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Home»Navien troubleshooting manual for water heaters

Navien troubleshooting manual for water heaters

navien troubleshooting manual for water heaters

Navien is a renowned brand known for producing high-quality, energy-efficient tankless water heaters. These appliances are designed to provide homeowners with a reliable and continuous supply of hot water. However, many times, homeowners are faced with issues that they have to troubleshoot themselves before calling in a professional.

In this article, we’ve written a detailed manual for troubleshooting your water heater in easy steps and understand each problem that is stopping your water heater from proper operation.

Common Problems and Troubleshooting Solutions for Navien Tankless Water Heaters

Possible Causes:

Possible causes of this problem include a blocked water filter, an improperly adjusted mixing valve, or a broken water flow sensor, all of which affect the water temperature immediately as it exits the heater.


The first thing to do is make sure the flow sensor is clean or in good repair by inspecting it for any debris or damage. Make sure the water can flow freely by checking and cleaning the water filter. In case the mixing valve isn’t keeping the hot and cold water mixed consistently, you may need to make adjustments or perhaps replace it.

Possible Causes:

The ‘cold-water sandwich’ effect occurs when the heat exchanger’s heated water runs out and the heater releases cold water for a short period before re-heating the water arrives.


Although this is a typical feature of tankless systems, it can be minimized by making sure your unit is appropriately scaled for your home’s demand. You can also get around this issue by upgrading to a model that has a built-in recirculation pump or buffer tank, like some of the more expensive Navien models. If you install it and see an abnormal circulation pump, you’ll know what needs to be fixed.

Possible Causes:

When this happens, it’s usually because of a problem with the venting system, either a leak, a blockage, or a faulty installation.


Look for any connections or obstacles along the whole venting system. Verify that the vent pipes have been installed following Navien’s specifications and are adequately sealed. If you’ve noticed this issue because of an error code, reset the unit after making any adjustments.

Possible Causes:

Scale formation in the heat exchanger, silt buildup in the water filter, or a decrease in overall water pressure from the supply can all cause a low flow rate.


Rinse the heat exchanger with a solution of vinegar or use an industrial-strength descaling agent. Replace or clean the water filter as needed. If the issue continues, you can either install a water pressure booster or inspect the municipal water supply for any problems.

Possible Causes:

Inadequate water flow to cool the heat exchanger, clogged vents, or a broken thermostat are all potential causes of overheating.


By cleaning filters and inspecting all faucets for flow limits, you may ensure that the minimal flow rate is achieved. Check the intake and exhaust vents for any obstructions. It could be required to replace the thermostat if these solutions do not work.

Possible Causes:

Wet or corroded igniter electrodes, improper ground wiring, or natural gas supply concerns are some of the causes of ignition failures in tankless water heaters.


Inspect the igniter for corrosion or damage, and if found, replace it. Put an electrical cord and plug in each outlet and make sure it’s dry. Before powering on the unit, make sure the gas valve is completely open and the gas pressure is correct.

Possible Causes:

Leakage inside the device, caused by damaged internal components, failing gaskets, or seals, is indicated by this fault.


Look for clear indications of water leakage inside the appliance. Be sure to inspect all connections, particularly those near the water intake and outflow. Expert repair or part replacement may be necessary in the event of an internal tank leak.

Possible Causes:

An unstable power source, an inconsistent gas supply, or a faulty control panel could be the cause of your unit’s frequent need for resetting.


Make sure the device is hooked up to a reliable power source. Make sure there are no breaks in the gas line. A replacement of the control panel may be necessary if it keeps breaking even with stable utilities.

Possible Causes:

An unanticipated spike in energy costs could be attributed to the heater’s inefficiency, which can be brought on by scale buildup, improper installation, or malfunctioning parts that force the unit to work harder to heat water.


The heat exchanger may be kept in good working order with regular maintenance such as descaling and alignment checks. Furthermore, check the device for any worn-out components or settings that can cause increased energy efficiency, and fix or replace them as needed.

