Navien Tankless Water Heater How to & Troubleshooting Guide

If you are looking for a tankless water heater that can provide you with hot water 24/7, Navien water heater is the way to go. This on-demand water heater has a lower carbon footprint, is energy efficient, and has a longer lifespan.

This comprehensive guide helps to make the operation and repair of your heater easier.

Why am I not getting hot water from my Navien tankless water heater?

The issue is most likely, the flow sensor inside the unit is not spinning correctly. First, open and close the pressure relief valve, which is located near the unit’s outlet. This may temporarily help to remedy the issue.

If the issue persists, contact your original installer or an NSS to service the sensor.

Navien flow sensor problems           

Older Navien heater models are prone to flow sensor issues. This is because the sensors are corroded over time which causes them to shut the heater down. To remedy this, you can take the two clamps off the sensor, pull it out and clean it. However, this is only a temporary fix.

Using a corrosion-free flow sensor made of stainless steel is a better option. Additionally, you can install a 5-micron filter in the water inlet right before the heater to remove impurities from the water. 

How do I reset my Navien tankless water heater?

  • Locate the reset button on the heater’s front control panel.
  • It is located on the lowest corner opposite the on and off button.
  • Press the reset button to reset your device.

Navien tankless water heater error codes, their meaning, and fixes

Below are different Navien water heater error codes and their solutions;

Error Code E003

Navien error code 003 how to fix indicates that there is an ignition failure in your unit.

Solution:

Ensure the main gas supply valve is open.

Error Code E004

False flame is detected in your device.

Solution:

Make sure the major electrical cord is grounded correctly.

Error Code E012

Flame loss.

Solution:

Remove the intake filter and properly wash it using a brush beneath running water. Turn off the power before removing the filter. Allow it to dry for some time before fixing it again.

Also, check if the electrical cord is grounded correctly or not.

Error Code E016

The heat exchanger is overheated.

Solution:

Shut off the appliance for half an hour and then restart. Examine and clean the filter in a cold water inlet. You also have to flush the heat exchanger.

Error Code E030

The exhaust is overheating. The heater turns off automatically when the flue pipe surpasses 149 degrees Fahrenheit.

Solution:

Turn off the device for 30 minutes and then restart it.

Remove the inlet filter and wash it under the running water with the help of a brush.

Read the user’s Navien nr-240a manual to get information on how to flush the heat exchanger and reset the remote for Navien tankless water heater.

Error Code E046

There is something wrong with limit control.

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E047

The exhaust thermostat is malfunctioning.

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E060

The Dual venturi is defective.

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E109

It provides information about the problem with the fan motor.

Solution:

Examine and wash the intake air filter underneath running water using a toothbrush. Allow it to dry and then fix it back.

Error Code E110

The air pressure is off.

Solution:

Make sure the exhaust pipe is not obstructed. Next, check and remove the intake filter from the heater. Wash it under the water with a brush, let it dry, and then place it back.

Error Code E127

It means that there is an issue with the air pressure sensor. It is caused by an open or shorted air pressure sensor.

Solution:

Turn off the device and examine the APS’s condition. Then, read the manual on Navien tankless water heater how to reset. If the problem persists after reset, replace the APS as soon as possible.

Error Code E205

The heating supply thermistor is defective. It could be open or shorted.

Solution:

Examine the thermistor’s condition and pump wiring connectors.

Error Code E218

It shows that the heating return thermistor is not working correctly. An open or short thermistor can be the root cause of this problem.

Solution:

Check the thermistor’s condition along with pump wiring connectors.

Error Code E302

Low water pressure.

Solution:

Inspect the water feeder valve, water pressure, and water pressure relief valve. If necessary, replace them all. 

Error Code E352

This number indicates that the water pressure is high.

Solution:

If your system displays this code, you need to confirm the water pressure is within good ranges. Also, check the feeder valve and pressure relief valve’s activity.

Error Code E353

It means there is some issue with a water pressure sensor. It can occur due to an open or short sensor.

