Navien NCB-150E Service Manual page 112

Check method
Fault
110E Abnormal flow of intake
Exhaust blockage air supply / exhaust
Condensate drain error Condensate drain error
Deformed or clogged
Defective air supply/
exhaust flue
Exhaust gas flows in
through the supply pipe
Possible Causes
1. If 110E occurs intermittently during ignition or combustion, compare the
standard RPM with the current RPM at Min / Max combustion (dip switch
1-1&1-2). If the current RPM is higher than normal, check the following:
Air supply / exhaust vent for any blockages.
●
Blocked condensate drain
●
If the air pressure sensor hose is broken or clogged.
●
2. Replace the old PCB with the latest version.
Exhaust air is blocked due to condensate drain error.
Check if the condensate hose or the siphon is frozen.
●
Check if the condensate hose is kinked.
●
Remove bottom of trap and verify it is not blocked.
●
1. Check the exterior of the flue for damage and obstructions.
flue
2. Check if rainwater is collected due to vertical installation of the air intake pipe.
If the exhaust gas enters into the air supply pipe, abnormal combustion may cause
E110.
Check the installation of the flue.
●
Check method
Troubleshooting 111