Navien Error Code E799: Leak detected (sensor)
How to Fix Navien Code E799
- Step 1: Check around the outside of the unit for any obvious signs of water leakage. Look at the pipe connections and the floor around the unit.
- Step 2: Ensure the unit's condensate drain line is properly connected and not blocked. A clogged drain can cause water to back up.
- Step 3: If you see any significant amount of water or can't identify the source, contact a qualified HVAC technician to diagnose and repair the leak.
What Does Navien Error Code E799 Mean?
The Navien E799 error code indicates that the unit's leak detection sensor has been triggered. Navien tankless water heaters have sensors designed to detect moisture in areas where it shouldn't be, like inside the sealed burner compartment or around sensitive electronics. When the sensor detects water, the unit shuts down as a safety precaution to prevent further damage. This isn't necessarily a catastrophic failure, but it does mean that water is present where it shouldn't be, and the source of the leak needs to be identified and fixed. Ignoring this error could lead to corrosion, electrical damage, or even more serious component failures down the road.
Common Causes of Navien Code E799
- Internal leak within the heat exchanger.
- Loose plumbing connections inside the unit.
- Condensation buildup due to poor venting or excessive humidity.
- Faulty leak detection sensor.
- Damaged or leaking internal components like pumps or valves.
Applicable Navien Models
Source Documentation
This error code is documented in 1 official Navien technical manual.
Need a Pro to Fix Navien Code E799?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →