Troubleshooting Common Issues with Navien Tankless Water Heaters

Navien, a renowned company in the water heater industry, offers a range of cutting-edge products that have become a preferred choice for many homeowners. Navien tankless water heaters are renowned for their reliability and efficient hot water delivery, yet like any appliance, they may face issues, including inconsistent cold water temperatures.

Knowing and addressing potential problems ensures a consistent hot water supply when needed, preventing any inconvenience or discomfort. Moreover, fixing minor issues is more cost-effective than dealing with major breakdowns.

Common Navien Tankless Water Heater Problems

To keep your hot water flowing smoothly, here are some common problems in Navien tankless water heaters and how to fix them.

navien tankless water heater problems

● Error Codes

Navien tankless water heaters come equipped with built-in error codes to simplify troubleshooting. Here are a few standard error codes and their fixes:

  1. Error Code E003 – Ignition failure: Ensure the main gas supply valve is open.
  2. Error Code E004 – False flame detected: Check the electrical cord for proper grounding.
  3. Error Code E012 – Flame loss: Unplug the unit, clean the intake filter, and restart.
  4. Error Code E515 – Unusual operation of the PCB: Check the electrical cord’s grounding.
  5. Error Code E760 – Time to flush your water heater: Refer to the manual or contact a plumber.

For other codes, it’s advisable to consult a service technician.

● Cracked Heat Exchanger

A cracked heat exchanger can lead to the escape of toxic gases and is irreparable. In such cases, upgrading to a newer Navien tankless water heater is the solution.

● Control Board Failure

If your unit repeatedly shuts on and off, it may indicate control board issues. Contact professionals for evaluation and potential replacement.

● Noisy Operation

Unusual sounds from your unit could be due to loose parts, a water line vacuum, a defective pressure valve, or a dirty flow sensor. Professional assistance is recommended to address these issues, especially if the unit is under warranty.

● Recirculating Pump Issues

Ensure the heater is set to recirculation mode as per the user manual. If problems persist, consult a professional to verify the installation.

● Water Isn’t Staying Hot

Several factors can cause fluctuations in hot water delivery, including simultaneous heavy usage, low gas supply, damaged flow sensor, or a pilot light that won’t stay lit. In some cases, these issues may also result in unexpected bursts of cold water. You can consult a professional for diagnosis and repairs.

● Tripping Breaker

Suppose your Navien tankless water heater trips the breaker. In that case, it may be due to a damaged unit or water leakage into the wiring. If no leaks are found, further electrical troubleshooting is needed.

Navien Tankless Water Heater Not Heating

If your Navien tankless water heater isn’t producing hot water, the flow sensor might be the culprit. A malfunctioning flow sensor can incorrectly read the water flow, leading to sudden changes between hot and cold water. Try temporarily opening and closing the pressure relief valve near the outlet to resolve the issue.

Sensor corrosion can be a recurring problem for older models, and replacing it with a stainless steel version is recommended. Installing a water inlet filter can also help eliminate water impurities that damage the flow sensor. Consider upgrading to a newer model if problems persist with an aging unit.

Navien Tankless Water Heater Standby Mode

Navien tankless water heaters feature Standby, operational, and error modes. Standby mode, indicated by a green screen, allows the heater to await activation. It may enter standby mode if hot water demand exceeds capacity or the water temperature reaches a safety threshold.

Read also: What is the Downside of a Tankless Water Heater?

To deactivate standby mode, a simple reset is usually sufficient. This method should successfully deactivate the standby mode and restore your Navien tankless water heater.

So, how do you reset the Navien tankless water heater to deactivate the standby mode? Here’s the guide:

  • Press the Back button on the front panel.
  • Disconnect the power cord if using a GFI outlet.
  • Flip the breaker in the breaker box to the off position, wait 30 seconds, and then restore power.

Navien tankless water heaters are known for their exceptional performance but may encounter problems like any appliance. To prevent common Navien tankless water heater problems and ensure your unit operates at its best, you can do regular maintenance or ask for professional assistance.

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Heater Technician is a skilled author and water heater expert with years of experience in the field. He has authored several articles and books on various aspects of water heater installation, maintenance, and repair.