Navien NPE-180A2 User's Information Manual page 18

Error Code Reason
Abnormal operation: cascade
E736
communication
Abnormal operation: outdoor
E740 temperature sensor (in case of installed
AHU)
E760 Flushing/service alarm
E762 Vent pipe not properly inserted
E773 Using the wrong gas
Abnormal operation: main panel
E782
communication
Abnormal operation: flow switch/
E785
sensor (in case of installed AHU)
Abnormal operation: Discrepancy with
E788 the gas type on the panel DIP S/W
setting and the panel
If any of these remedies do not resolve the problem, contact Technical Support at 1-800-519-8794.
18 Troubleshooting
Self-diagnostic / Action
Contact Technical Support at 1-800-519-8794.
Contact Technical Support at 1-800-519-8794.
Contact the installer to perform routine service.
Contact Technical Support at 1-800-519-8794.
Contact Technical Support at 1-800-519-8794.
Contact Technical Support at 1-800-519-8794.
Contact Technical Support at 1-800-519-8794.
Check the supplied gas type and match the gas type
setting on the panel DIP S/W and the panel.