Navien NFC-250/175H Installation Manual page 128

Error Code Reason
E615 Abnormal operation: input and memory
E736 Abnormal operation: cascade communication
Abnormal operation: outdoor temperature sensor (appears only
E740
when the outdoor reset curve is enabled).
E761 Abnormal Operation: Pre-Heat Aquastat
E762 Abnormal flue gas duct: Vent pipe not properly inserted
E773 Using the wrong gas
E777 Abnormal operation: LWCO limit (external device)
E782 Abnormal operation: panel communication
Abnormal operation: zone controller communication
E784
(external device)
E786 Improper front panel
E788 Abnormal Gas Setting
If any of these remedies do not resolve the problem, contact Technical Support at 1-800-519-8794.
128 Operating the Boiler
Self-diagnostic/Action
Manual RESET
Auto RESET
Alarm
Alarm
Alarm
Alarm
Auto RESET
Parameter RESET
Auto RESET
Alarm
Alarm
Alarm
Manual RESET
(Start-up Wizard )