Navien error code E110
Abnormal air pressure. Code E110 means the same thing on all 2 Navien series documented here — but the fix, and what it costs, is still worth reading for your exact unit.
What code E110 means on each Navien series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NPE-2 | Abnormal air pressure | Call a pro | $0–$900 |
| NPE-A / NPE-S | Abnormal air pressure | Call a pro | $0–$900 |
Each series links to the full page: what the manufacturer's manual says for that generation, what you can safely check yourself, and what the repair should cost.
How much the answer changes between series
Every Navien series that documents code E110 routes it the same way: a professional. That is unusual enough to be worth saying, because on this brand the same number often means different work on different generations. Here it does not — so you can act on this page without first establishing which unit you own.
The cost is documented the same way across all 2 series: $0–$900, depending on which of the manufacturer's causes turns out to be yours.
What to check first, whatever your series
These checks are on the manufacturer's list for every Navien series that reports code E110, so they are safe to work through before you have identified your exact unit. They also cost nothing.
- Clean the intake air filter.
If none of those explains it, go to your own series above — the remaining checks differ by generation, and that is the whole reason this page exists.
Which Navien do you have?
The model number is on the rating label on the unit itself. Match it against the list below — or use the full model-number decoder.
Where this comes from
Source: Navien NPE-2 User's Information Manual (p. 17), read Aug 2026 — the manufacturer's own documentation for this Navien range.
Source: Navien NPE Operation Manual (NPE-A / NPE-S) (p. 16), read Aug 2026 — the manufacturer's own documentation for this Navien range.
Parts, guides and symptoms behind code E110
Everything the 2 Navien series point at for this code, in one list. A part named here is one the manufacturer's own procedure reaches for.