If your Navien is leaking water, check for loose connections, damaged pipes, or a faulty heat exchanger, and consider contacting a professional for repairs.
Navien tankless water heaters are known for efficiency, but water leaks can signal serious issues. Brown oily fluid, pressure drops, or excessive condensate often point to internal failures requiring immediate attention.
Common Causes of Navien Water Leaks
Exhaust Leak Backflow
Many Navien units develop exhaust leaks into the cabinet after 5-6 years. This causes:
- Brown oily residue on heat exchangers
- Corrosion on internal components
- Condensation buildup inside unit
As noted in HeatingHelp forum discussions, this design flaw can lead to CO risks and premature system failure.
Faulty Heat Exchanger
A cracked heat exchanger may leak water into the combustion chamber. Warning signs include:
- Pressure drops without visible leaks
- Continuous condensate line drainage
- Steam or moisture around burner area
Improper Venting
Incorrect vent installation causes:
| Issue | Result |
|---|---|
| Intake too close to exhaust | Exhaust gas recirculation |
| Vent pipe gaps | Condensate leaks |
Diagnosing Your Navien Leak
Pressure Test Method
Isolate the boiler by closing flush valves. Monitor pressure gauges:
- System holds pressure = external leak
- Boiler loses pressure = internal leak
Condensate Line Check
Excessive drainage indicates:
- Heat exchanger failure (if dripping when off)
- Normal operation (if only during use)
Compare to professional leak detection tools for accurate diagnosis.
Repair Options
Immediate Actions
For active leaks:
- Shut off water supply
- Check pressure relief valve
- Inspect all visible connections
Professional Repairs
Complex issues require:
- Heat exchanger replacement
- Vent system redesign
- Control board inspection
Consider HVAC specialist tools for proper servicing.
Preventing Future Leaks
Maintenance Schedule
- Annual descaling
- Biannual vent inspection
- Pressure checks monthly
Installation Best Practices
- Minimum 12″ vent separation
- Proper slope on condensate lines
- Correct gas pressure settings
Note: Navien has issued multiple recalls for leaking units. Always check serial numbers against current manufacturer notices.
