Your Navien tankless water heater has been working fine till now, but suddenly the heater stopped, and the display flashed with an error code E110 along with the wrench or service symbol. Are you confused and need clarification about what it means and how to fix it? in this easy tutorial, we will explain why Navien tankless water heater show code E110 and how to solve it in a few easy steps.

error code e110 and service icon displayed on the navien tankless water heater display

Why Navien tankless water heater show code E110?

The main reason for the navien water heater to show this code is due to Abnormal Air pressure. If you look at the manufacturer error codes chart below, it is stated the same. That means the air cannot exhaust properly to the outside or suck enough air into the system.

e110 code in navien tankless water heater

Possible causes:

  • It may be caused due to blockages in the air inflow pipes or air intake filter.
  • May be caused due to the clogged or blocked exhaust pipe.

The below table consists of components and tools used in troubleshooting Error code E110 process, we also included the best buy links.

1Philips Screw Driverhttps://amzn.to/41DCRIb
2Cleaning Brushhttps://amzn.to/478As9u
33" Exhaust mesh cover (PVC)https://amzn.to/3tA8MfY
43" Exhaust mesh cover (Steel)https://amzn.to/3H26vgH

1. Air Inflow pipe and filter

One end of the air intake pipe is in the outer environment. The external environment has dust and debris flying around, which can enter the pipes. Even if we attach a bird filter, small creatures like insects, flies and bugs can enter the pipes. An air intake filter in the water heater unit blocks these external particles from entering the water heater unit. But all these particles are accumulated on the mesh filter, which causes a blockage to the airflow and causes abnormalities in burning the gas. Then the heater stops and display the error code E110.


First, check for blocks in the air intake pipe. It is recommended to inspect the outer end of the pipe first. In colder areas, snowfall can sometimes cause blockages in the intake pipe. If there are no blockages outside, the problem is likely with the air intake filter and needs to be cleaned. The steps to clean the filter are as follows:

  • Turn off the heater and unplug the power socket from the power source.
  • Remove the front panel with the help of screw driver
  • From the below image, at the inside end of the air intake pipe you can see a mesh filter fitted with a screw, Unscrew it and take the filter out.how to remove air intake filter on navien tankless water heater
  • Look for dirt and clean with a brush, you can even clean it under tap water to remove any sticky particles.
  • Dry the filter completely and fit it as it is with screw driver and put the front panel back.
  • Connect the heater to power supply and press the power button to turn it ON.
Temporary Solution: If you are in a hurry or have no time to clean the air intake pipe and filter, you can remove the front panel and reset the heater to fix the error E110. But this is temporary; you must clean the air intake pipe and filter soon.

Also read:  Do you need Expansion Tank for Tankless Water Heater

2. Clogged or blocked exhaust pipe

The exhaust pipe is an important component of the gas-based tankless water heater as it removes harmful gases like carbon monoxide emitted during combustion and vents them from entering your home. The exhaust pipe must be inspected regularly, and blockages caused by dirt, birds, or snow must be removed and cleaned to keep your navien tankless heater free from errors like E110. To make it easy add a terminal mesh protector which blocks dirt and flies at the exhaust terminal itself, we added its link in the above table please check.

exhaust pipe of tankless water heater blocked of snow cleaned

Follow the below steps to clean your exhaust pipe easily:

  • Turn off the navien tankless heater by pressing the power button and removing the power cable from the power source. Also, turn off the gas supply. 
  • First, look for any clogs on the outer end of the exhaust pipe. Clean any debris or blocks from the pipe using a brush or a vacuum cleaner.
  • If the blockage is severe and cannot be cleaned with a brush or vacuum cleaner, you need to disconnect the exhaust pipe joints, clean them more thoroughly, and fix them again.
  • Once the pipe is clear, reconnect and turn on the heater and gas supply.

Also read: Tankless water heater leaking? find and stop the leak

Reset the heater after cleaning

After completely cleaning and removing the blockages plugin the cable into power supply and turn on the heater by pressing the power button. Next to reset the tankless water heater press the back button on the front panel dashboard and wait for few seconds till the heater starts. Set the temperature to max and check for the hot water in the faucets.

If you get other errors on your navien hot water heater look into our comprehensive guide on Navien tankless water heater error codes.

If you’ve tried resetting the water heater and followed the above solutions, but still the problem persists, it’s best to reach out for professional help. You can contact a licensed technician or technical support of Navien tankless heaters at the provided phone number (1-800-519-8794) for further assistance and instructions on resolving the issue.

Frequently asked questions (FAQ):

  • How frequently code E110 comes on navien water heaters?

It depends on the outdoor air quality, if you stay in places where more amount out dirt and debris raises in air you need to clean the air filter more frequently. Generally clean the air filter between 3- 4 months to avoid getting error code E110.

Regular service maintenance of navien tankless water heaters can help you to rule out error codes. If you have any questions or concerns, don’t hesitate to leave a comment below! Our team is here to assist you and provide all the information you need. Your feedback is important to us, so please feel free to share your thoughts and we’ll respond as soon as possible.

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