Navien Error Code E515: Low Water Flow
Warning: Your Navien boiler has detected a low water flow issue, which could lead to system damage if not addressed.
How to Fix Navien Code E515
- Check your water supply pressure. It should be between 20-80 PSI. If it's too low, you may need to contact your water supplier.
- If you have recently installed a water softener or filter, ensure it's not causing a restriction in water flow.
- Contact a professional HVAC technician if you're unable to resolve the issue.
How to Reset Navien Code E515
- Turn off the unit using the power button on the front panel.
- Turn off the gas supply valve.
- Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
- Restore power at the breaker, then open the gas valve.
- Turn the unit back on. If the error returns, the underlying issue needs repair.
Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.
What Does Navien Error Code E515 Mean?
The E515 error on your Navien boiler indicates that the water flow rate is lower than normal. This could be due to a partial blockage in the system, a faulty flow sensor, or an issue with your water supply. It's important to address this issue promptly to prevent potential damage to your boiler.
Common Causes
- Partial blockage in the system, such as scale or sediment buildup
- Faulty water flow sensor
- Issue with your water supply, such as low water pressure
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Boiler is not heating | Water flow rate at the boiler inlet | At least 5 GPM (gallons per minute) |
| Water flow rate is low | Water pressure at the boiler inlet | Between 20-80 PSI |
Applicable Navien Models
Source Documentation
Referenced in 6 official Navien technical manuals.
| Manual | Page | Reason | Action |
|---|---|---|---|
| NFB-H Installation & Operation Manual | 116 | Abnormal PCB | Check PCB connections. |
| Navien NCB-H Installation & Operation Manual | 130 | Abnormal PCB | ● Ensure that the electrical cord is properly grounded. ● Reset the boiler from the front panel. |
| Navien NFB-H Installation & Operation Manual | 116 | Abnormal PCB | Check PCB connections. |
| Navien NFC-H Installation & Operation Manual | 127 | Abnormal operation: PCB component | Manual RESET Alarm |
| Navien NHB-H Installation & Operation Manual | 119 | Abnormal PCB | Check PCB connections. |
| Navien NPF Installation & Operation Manual | 127 | Abnormal WD-PSS1 status | This error occurs when there is abnormal operation in the main controller (PCB). ● If this error occurs continuously, contact Technical Support at 1-800-519-8794. |
Replacement Parts
| Part | OEM Number | Est. Cost | Where to Buy |
|---|---|---|---|
| Water Flow Sensor | — | — | — |
Related Codes on Same Models
Other codes that affect the same Navien model families as E515.
| Code | Description | Severity |
|---|---|---|
| E001 | Ignition Failure | Warning |
| E003 | Abnormal Ignition | Warning |
| E004 | False Flame Detection | Warning |
| E012 | Flame Loss | Warning |
| E016 | Overheating | Warning |
| E030 | Exhaust Overheat Sensor | Warning |
| E031 | Inlet Thermistor Open/Short | Warning |
| E046 | Outlet Thermistor Open/Short | Warning |
| E047 | DHW Thermistor Open/Short | Warning |
| E060 | Fan Motor Abnormality | Warning |