Solution:

Examine and confirm the pressure sensor and wiring are in good condition. Make sure there are no loose connections. You can replace the sensor if needed. 

Error Code E407

It is an indication that your warm water outlet thermistor has some problems. It usually occurs due to an open or shorted sensor.

Solution:

Examine the wiring and thermistor’s condition. Change the thermistor if needed.

Error Code E421

The cold water inlet one thermistor is defective. 

Solution:

Confirm the thermistor and wiring is in good condition. You can change the cold water inlet thermistor if necessary.

Error Code E432

It is a visible sign that your device’s cold water inlet two thermistor is having some issues.

Solution:

Check the wiring and cold water inlet two thermistors and make sure both are in good condition. If required, replace the thermistor.

Error Code E434

It shows that the water adjustment valve is not operating properly.

Solution:

Turn off the unit and check the valve’s wiring and condition. You can contact a plumber if necessary.

Error Code E438

It means the circulation pump is not working correctly.

Solution:

Ensure all return and supply lines are open and check the 2-way valve’s direction.

Error Code E439

It tells you about the improper operation of the flow sensor.

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E441 And E445

The error code E441 informs about the open thermistor or short circuit problem. The error code E445 tells about the defect of the bypass mixing valve.

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E480

It tells you about the abnormality of the external tank thermistor. For example, an open or shorted sensor causes this issue.

Solution:

You have to inspect the sensor’s connectors to confirm they are not wet and fixed correctly. Then, you can change the tank thermistor if needed.

Error Code E515

Unusual operation of the PCB.

Solution:

Make sure the electrical cord is grounded.

Error Code E517

The DIP switch setting has some problems.

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E593 and E615

There is some issue with the front panel key. The E615 tells you about the irregularity in input and memory.

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E736 and E740

The error code E736 informs about the issue in cascade communication, and error code E740 indicates that the outdoor temperature sensor is not working correctly.

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E760 And E782:

The E760 informs you that it’s time to flush your heater. Besides, the E782 indicates that there is something wrong with the main panel communication. 

Solution:

Get in touch with Navien technical support or a professional heater repairman.

Error Code E783:

It means there is some issue with the OT-remote controller’s operation.

Solution:

Examine the controller’s condition and replace it if required.

Error Code E785

It means there is some issue with the flow sensor or switch.

Solution:

Get in touch with Navien technical support at 800-519-8794.

Error Code E787

This error informs you there is something wrong while you reset the unit.

Solution:

Turn off the device for half an hour and confirm everything is working correctly. Then, turn it on again. If the problem persists, call a technician to fix the unit.

Common Issues of Navien Tankless Heaters

here are some problems that you may have to deal with in the future or have experienced already primarily found in older Navien heater models;

Heat Exchanger Cracking

Though not a common occurrence, it is still essential to know how to identify these issues. When the heat exchanger starts to crack, it creates a gap that can escape toxic exhaust gasses. Unfortunately, the heat exchanger cannot be fixed and has to be replaced. Check to see if the warranty is still valid and contact the manufacturer.

Motherboard or Control Board Failure

This issue is more common in older heater models. This is because the motherboard or control board is the unit’s “brain” responsible for receiving and transmitting information in the heater. Therefore, when it malfunctions, it is a sign that the heater has another major underlying issue.

The main sign of motherboard or control board failure is intermittent switching off and on. Another sign is the error code display. For example, you will see Navien error code 003 on the display screen, which means the igniter is malfunctioning.

To remedy this issue, turn off the heater for some time and restart it. If the problem does not get resolved, replace the motherboard or control board or hire a professional t do it.

Navien flow sensor problems            

Older Navien heater models are prone to flow sensor issues. This is because the sensors are corroded over time which causes them to shut the heater down. To remedy this, you can take the two clamps off the sensor, pull it out and clean it. However, this is only a temporary fix.

Using a corrosion-free flow sensor made of stainless steel is a better option. Additionally, you can install a 5-micron filter in the water inlet right before the heater to remove impurities from the water. 

