Navien NFC-175, Service Manual

Page: 70 / 138

70 NFC Service Manual
Version 1.0
Error Code Sub Code Function / Cause Self-diagnostic / Action
E110
1 Exhaust blockage (checking the FAN) 1. Check the exhaust pipe for obstructions.
2. Check and clean the intake air filter.
3. Remove exhaust pipe if possible to verify vent
blockage.
4. Check the condensate trap and drain piping for
obstruction or blockages.
2 Exhaust blockage (Using hot water)
3 Exhaust blockage (using space heating)
E205
1 Abnormal Heating supply thermistor (open)
1. Check the thermistor.
2. Check the pump connection.
2 Abnormal Heating supply thermistor (short)
E218
1 Abnormal Heating return thermistor (open)
Check the thermistor.
2 Abnormal Heating return thermistor (short)
E278
1
Abnormal operation: system supply thermistor
(open)
Check the thermistor.
2
Abnormal operation: system supply thermistor
(short)
Check the thermistor.
E279
1
Abnormal operation: system return thermistor
(open)
Check the thermistor.
2
Abnormal operation: system return thermistor
(short)
Check the thermistor.
E291 0 Supply / Return inversion limit
Check if the supply water outlet piping of heating
piping and return inlet piping are mutually changed.
E302 0 Low water pressure Check incoming water pressure and any activity at PRV.
E351 - Abnormal Auto feeder valve
1. Check auto feeder valve voltage.
2. Check direct water supply filter.
3. Check for faults with the front panel voltage.
E352 0 High water pressure
Check incoming water pressure and any activity at
PRV.
E353
1 Abnormal water pressure sensor (Open)
Check the water pressure sensor.
2 Abnormal water pressure sensor (Short)
E515
1-7 Abnormal internal communication of PCB Check the PCB.
8 Abnormal communication between PCB and Igniter
1. Check the PCB connection.
2. Check the Igniter.
9 Abnormal communication between PCB and FAN
1. Check the PCB connection.
2. Check the Fan.
10 Abnormal monitoring device of PCB 1. Check the PCB connection.
11-12
Abnormal communication between PCB and Dual
Venturi
1. Check the PCB connection.
2. Check the Dual Venturi.
E517 0 Abnormal DIP switch setting Check the DIP switch settings on the PCB.
E594 0 Abnormal operation: EEPROM Check the PCB.