109
Operating the Boiler
11.7 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.
Error Code
Reason
Self-diagnostic/Action
E001
Heat exchanger over temperature
Auto reset/Manual reset/Power On reset
E003
Ignition failure
Manual reset/Power On reset
E004
False flame detection
Auto reset
E012
Flame loss
Manual reset/Power On reset
E016
Heat exchanger overheat
Manual reset/Power On reset
E030
Abnormal operation: exhaust temperature
Auto reset/Manual reset/Power On reset
E031
Burner overheating
Manual reset
E046
Abnormal operation: heat exchanger overheating sensor
Auto reset
E047
Abnormal operation: exhaust thermostat
Auto reset/Manual reset/Power On reset
E060
Abnormal operation: dual venturi
Alarm
E109
Abnormal operation: fan motor
Manual reset/Power On reset
E110
Exhaust vent closed
Manual reset/Power On reset
E127
Abnormal operation: APS
Alarm
E205
Abnormal operation: heating supply thermistor
Auto reset
E218
Abnormal operation: heating return thermistor
Alarm
E278
Abnormal operation: system supply thermistor
Alarm
E279
Abnormal operation: system return thermistor
Alarm
E291
Supply/Return inversion limit
Manual reset/Power On reset
E302
Low water pressure
Manual reset
E352
High water pressure
Auto reset
E353
Abnormal operation: water pressure sensor
Auto reset
E480
Abnormal operation: DHW tank temperature sensor
Alarm
E515
Abnormal operation: PCB component
Alarm/Manual reset/Power On reset
E517
Abnormal operation: DIP switch setting (PCB)
Manual reset/Power On reset
E594
Abnormal operation: EEPROM (PCB)
Alarm
E615
Abnormal operation: MCU
Alarm/Auto reset/Manual reset/Power On
reset
E736
Abnormal operation: Cascade communication
Alarm
E740
Abnormal operation: outdoor temperature sensor
Alarm
E765
Abnormal external-pump
Alarm
E774
Manual reset limit
Manual reset
E775
Auto reset limit
Auto reset
E777
Abnormal operation: LWCO limit (external device)
Auto reset
E782
Abnormal operation: boiler communication
Alarm
E784
Abnormal operation: zone controller communication (external device)
Alarm
If these remedies do not resolve the problem, contact Technical Support at 1-800-519-8794.
Summary of Contents for NHB Series
Page 120: ...120 Appendixes 12 6 Component Assembly Diagrams and Part Lists 12 6 1 Case Assembly NFB 301C...
Page 122: ...122 Appendixes 12 6 2 Case Assembly NFB 399C...
Page 124: ...124 Appendixes 12 6 3 Heat Exchanger and Waterway Assembly NFB 301C...
Page 126: ...126 Appendixes 12 6 4 Heat Exchanger and Waterway Assembly NFB 399C...
Page 128: ...128 Appendixes 12 6 5 Combustion Parts Assembly NFB 301C...
Page 131: ...131 Appendixes 12 6 6 Combustion Parts Assembly NFB 399C...
Page 134: ...Memo...