Why is my Navien water heater so noisy

Here are the leading causes of strange noises coming from your heater;

  • A loose part causing unnecessary vibrations
  • Vacuum in the water lines causing vibrations
  • Defective pressure valve
  • A dirty flow sensor leading to gas flow interference and producing weird noises

Hire a professional or installer to repair your heater to avoid damaging the heater and voiding your warranty.

Navien water heater with the recirculating pump not working

Ensure the recirculation pump was installed correctly. And the heater has been set to recirculation mode.  Refer to the user manual to locate the Hot Button and then press it to activate hot water recirculation.

If you are unsure of whether the recirculation pump was correctly installed, contact Navien technical center or the NSS agent who installed the heater.

How to clean a Navien tankless water heater

Follow the steps below to clean your Navien water heater;

  • Turn the power off the unit.
  • Then turn the water off.
  • Take the cover off the heater.
  • Unplug the power to your Navien water heater.
  • Remove and clean the cold air intake filter.
  • Then re-insert the filter and screw it back in place.
  • Close the cold and hot water inlet valves and then drain the water heater. Next, hook hoses to the valves, then open them to drain the water.
  • Once the tank is thoroughly drained, clean the base of the heater.
  • Then remove the cold water filter off located next to the cold water isolation valve.
  • Place a bucket underneath it to catch any water that drains when you remove the filter.
  • Then clean the filter and replace it.
  • Next, clean the “dirt-trap.” Start by removing it from the heater so you can clean it properly.
  • Then descale a flush the heater following the steps listed below.
  • Reassemble the heater and turn on the hot and cold water valves.
  • Turn on the water.
  • Then replace the heater cover and turn the gas or power back on.
  • Finally, press the power button.

Note: If you are unsure of your ability to handle this task, hire a professional to clean the heater.

How to descale a Navien tankless water heater

You need to run white vinegar through the system, to descale the water heater.

  • Pour two gallons of white vinegar into a 5gallons bucket.
  • Get a sump pump and connect the cold service hose to the sump pump.
  • Set the pump in the bucket and plug it in. Make sure that the drain hose will empty the scaling solution into the bucket.
  • Pump the white vinegar into the cold side, up through your water heater, and out the hot side.
  • The large valves should be in the “off” position, whereas the service valves should be in the “on” place.
  • Let the vinegar cycle through the cold side for 45 minutes.

How to flush out a Navien tankless water heater

  • Start by turning off the service valves and removing the hoses.
  • Connect a regular garden hose to the hot side service valve. For example, you may damp it into a bathtub, pushing the water through the isolation side on hot.
  • Open the service port on the host side and the isolation valve on the cold side, pushing water through the system. It should come out of the hot water port.
  • Flush the vinegar out of your water heaters.

Navien tankless water heater not staying hot

Here are some of the leading causes of cold water production;

  • Too many hot water users at once

Which means there isn’t enough time for the water to heat up. Create a chart to regulate hot water usage. Or invest in a larger water heater.

  • Low gas supply which prevents proper heating of water

This happens when you have a huge heater and lower gas output. To remedy the issue, consider increasing the gas supply to the heater. This may require chasing the supply lines.

  • Damaged flow sensor preventing proper supply of gas to the heater

Get in touch with Navien technical support or a professional heater repairman to fix the issue.

Navien tankless water heater not staying lit

The leading causes of the intermittent flame;

  • Clogged air vent
  • Damaged gas valve
  • Gas supply interruption
  • Dirty burners
  • Damaged flow sensor

You can fix these issues by maintaining and cleaning the heater. If this does not work, hire a professional to repair or replace any damaged parts.

Navien tankless water heater not circulating

Check to see if the water valves are open. Then check to see if the plumbing lines and the heater’s water lines are clogged. Also, check the filters to see if they are clean.