Navien Error Codes for Water Heaters

Error Code E003: Ignition Failure

  • Cause: When the heater is unable to light the gas, this error usually occurs. A gas valve that is closed, an inadequate gas supply, or an igniter that is malfunctioning are all potential causes.

  • Solution: The solution is to check the gas supply and make sure the gas valve is open. Look for broken or disconnected parts on the igniter. It may be required to inspect the ignition-related electrical components and wiring if the problem continues.

Error Code E004: False Flame Detection

  • Cause: A grounding or electrical problem is frequently to blame when the system detects a flame even if there isn’t one.

  • Solution: One possible solution is to make sure the ground wire is safely connected. Check that the igniter and flame rod are clean and working properly.

Error Code E012: Flame Loss

  • Cause: The unanticipated extinction of the flame is the source of this code. A malfunctioning gas valve, low gas pressure, or air in the gas line are common reasons.

  • Solution: As a solution, you should check that the gas pressure is within the correct range. Find any air pockets in the gas line and make sure the gas valve is working properly.

Error Code E515: Abnormal Operation of PCB

  • Cause: power supply surges or grounding problems may be to blame for the Printed Circuit Board’s odd signals or operations.

  • Solution: Find out whether the electrical connections are properly grounded. Look for broken or malfunctioning components on the PCB. If the problems persist after resetting the device, it may be necessary to replace the PCB.

Error Code E760: Time to Flush Your Water Heater

  • Cause: Scale and silt buildup inside the heat exchanger is the root cause of its diminished efficiency and performance.

  • Solution: The answer is to flush the system as directed by the manufacturer’s manual. This usually involves cleaning the heat exchanger with a vinegar solution.

Error Code E021 & E022: Thermistor Problems

  • E021 (Cold Water Inlet: Thermistor 1 – Open): This code means that the first thermistor on the cold water inlet is currently open.

  • E022 (Cold Water Inlet: Thermistor 1 – Short): This code signifies that the thermistor has experienced a short circuit.

  • Solution for Both: Make that there are no broken or loose connections on the thermistor. If the thermistor seems to be malfunctioning, replace it.

Error Code E007 & E008: Hot Water Outlet Thermistor

  • E007 (Open): The thermistor circuit is not connected, which could be because a wire is broken.

  • E008 (Short): Possible causes of the E008 (Short) error code include water damage or a thermistor that is not working properly.

  • Solution for Both: Take a look at the thermistor’s connections and wires. If the thermistor needs replacing, you can do so.

Error Code E010: Abnormal Air Pressure

  • Cause: Airflow is obstructed, which could be because of an exhaust vent or a blocked flue.

  • Solution: The solution is to make sure there are no leaks or clogs in the venting system. Make sure that the vent pipe is free of obstructions and make sure all the connections are tight.

Error Code E016: Overheating of Heat Exchanger

  • Cause: The heat exchanger is getting excessively hot, which could be because of scale accumulation or a lack of water flow.

  • Solution: The solution is to turn off the machine and allow it to cool down. Make sure the heat exchanger is free of scale by cleaning it. Make sure that there are no clogged filters or closed valves preventing water from flowing through the heater.

Error Code E030: Exhaust Overheat

  • Cause: The high exhaust temperature could be the result of inadequate ventilation or foreign objects obstructing the exhaust flow.

  • Solution: Make sure there are no obstructions in the exhaust stream. Make sure there is no obstruction or debris in the vent pipe and check that it was installed correctly.

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Water Heater Troubleshooting Guides

Our comprehensive troubleshooting guide offers step-by-step solutions to common issues. From heating failures to airflow problems, we've got you covered."

Regular Maintenance Tips for Navien Water Heater

Your tankless water heater cannot function properly or safely without adequate ventilation. Make sure to check the venting system for any obstructions, debris, or damage regularly. Nests can be constructed by insects or birds in vent outlets, particularly in the spring.

