Navien NFC-175 Service Manual page 94

Check method
Fault
110E
Exhaust blockage
Condensate drain error
Defective air supply /
exhaust flue
94 NFC Service Manual
Possible Causes
1. If 110E occurs intermittently during ignition or combustion, compare the
Abnormal flow of intake
air supply / exhaust
2. Replace the old PCB with the latest version.
Exhaust air is blocked due to condensate drain error.
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Condensate drain error
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1. Check the exterior of the flue for damage and obstructions.
Deformed or clogged
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
Exhaust gas flows in
E110.
through the supply pipe
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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.
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Blocked condensate drain
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If the air pressure sensor hose is broken or clogged.
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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.
Check the installation of the flue.
Check method
Version 1.0