Understanding Error Codes - Navien NPE-24AWE User's Information Manual

4.2 Understanding Error Codes

When an error code appears on the front panel, refer to the following chart for a definition and possible remedy for the situation.
Auto reset Reason
E003 Ignition failure
E004 False flame detection
E012 Flame loss
E016 Heat exchanger overheat
E030 Abnormal exhaust temperature
E046 Abnormal operation: heat exchanger overheating sensor
E047 Abnormal operation: exhaust thermostat
E060 Abnormal operation: dual venturi limit switch
E109 Abnormal operation: fan
E110 Exhaust blockage (Condensate blockage)
E127 Abnormal operation: APS
E407 Abnormal operation: hot water outlet1 thermistor
E421 Abnormal operation: cold water inlet1 thermistor
E432 Abnormal operation: cold water inlet2 thermistor
E434 Abnormal operation: water adjustment valve
E438 Abnormal operation: circulation pump
E439 Abnormal operation: flow sensor
E441 Abnormal operation: hot water outlet2 thermistor
E445 Abnormal operation: mixing valve
E515 Abnormal operation: relay feedback (PCB)
E517 Abnormal operation: dip switch setting (PCB)
E593 Abnormal operation: front panel key
E615 Abnormal operation: input and memory (MCU)
E736 Abnormal operation: cascade communication
E760 Flushing alarm
E782 Abnormal operation: main panel communication
E787 Abnormal operation: reset device
If the error code is not cleared by resetting the water heater functioning (see "3.4 Resetting the Water Heater" ) 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.
Self-diagnostic / Action
Manual reset
Auto reset
Manual reset
Manual reset
Manual reset
Auto reset
Auto reset
Auto reset
Auto reset
Manual reset
Manual reset
Manual reset
Auto reset
Auto reset
Auto reset
Auto reset
Manual reset
Manual
Auto reset
Manual reset
Auto reset
Manual reset
Manual reset
Manual reset
Auto reset
Manual reset
Auto reset
Alarm
Auto reset
Manual reset
Power reset
Troubleshooting 13