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Navien Error Code E110: Abnormal air pressure (Tankless)

Updated · by Aurora Star Tech Inc.

Navien error code E110 on a tankless water heater means: Abnormal air pressure. It is also called Navien diagnostic code E110.

High severityTankless Water HeaterNavien NPE-2

Homeowner? What Navien code E110 means for you

Call a technician Your tankless water heater is reporting: Abnormal air pressure. The tankless water heater has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Safe things you can check yourself

  • Check that gas reaches the house: other gas appliances work, or the propane tank is not empty.
  • Make sure the heater is plugged in and its breaker is on. In winter, keep the power on: it protects the unit from freezing.
  • Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
  • Check that the hot and cold water valves under the heater are fully open.
  • If you have a remote controller, turn it off and on once. If the code comes back, call a technician.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Navien error code E110 mean?

The air pressure sensor (APS) detected a blocked or restricted air path.

Applies to: Navien NPE-A2 (built-in recirculation) and NPE-S2 condensing tankless water heaters: NPE-150S2, NPE-180A2/S2, NPE-210A2/S2, NPE-240A2/S2

Common causes of Navien code E110

  • Clogged air intake filter
  • Blocked exhaust or intake (debris, snow, ice, nests)
  • Vent run too long or too many elbows
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Navien models that use code E110

NPE-150S2NPE-180A2NPE-180S2NPE-210A2NPE-210S2NPE-240A2NPE-240S2

Other Navien Tankless codes

CodeMeaning
E031Burner overheating
E046Limit control abnormal
E047Exhaust thermistor open or shorted
E060Dual venturi abnormal
E21No hot water
E109Fan motor abnormal
E407Hot water outlet thermistor open or shorted
E421Cold water inlet 1 thermistor open or shorted
E432Cold water inlet 2 thermistor open or shorted
E434Water adjustment valve abnormal
E438Circulation pump abnormal (with air handler)
E439Flow sensor abnormal

All Navien Tankless Water Heater error codes →

Navien code E110: homeowner questions

What does Navien code E110 mean?

Abnormal air pressure. The air pressure sensor (APS) detected a blocked or restricted air path.

Is it safe to keep using my tankless water heater with code E110?

It depends on the cause. The tankless water heater has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Can I reset Navien code E110 myself?

You can try one reset (power off for 30 seconds, then on). If Navien code E110 comes back, the cause is still there and a licensed technician should check it.

Who can fix Navien code E110 near me?

Aurora Star Tech Inc. repairs Navien tankless water heaters in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Tankless Water Heater No Hot Water: What to Check

Troubleshooting guides

Source: Navien NPE-A2/S2 User's Information Manual (20049624A), 5.2 Understanding Error Codes, p.17. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency HVAC Service

647-657-2977