Navien NPE-2 Code E031
Overheating of burner. The burner itself is overheating. This code exists on the NPE-2 and not on the original NPE — the older generation has no E031 at all. Navien gives owners no self-diagnostic step for it: the instruction is to contact technical support.
Call a proThe verdict
Call a licensed plumber
Navien lists no owner action for this one, and that is the right call — a burner overheating on a sealed gas appliance is not something to investigate from the outside. Turn it off and get it looked at.
Typical cost: $150–$1,400
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
Before anything else: if you smell gas, stop here, leave, and call your gas utility.
- Turn the heater off and leave it off.
- If you smell gas, leave the building and call your gas utility from outside.
- Contact your installer or Navien technical support — Navien's own instruction for this code.
Frequently asked questions
My older NPE never showed E031.
It cannot. E031 is not in the original NPE manual's code table — it was added on the NPE-2 generation. On an older unit, the same physical problem would surface as a different code, or as an overheat further downstream.