Navien Error Code E782: Internal PCB Fault
Warning: Your Navien boiler has detected an internal PCB fault. It's safe to use, but needs professional repair.
How to Fix Navien Code E782
- Turn off the boiler at the main power switch for 30 seconds, then turn it back on. If the error persists, proceed to the next step.
- Contact a licensed HVAC technician for repair. Do not attempt to open the boiler or fix the issue yourself.
How to Reset Navien Code E782
- 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 E782 Mean?
The E782 error on your Navien boiler indicates a fault with the internal Printed Circuit Board (PCB). This is the brain of your boiler, controlling its operations. The fault could be due to a software issue, a damaged component, or a problem with the PCB itself. The boiler will continue to function, but the fault needs to be addressed to prevent further issues.
Common Causes
- Software glitch on the PCB
- Damaged component on the PCB
- PCB itself is faulty
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Boiler displays E782 error | Check if the boiler is still functioning and heating correctly | Heating should be normal, but the error code should still be displayed |
| Error persists after power cycle | Inspect the PCB for any visible damage or burnt components | No visible damage or burnt components |
Applicable Navien Models
Source Documentation
Referenced in 6 official Navien technical manuals.
| Manual | Page | Reason | Action |
|---|---|---|---|
| NFB-H Installation & Operation Manual | 116 | Front Panel Communication | Check panel connections. |
| Navien NCB-H Installation & Operation Manual | 130 | Front Panel Communication | Contact technical support at 1-800-519-8794. |
| Navien NFB-H Installation & Operation Manual | 116 | Front Panel Communication | Check panel connections. |
| Navien NFC-H Installation & Operation Manual | 128 | Abnormal operation: panel communication | Alarm |
| Navien NHB-H Installation & Operation Manual | 119 | Front Panel Communication | Check panel connections. |
| Navien NPF Installation & Operation Manual | 128 | Abnormal operation: Controller-Panel communication | This error occurs when the controller and panel are not communicated properly. ● Check if the front control panel is connected to the controller properly. |
Replacement Parts
| Part | OEM Number | Est. Cost | Where to Buy |
|---|---|---|---|
| PCB Assembly | — | — | — |
Related Codes on Same Models
Other codes that affect the same Navien model families as E782.
| 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 |