Navien tankless water heater keeps tripping the breaker

Several issues can cause this;

  • Circuit overload
  • Ground fault surges
  • Worn out the circuit breaker
  • Faulty breaker thermostat
  • Faulty wiring
  • Water leaking onto the wiring

While you may have a general understanding of the listed electrical issue above, you should not attempt to handle any electrical work unless you are a licensed electrician. Therefore, the only task you can attempt on this list is the gasket replacement for the leaking water connection.

Note: Remember to turn off power to the heater before replacing the gasket.

How to adjust the temperature on a Navien tankless water heater

The water heater is set to 120 °F (49 °C) by default. To change the water temperature;

  • Ensure that all hot water faucets are closed, and ensure that the internal circulator and any external circulating pumps are off.
  • Press the + (Up) or – (Down) buttons until the desired temperature appears on display. You can adjust the temperature while the display is flashing.
  • Once the display stops flashing, the temperature setting is stored.

Note:

  • If a hot water faucet is open, you can adjust the temperature only from 98-110 °F (37-43 °C).
  • The water heater will retain your settings during a power outage.
  • You can adjust the temperature by the below 10-degree increments, depending on the temperature range:
  • 98 °F-120 °F/ 36 °C-50 °C 1 °F or 0.5 °C increments
  • 120 °F-140 °F /50 °C-60 °C Press for 2 seconds to adjust in 5 °F or 2°C increments
  • The water heater will not provide hot water instantly.

Check this too: Richmond Water Heater How to & Troubleshooting Guide

How to clean the filter on a Navien tankless water heater

  • Press the Power button on the front panel to turn off the water heater.
  • Disconnect the power supply to the water heater.
  • Remove the front cover of the water heater.
  • Remove the screw that secures the air intake filter and then remove the filter. The filter is located at the top left of the water heater.
  • Pull the filter out of the water heater.
  • Remove the filter from the plastic assembly and clean it with a toothbrush, and clean running water.
  • Allow the filter to dry completely.
  • Reinsert the filter into the plastic assembly.
  • Place the filter assembly back into the water heater and secure it with the screw.
  • Replace the front cover.
  • Reconnect the power supply to the water heater.
  • Press the Power button on the front panel to turn on the water heater.

How to size a Navien tankless water heater

First, you need to consider Things to consider when sizing the busiest usage period or peak time. This can be determined based on the following factors:

  • Size of the household
  • The number of bathrooms, tubs, dishwashers, and washers. As well as any future additions
  • Number of residents and bathing patterns
  • Usage of household gadgets that require hot water

The average water usage for different hot water uses are as follows;

  • Around 20 gallons for a shower or bath
  • Showers – 2.5-3 gal/min
  • Automatic dishwasher – 14 gallons or 1.5 GPM
  • Washing machine – 32 gallons to wash the clothes or 2 GPM
  • Kitchen sink – 1.5 GPM
  • Shaving – 2 gallons of hot water

Check this too: Insinkerator Hot Water Dispenser How-to & Troubleshooting Guide

Calculating water heater tank size

To calculate the size of the heater, you will need to add up the amount of water required at a particular time. For example, if you have a person showering and another individual shaving. At the same time, someone is in the kitchen doing the dishes.

The total amount of water needed is 2 gallons + 1.5 gallons + (3 gallons * length of shower). Therefore, the total peak demand of hot water needed is the ideal size of the heater you should get. Fortunately, Navien water heaters recycle hot water and always provide hot water.

How much power does a Navien tankless water heater consume?

This depends on how long you leave it on and how often you use it. However, the unit comes equipped with a standard 120V appliance cord and operates between 200 and 300 watts. The average electric tankless water heater needs at least 120 amps to work.

The estimated annual operating cost of the Navien tankless water heater, based on the yearly estimated residential use per US Energy Department test criteria, is $191.

Oscar

In his spare time, Oscar loves tinkering with electronics. Solar panels, wiring, old TVs and sometimes DIY powerwalls. When he is not busy trying not to electrocute himself, you can find him in the garden tending to his vegetables and chickens.

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