Navien NCB500-2S/37K User Manual

56 Troubleshooting
5.1 Error Code Classification
When an error code appears on the front panel, refer to the following chart for a definition and possible remedy for the situation.
Item Error Code Description Reset
Combustion
E001 Overheating of heat exchanger Manual
E003 Ignition failure Manual
E004 False flame detection Auto
E012 Flame loss Manual
E016 Heat exchanger overheat Manual
E030 Abnormal exhaust temperature Manual
E031 Overheating of Burner Manual
E046 Abnormal operation: Heat exchanger overheating sensor Auto
E047 Abnormal operation: Exhaust thermostat Manual/Auto
Air Circulation E109 Abnormal operation: Fan Manual
Central Heating
Circulation
E205 Heating supply thermistor open or short circuit Auto
E218 Heating return thermistor open or short circuit Alarm
E291 Supply/Return inversion limit Manual Reset
Water Supply
E302 Low water pressure Auto
E352 High water pressure Auto
E353 Abnormal operation: Water pressure sensor Auto
DHW Circulation
E407 DHW Outlet thermistor Open or Short Circuit Alarm
E421 DHW Inlet thermistor Open or Short Circuit Auto
E434 Abnormal operation: Flow control value Alarm
E441 DHW Outlet 2 thermistor open or short circuit Alarm
E445 Abnormal operation: Mixing valve Alarm
E480 DHW tank thermistor open or short circuit Alarm
Controller (PCB)
E515 Abnormal operation: Relay feedback (PCB) Manual
E517 Abnormal operation: DIP switch setting (PCB) Manual
E594 Abnormal operation: EEPROM (PCB) Alarm/Manual
E598 Abnormal operation: Panel real time clock Alarm
Controller (MCU) E615 Abnormal operation: Input and memory (MCU) Manual
Installation
E740 Abnormal operation: Outdoor temperature sensor Auto
E782 Abnormal operation: Main panel communication Auto
E783 Abnormal operation: OpenTherm remote control Auto
E787 Abnormal operation: Reset device Manual/Power Reset
E788 Abnormal operation: Gas type settings Manual
If the error code is not cleared by resetting the boiler functioning (see “4.4.6 Resetting the Boiler”) or if it occurs repeatedly, call the
nearest official Technical Assistance Service (TAS), indicating the number of the error code appearing on the front panel.
5. Troubleshooting

Navien NCB500-2S/37K Specifications

General

Brand	Navien
Model	NCB500-2S/37K
Category	Boiler
Language	English