Navien NPE-2 Code E046
Limit control fault. The limit control — the safety device that cuts the heater off when a temperature limit is passed — is reporting abnormally. Navien lists no owner-level check: the instruction is to contact technical support.
Call a proThe verdict
Call a licensed plumber
A safety limit device is exactly the wrong thing to work around. The component itself is usually inexpensive; what you are paying for is a technician establishing whether the limit is faulty or whether it is doing its job because something else is overheating.
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-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.
- Contact your installer or Navien technical support — Navien's own instruction for this code.
Frequently asked questions
Can a limit control just be replaced and forgotten?
Only after finding out why it tripped. A limit device that opens is often reporting a real overheat, and swapping it without answering that question removes the protection instead of the fault.
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: