Navien NPE-2 Code E441
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.
Part replacementThe verdict
Replace a part
A sensor fault: inexpensive part, service call around it. On a unit with recirculation, expect the loop to behave oddly until it is fixed — the heater is missing the reading it uses to decide when to run.
Typical cost: $150–$450
US estimate for parts and labor. Prices vary by region and by who does the work — see how we estimate costs.
What the manual says
The meaning above is transcribed from the manufacturer's diagnostic documentation for the NPE-2 — not averaged across the brand.
Source: Navien NPE-2 User's Information Manual (p. 17), read Aug 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
- Note whether you have a recirculation loop, and whether it has been behaving differently.
- Contact your installer or Navien technical support.
Frequently asked questions
Why is it numbered 2 when there is no E440?
Navien's numbering is not sequential by position — the numbers identify the fault, not the order of the parts. There are several thermistors in an NPE and each has its own code: E407, E421, E432 and E441.
Code E441 on other Navien series
The same code number can mean something different on another series — make sure you're reading the page for your exact unit:
Don't confuse this with
3 other Navien NPE-2 codes point at a thermistor too. They are different components in different places, and ordering a part against the wrong one is the most common way this fault gets expensive: