Navien Tankless Water Heater Code E110

How To Fix Navien Tankless Water Heater Code E110?

Dirty or restricted air intake filter is the main culprit that causes your Navien Tankless Water Heater to throw the error code e110. Your water heater will not function unless you clean the air intake filter. 

It means you can only clear the fault code e110 from the display when you remove the blockage from that filter. Sometimes, a clogged exhaust pipe can also cause the unit to pop up the error message E110. 

In this article, I will walk you through the step-by-step cleaning procedure to clean both the exhaust pipe and the air intake filter. Also, I will describe how to reset the Navien tankless Water Heater. So, keep reading.

Table of Contents

What Does E110 Mean On Navien Tankless Water Heater?

Error code E110 on Navien Tankless Water Heater means the air pressure is abnormal. The air pressure generally goes unusual when either the exhaust pipe or the intake air filter gets clogged by dirt, debris, and lint. 

If you want to clear the error message e110 from the controller, you must keep both the exhaust pipe and the intake air filter obstruction-free. Below, I will show you how to inspect these two components for a clog and get rid of the blockage from there. 

01. Exhaust Pipe Gets Clogged

Unburned gas fumes typically go out of the unit through the exhaust pipe or venting system. You should keep the venting or exhaust pipe clean whenever it gets clogged for proper water heater operation. 

How To Fix: 

You can clean the exhausting pipe using a vacuum cleaner with an extension. Just bring the vacuum close to the vent system and suck away dirt or debris from the vent pipe as much as you can. 

Then, use a duct cleaner to reach those areas of the exhaust pipe where the vacuum cleaner fails. Alternatively, you can take apart each section of the exhaust pipe to clean the venting evenly. 

02. Dirty Air Intake Filter

Your Navien Tankless Water Heater will cease to operate if the air intake filter gets restricted by dirt and lint. And the unit will throw the error code e110 on the front display to let you know it’s time to clean the air intake filter. 

How To Fix: 

Follow the below cleaning procedure to release blockage out of the air intake filter: 

  • Press the Power button to turn the unit off.
  • Disconnect the water heater from the electric power supply.
  • Remove the front panel. 
  • Use a flat head screwdriver to unscrew the nut that holds the air intake filter into its place. 
  • Remove the filter assembly from the water heater. 
  • Pull the air filter out of the plastic assembly and remove the lint and dirt from the filter using a toothbrush. Then, rinse it with clean water. 
  • Allow the filter to dry completely. 
  • Reinsert the filter into the plastic assembly.
  • Reinstall the entire air intake filter assembly and secure it with the screw. 
  • Replace the front cover and restore the power supply to the unit.
  • Press the Power button again to turn the unit on. 

How To Reset Error Code E110 On Navien Tankless Water Heater?

Go along with the following steps to reset the error code e110: 

  • Inspect the exhaust pipe and ensure there is no blockage.
  • Check the air intake filter and clean it by removing the dirt and debris. 
  • Finally, turn the unit on and press the Back button to reset your Navien tankless water heater. It will reset the unit successfully by erasing the error code e110 from the front display. 


How do you clean a Navien condensate trap?

First off, locate the condensate trap, which you can find at the bottom of your Navien water heater. Then, pull out the metal wire click under the bottom of the cabinet and remove the cup from the bottom of the trap. Now, clean the condensate trap. 

How often do you need to flush a Navien tankless water heater?

It depends on how hard the water is. The manual suggests flushing the tankless unit once a year. However, you should flush your Navien tankless unit every six month if you live in a hard water area.

Can I use CLR to clean my tankless water heater?

Yes, you can use CLR (small amount) with diluted vinegar to flush your tankless water heater. 


Navien Tankless Water Heater will not function properly if the air intake filter gets dirty and it will alert you by popping up the error code e110. 

In short, the error code e110 indicates the air pressure is abnormal due to a clogged air intake filter. So, cleaning the air intake filter is a must to fix this issue. And fortunately, I already describe the procedure of cleaning the filter. 

So, follow the guideline, clean the air intake filter, and erase the error code e110 from the front panel display. Good Luck!

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  1. Eric, we woke to our Navien with the 110 error code and its 10 degrees! Thanks to your expertise i was able to determine that there was a bees nest in the air intake! I quickly cleared that out and all is well. THANK YOU!

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