Navien error code E109
Fan motor fault. Code E109 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 E109 means on each Navien series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NPE-2 | Fan motor fault | Call a pro | $0–$900 |
| NPE-A / NPE-S | Fan motor fault | 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 E109 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.
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 E109
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.