Your Navien water heater may keep shutting off due to issues like insufficient gas supply, a faulty venting system, or a malfunctioning sensor, which can trigger safety features to prevent overheating or gas leaks.
A Navien water heater shutting off unexpectedly can disrupt your hot water supply and indicate underlying issues. Common causes include gas supply problems, venting restrictions, sensor malfunctions, or system overloads. This guide explores troubleshooting steps and solutions to keep your unit running smoothly.
Common Causes of Navien Water Heater Shutdowns
1. Gas Supply Issues
Insufficient gas pressure or interrupted supply triggers safety shutdowns. Symptoms include:
- Frequent error codes (E003, E110)
- Flame failure messages
- Short cycling (rapid on/off operation)
Check these gas-related components:
| Component | Check |
|---|---|
| Gas valve | Ensure full open position |
| Meter capacity | Verify adequate BTU rating |
| Pipe sizing | Confirm proper diameter for run length |
For gas line requirements, see our guide on proper gas line sizing for water heaters.
2. Venting Problems
Restricted venting causes combustion issues and shutdowns. Navien units require:
- 2″ or 3″ PVC/CPVC vent pipes
- Maximum 75 feet for 2″ pipe (with elbow deductions)
- Clearance from obstructions
Common venting mistakes:
- Too many elbows reducing effective length
- Improper slope (minimum 1/4″ per foot)
- Blocked termination cap
3. Faulty Sensors
Navien uses multiple sensors for safe operation:
- Flow sensor – Detects water movement
- Temperature sensors – Monitor heat levels
- Flame sensor – Verifies burner operation
Corroded sensors often cause false shutdowns. For similar sensor issues in other systems, see our propane heater troubleshooting guide.
Error Code Troubleshooting
Critical Error Codes
| Code | Meaning | Solution |
|---|---|---|
| E003 | Ignition failure | Check gas supply, igniter |
| E110 | Flame loss | Inspect burner, gas pressure |
| E760 | Descaling needed | Flush system |
Maintenance-Related Codes
Regular maintenance prevents many shutdowns:
- Annual flushing – Removes mineral buildup
- Filter cleaning – Every 6 months
- Vent inspection – Check for blockages
For proper descaling procedures, Navien recommends using approved cleaning solutions.
Advanced Troubleshooting
Water Pressure Issues
Improper water pressure causes flow sensor errors:
- Minimum pressure: 20 PSI
- Maximum pressure: 150 PSI
- Ideal range: 50-80 PSI
Install a pressure regulator if needed. For pressure-related solutions, see our guide on increasing water pressure with tankless units.
Recirculation System Problems
Navien’s ComfortFlow® system may cause issues if:
- Buffer tank fails
- Recirculation pump malfunctions
- Check valve sticks
When to Call a Professional
Contact Navien-certified technicians for:
- Gas valve replacements
- Heat exchanger issues
- Control board failures
- Warranty-covered repairs
For complex installations, refer to Navien’s technical specifications or consult a professional.
Preventative Maintenance Tips
- Install whole-house water filter
- Monitor system pressure monthly
- Schedule annual professional inspection
- Keep area around unit clear
