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Navien E110 — Exhaust Blockage
Your Navien detected an exhaust blockage or abnormal air pressure. Something is restricting the intake or exhaust — often a blocked vent, condensate, or a dirty filter.
E110 means the unit sensed that its intake or exhaust isn't flowing the way it should — an actual blockage, or an air-pressure reading outside the normal range. Because safe combustion depends on moving the right amount of air, the unit locks out until the path is clear.
On the South Shore, the seasonal version of this is a vent termination blocked by snow, ice, leaves, or a nest. Inside, it can be condensate pooling in the vent or trap, a dirty intake filter, or an air-pressure sensor reading wrong. We work outside-in: vent termination first, then condensate, then the sensor.
What causes E110
1. Blocked vent or intake termination
Snow, ice, leaves, insects, or a bird or rodent nest at the outside termination is the classic cause — especially after a storm. Clearing it often restores the unit.
2. Condensate blockage
Condensing units make water. If it pools in the vent or the trap clogs, it restricts airflow and trips E110. We clear and check the condensate path.
3. Dirty air-intake filter
A clogged intake filter chokes airflow enough to read as abnormal pressure. Quick to check and clean.
4. Air-pressure sensor fault
If the physical path is clear, the pressure sensor itself may be misreading. We test it before replacing.
What you can safely check first
- Look at the vent termination outside and clear any snow, leaves or bird nest you can reach safely from the ground.
- One reset is reasonable after clearing an obvious blockage.
- If you smell exhaust indoors or a carbon-monoxide alarm sounds, get everyone out and call 911 or the gas utility first, then call us.
When to stop and call us
If the vent is clear and E110 returns, the condensate path or the air-pressure sensor needs a professional look. A blocked exhaust is exactly the fault that can push combustion gas where it does not belong, so it is not one to live with.
Seeing E110 on your Navien?
Book online and we will diagnose the actual cause, explain what we find, and price the repair before starting.
Navien E110 FAQs
What does Navien error code E110 mean?
E110 indicates an exhaust blockage or abnormal air pressure. The unit sensed that air is not moving through the intake or exhaust the way it should, and locked out because safe combustion depends on correct airflow.
What causes E110?
Most often a blocked vent or intake termination outside — snow, ice, leaves, or a nest — especially after a storm. It can also be condensate pooling in the vent or trap, a dirty intake filter, or a faulty air-pressure sensor.
Is E110 an emergency?
The lockout itself is protective and not usually an emergency. But a blocked exhaust is exactly the kind of thing that can push combustion gases where they don't belong — so if you smell exhaust indoors or a carbon-monoxide alarm sounds, get everyone out and call 911 or the gas utility first, then call us.
Can I clear E110 myself?
You can safely check the outside vent termination for an obvious blockage and clear snow, leaves, or a nest, then try one reset. If the vent is clear and E110 returns, the condensate path or the air-pressure sensor needs a professional look.
How much does an E110 diagnosis cost?
The $99 service fee sends a licensed technician out to diagnose the problem. Approve the repair on the spot and the fee is not charged at all; decline it and the $99 covers the visit. What the repair itself costs depends on what we find, and you get that price before any work starts rather than after.
Other codes on this unit? See all Navien error codes.
Why South Shore homeowners choose Johnson Bros.
Navien E110 diagnosed properly
We diagnose the cause rather than clearing the code and hoping. You get an upfront price before any work starts.
Not sure what's wrong? Send a photo or videoBooking online is the quickest way to hold the next open appointment. Call instead if it is urgent and you would rather talk to someone.
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Navien E110 diagnosed properly
We diagnose the cause rather than clearing the code and hoping. You get an upfront price before any work starts.
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