Can I fix Navien code E110 myself?

Start with these safe checks: Make sure the exhaust pipe termination outside is free of obstructions like snow, ice, leaves or nests. Clean the intake air filter. If it continues, contact Navien technical support.

When should I call a technician for code E110?

If it continues, contact Navien technical support. Smell gas? Leave right away, don't touch light switches or phones inside, and call your gas utility or 911 from outside. Never open a gas valve, burner, gas line, vent or flue connection, or bypass a safety switch. Repeated lockouts, scorching, soot, or a CO alarm mean shut it off and call a licensed gas technician.

Navien Tankless Water Heater Error Code E110: Abnormal air pressure

What E110 means

Abnormal air pressure, often from a blocked exhaust or a dirty intake filter.

Likely causes

Blocked exhaust pipe
Dirty intake air filter

Safe first checks

Make sure the exhaust pipe termination outside is free of obstructions like snow, ice, leaves or nests.
Clean the intake air filter.

When to stop

If it continues, contact Navien technical support.

Checked against: Navien NPE-2 user's information manual: understanding error codes. Codes can differ by model and year, so confirm with your owner's manual.