Navien NPE-A / NPE-S Code E046
Limit control fault. A fault in the limit control — one of the safety devices that stops the unit when a measured value goes out of bounds. Navien gives owners no diagnostic step at all for this code: the instruction in the manual is to contact technical support.
Call a proThe verdict
Call a licensed plumber
Navien's own answer is "call us", which is unusually direct and worth respecting — this is a safety control on a gas appliance.
Typical cost: $150–$700
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-A / NPE-S — not averaged across the brand.
Source: Navien NPE Operation Manual (NPE-A / NPE-S) (p. 16), 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.
- Leave the unit off rather than cycling power to clear it.
- Contact a licensed professional or Navien technical support, which is the manual's own instruction for this code.
Code E046 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: