Navien tankless water heater code E441
Hot water inlet thermistor 2: open or short circuit. Code E441 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 E441 means on each Navien series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NPE-2 | Hot water inlet thermistor 2: open or short circuit | Part replacement | $150–$450 |
| NPE-A / NPE-S | Hot water inlet thermistor 2: open or short circuit | Part replacement | $150–$450 |
Each row opens the full page for that generation. We hold manuals for NPE-2 and NPE-A / NPE-S, and each one gets its own reading of code E441 — what Navien documents, what you can safely check yourself, and what the repair should cost.
What each manual actually says
The table above compares 2 series in four columns, which is enough to route you and not enough to explain anything. This is the Navien wording behind each row, one entry per manual, so you can see where the 2 readings of code E441 agree and where they part company.
NPE-2 — Hot water inlet thermistor 2: open or short circuit
A sensor on the hot water inlet side has an open or shorted circuit. On a recirculating installation that is the side where water returning from the loop comes back in, which is how the unit decides whether the loop needs reheating. Navien's instruction is to contact technical support.
NPE-A / NPE-S — Hot water inlet thermistor 2: open or short circuit
Another temperature sensor reporting an open or short circuit, this one on the hot water inlet side. Navien numbers each sensor position separately, which is genuinely useful: the code tells a technician which sensor to go to before opening anything.
Does it matter which Navien you have?
NPE-2 and NPE-A / NPE-S all route code E441 the same way: a replacement part, at $150–$450. That makes it one of the Navien numbers you can act on before working out which unit you own.
Which Navien do you have?
On the 2 series that report code E441, the model number on the rating label starts NPE — match yours against the 13 listed below. You can also 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 E441
Code E441 on these 2 Navien series points at 1 part and 1 symptom, each named by the manufacturer's own procedure for this code.