"Reset the unit" is the first step Navien support recommends for most issues. Three reset levels, used in sequence.
Level 1: error code reset
For any displayed error code, press the Reset button on the controller (or hold On/Off for 3 seconds, depending on controller). The unit attempts to restart and clear the fault. If transient, the unit returns to normal.
Level 2: power cycle
- Turn off the unit at the controller
- Turn off power at the breaker or unplug
- Wait 30 seconds
- Restore power
- Turn the unit back on
Used when an error code re-throws immediately after Level 1.
Level 3: factory reset
Restores all settings to factory defaults — temperature, recirculation, NaviLink pairing, language. Used when transferring the unit or when the controller behaves erratically.
Service menu required — requires installer password. Not user-accessible directly. Call Navien support or a Navien Service Specialist.
Resets that don't fix things
Three resets in a row with immediate re-throw = real underlying fault. Stop cycling. Work through the diagnostic walkthrough on the specific error code page.
When to call instead
- Reset clears code but unit immediately fails on next attempt
- Display is blank or garbled (potential PCB failure)
- Reset doesn't change the displayed code
- Combi boiler resets DHW but not heat (or vice versa) — diverter or sensor issue
Bottom line
Start with Level 1. If the code re-throws inside 60 seconds, you have a real fault — go to the specific error code page. Don't escalate to factory reset unless transferring the unit.