is off. Even though it’s a gas-powered boiler, it still uses electricity. So to avoid a nasty shock, please turn the breaker to the “Off” position.

    1. Motherboard and Control Board Failure

    A common issue involves either the motherboard or control board, or sometimes both. These are the “brains” of the tankless unit, receiving and transporting information around. Unfortunately, when these fail, it can mean that there’s a larger flaw with the boiler itself.

    On Navien’s pre-2011 models, this seems to happen pretty frequently. The symptoms are relatively easy to spot. Your unit will likely turn on and off repeatedly.

    If it doesn’t switch on and off, check the display for the error code E003 — the code for ignition failure. The best way to fix this is simply by unplugging the unit, waiting a little while and then connecting it again.

    If this doesn’t fix the issue, the control board will likely need a replacement. Contact your installer for assistance.

    2. Flow Sensor Corrosion

    One of the most annoying issues with the company’s earlier models was the flow sensors. These were made from a material that was prone to corrosion.

    A flow sensor is an important part of any tankless water heater. Its main job is to sense an incoming flow of water and then activate the unit.

    But, as Navien’s flow sensors corroded prematurely, they caused the units to shut down. A buildup of corrosion would trigger an impaired operation, which could lead to other issues.

    There’s one easy and fast fix to this issue, but it’s only temporary. Here’s what you do: Turn the unit off, locate the flow sensor, gently pull it out and then blow on it. Place it back into the unit and turn the power back on.

    Navien, on the other hand, fixed this issue by improving the flow sensor material. Now, Navien uses stainless steel, which is resistant to rust and corrosion. If you have an older unit, you might be able to replace the part with a new one.

    If this isn’t an option for you, purchase a 5-micron filter and install it by the water inlet valve.

    3. Heat Exchanger Cracking

    Fortunately, this problem isn’t as common as the two above. But, it’s definitely an issue to be aware of.

    If the heat exchanger begins to crack it means there’s a breach, and harmful exhaust gasses could lead straight into your home. An immediate replacement is required and there are no quick fixes to this one. Contact Navien, since the heat exchanger should be under warranty.

    How to Reset a Navien Tankless Water Heater

    If you’re experiencing an issue with your unit but don’t see error codes, you can try resetting it. This is very easy and doesn’t require you to pull any components apart.

    Navien has been smart with its units and fitted a reset button on the front control panel. It generally sits in the lowest corner opposite to the “On/Off” button. To reset your unit, simply press the reset button and you should be ready to go (source).

    However, if you’ve tried this and none of the above error codes apply, contact an authorized technician.

    Where is the Serial Number on a Navien Water Heater?

    Knowing the serial number on your water heater is very important, especially if you need to call the company. Fortunately, locating the label shouldn’t take you long. It usually sits either on the front door or on the side.

    Look to the side of your unit. There should be a large yellow label indicating the energy guide or any warnings. The serial number should be close to these.

    However, if it’s not on the side, the exact location depends on the particular unit. Sometimes it sits on the outside, but other times, you’ll have to open the unit’s door.


    Error Code: Out of Time

    Tankless water heaters are advanced machines capable of producing lots of hot water for our needs. But, they aren’t flawless and issues do happen. Fortunately, Navien included error codes to help you figure out the problem.

    Which error code is your Navien unit showing? Please leave your reply below. If you have further questions, we’ll be happy to answer them.

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