Remove any blockages and inspect for corrosion or wear that can diminish performance. Exhaust leaks pose safety risks and reduce efficiency, so make sure all vent components are tightly linked and sealed.

To keep dust and other particles out of your heater and off the combustion process, use an intake air filter. Turn off and cool down the machine before cleaning the filter. In most cases, you’ll need to open an access panel to remove the filter, but see your owner’s handbook for specific instructions.

Rinse the filter well after washing it with warm, soapy water. Reinstall the filter only once it has dried fully. Every three to six months, or as needed based on your surroundings and usage patterns, you should do this.

Cleaning the water filter in a tankless water heater is something that many homeowners forget to do. Incoming water is screened by the water filter to remove trash and silt. Turn off the water supply and release system pressure as directed by the manufacturer to clean the filter. Take the filter out of the unit and wash it under running water; it’s generally by the inlet. Check the water pressure sensor frequently to understand if there are any issues.

Scrubbing the filter gently with a soft brush will remove stubborn deposits. Get the water flowing again by putting the filter back in place. If you live in a region with particularly hard water, you may need to clean the water filter more often than once every two to three months.

The effectiveness of your water heater and the heat exchanger are both compromised by scale accumulation caused by hard water. To descale, you need to run vinegar or a dedicated descaling solution through the machine to dissolve and remove the scale.

If your home has hard water, you may need to do this more often than once a year, but it is still highly advised. To keep the device in good working order, you should only ever use the solution that the manufacturer suggests.

To clear the unit’s pipes and heat exchanger of sediment and scale, it is necessary to flow clean water through the system during a flush. As a result, the water flow and heating efficiency are both preserved and you get endless hot water without any issues. Descaling and system flushing are complementary processes, however, flushing the system is always a good idea if you see a drop in water flow or heating capacity.

Get a professional to check for gas leaks, adjust the flame properly, and evaluate the unit’s overall condition once a year. In addition to that, they can update the software, inspect the electrical connections, and make sure the device is running at full speed following current safety requirements and manufacturer standards.

Expert Navien Water Heater Services by Comfort Union

At Comfort Union, we recognize the value of having a reliable and efficient water heater in your house. That’s why, among all things HVAC, we are experts at servicing Navien tankless water heaters to the highest standards. In order to keep your Navien system running at its best, our certified experts have the knowledge and equipment to fix any problem that may arise.

Why Choose Comfort Union for Your Navien Water Heater Maintenance and Repair:

  • Specialized Expertise: Our staff has substantial knowledge and expertise working with Navien products, thanks to our specialized training. With this in-depth expertise, we can quickly identify the source of the problem and implement a solution that is unique to your business.

  • Convenient Service: Your time is valuable to us. Comfort Union understands that you lead a busy life and offers flexible scheduling choices to help you get our services when it’s most convenient for you.

  • Comprehensive HVAC Solutions: Water heaters are just one part of the HVAC system that we offer comprehensive solutions for. Comfort Union is a one-stop shop for all things HVAC, whether you need regular maintenance, emergency repairs, or a system overhaul. Since we take a comprehensive approach, we can service all of your HVAC systems with the same high standard of care.

  • Proactive Preventative Maintenance: We are firm believers in avoiding issues before they even begin through proactive preventative maintenance. Your Navien tankless water heater can last longer and run more efficiently with the help of Comfort Union’s individualized maintenance programs, which include inspections and tune-ups at regular intervals.

  • Outstanding Customer Support: Comfort Union’s commitment to openness and communication is fundamental to our mission of providing exceptional customer service. We make sure you know all there is to know about the service, from the specifics of any problems to our honest assessments of them and suggestions for how to fix them.

  • Use of Genuine Navien Parts: When replacing parts, we always use authentic Navien products to guarantee optimal performance and uphold warranty standards. Your system will continue to work consistently and smoothly thanks to our dedication to quality.

If you are interested in learning more about the HVAC systems that we install, repair, and maintain, including air conditioners, furnaces, water heaters, and more, contact us now.

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