Navien tankless water heater code E432
Cold water inlet thermistor 2: open or short circuit. Code E432 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 E432 means on each Navien series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NPE-2 | Cold water inlet thermistor 2: open or short circuit | Part replacement | $150–$450 |
| NPE-A / NPE-S | Cold 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 E432 — 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 E432 agree and where they part company.
NPE-2 — Cold water inlet thermistor 2: open or short circuit
The second cold water inlet sensor has an open or shorted circuit. The same class of fault as E421, on the other inlet-side sensor. Navien's instruction is to contact technical support.
NPE-A / NPE-S — Cold water inlet thermistor 2: open or short circuit
The second cold water inlet sensor is open circuit or shorted. Navien fits more than one inlet sensor and numbers the faults separately, so this is the same class of problem as E421 at a different measuring point.
Does it matter which Navien you have?
NPE-2 and NPE-A / NPE-S all route code E432 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 E432, 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 E432
Code E432 on these 2 Navien series points at 1 part and 1 symptom, each named by the manufacturer's own procedure for this code.