Navien NCB-700-2S+/42K Service Manual page 65

Error Code Sub Code
E517 0
E594 0
E615
E740 1
E782 0
E783 0
E787 1
E788 0
E791 0
E792 0
If the actions contained in the table above do not resolve the boiler fault, contact the Navien technical support team on 1-800-519-8794.
To assist with fault resolution, error codes are displayed on the front panel and saved on a PCB board in the boiler providing a record of
the faults and failures that occur.
IMPORTANT
To reset the boiler, either press [Reset] on the front panel or turn off the boiler's power supply and then turn it on again.
64 Troubleshooting
Function
Abnormal operation: DIP switch
setting (PCB)
Abnormal operation: EEPROM
(PCB)
Abnormal operation: Input and
memory (MCU)
Abnormal operation: Outdoor
temperature sensor
Abnormal operation: Main panel
communication
Abnormal operation: OpenTherm
remote control
Abnormal operation: Reset device
Abnormal operation: Gas type
settings
NaviCirc Vavle Open error
NaviCirc Vavle Close error
Diagnosis/Actions
Check the dip switches on the front panel and the PCB.
Check the PCB.
1. Ensure that outdoor reset curve is correctly configured.
2. Check the outdoor temperature sensor's wiring connections.
Check the PCB.