Navien Fault Codes

Welcome to the fault-codes section of this site. The following table or page contains the information required to help repair and diagnose the fault codes being shown on the boiler display. You may be guided through the fault finding sequence or steps, for rectifying your boiler with this fault code. Suggested repair solutions may be provided by a link to a repair page. NB Some fault codes are only applicable to a specific range of boilers only.

Error CodeError LevelClassificationFunctionDiagnosis/Actions
E0013 or 2Combustion systemCombustion systemHeat exchanger overheatingManual reset
E0033Combustion systemIgnition errorManual reset
E0042Combustion systemFalse flame detectionAuto reset
E0123Combustion systemFlame lossManual reset
E0163Combustion systemHeat exchanger overheatingManual reset
E0303Combustion systemExhaust overheat: exhaust limit switch stops the boiler when the flue temperature exceeds 110°C (230°F) for more than 10 sec.Manual reset
Auto reset
E0462Combustion systemHeat exchanger thermistor errorAuto reset
E0473
2
Combustion systemExhaust thermistor errorManual reset
E0602Combustion systemDual venturi limit switch errorAuto reset
E1093Air supply systemFan motor activity errorManual reset
E1103Air supply systemExhaust blockageManual reset
E1272
3
Air supply systemAPS error (open, short, initial value or no response)Auto reset
Manual reset
E2052CH systemH/E outlet error: thermistor open or shortAuto reset
E2181CH systemH/E inlet error: thermistor open or shortAlarm
E3022Water supply systemLow water pressure errorAuto reset
E3522Water supply systemHigh water pressure errorAuto reset
E3532Water supply systemWater pressure sensor errorAuto reset
E4071DHW systemHot water outlet 1: thermistor open or shortAlarm
E4212DHW systemCold water inlet 1: thermistor open or shortAuto reset
E5153ControllerPCB errorManual reset
E5173ControllerDIP switch setting errorManual reset
E5941ControllerPartial PCB communication errorAlarm
E6153ControllerInput and memory errorManual reset
E7402HardwareOutdoor sensor errorAuto reset
E7821HardwareMain panel communication errorAuto reset
E7831HardwareOT-remote controller errorAuto reset
E7872
3
HardwareDevice reset errorManual reset
Error CodeClassificationSub CodeFunctionDiagnosis/Actions
E001Combustion system0Heat exchanger overheating1. Clean the strainer.

2. Check voltage via PCB at the pump

3. (AC 230 V)

4. Check that the flow rate is correct

5. Check if water is circulating in the heating lines.

6. Check the heat exchanger and flush it with cleaning solution if necessary.
E003Combustion system0Ignition failure1. Check the main gas supply

2. Check if the manual gas valve is open.

3. 2. Check if the igniter is sparking.

4. 3. Tighten the ground terminals on the heat exchanger.
E004Combustion system0False flame detection1. Ensure that the ground wire is connected.

2. Check if the igniter is sparking.
E012Combustion system0Flame loss1. Check if the main gas valve is open and verify the incoming gas pressure.

2. Check the intake air filter.

3. Check the ground wire.

4. Check the power supply.

5. Tighten the ground terminals on the heat exchanger.

6. Adjust the anti-short cycle time.
E016Combustion system0Heat exchanger overheat1. Turn OFF the boiler, wait at least 30 min, and then restart the boiler.

2. Clean the inlet water filter and strainer.

3. Check the high limit switch and PCB.

4. Check the 3-way valve.

5. Check the heat exchanger and flush it if required.
E030Combustion system0Exhaust overheat: exhaust limit switch stops the boiler when the flue temperature exceeds 110°C (230°F) for more than 10 sec.1. Turn OFF the boiler, wait at least 30 min, and then restart the boiler.

2. Clean the strainer.

3. Check the heat exchanger and flush it if required.
E046Combustion system2Heat exchanger thermistor short error
Check the heat exchanger thermistor connection.
E047Combustion system1
2
Exhaust thermistor open error
Exhaust thermistor short error
Check the exhaust thermistor connection.

E060Combustion system1
2
3
Dual venturi limit switch error (ON)
Dual venturi limit switch error (Closed OFF)
Dual venturi limit switch error (Open ON)
Check the dual venturi connection.
E109Air supply system0Fan motor activity error1. Check and clean the air intake filter.

2. Check and clean the fan motor.

3. Test the voltage from the PCB to ensure that it is correct. Replace fan if PCB voltage is normal.
E110Air supply system1
2
3
Exhaust blockage (fan)
Exhaust blockage (DHW)
Exhaust blockage (space heating)
1. Check the exhaust pipe for obstructions.
2. Check and clean the intake air filter.
3. If possible, remove the exhaust pipe to ensure that the flue is clear.
E205CH system1
2
Heating supply thermistor open error
Heating supply thermistor short error
1. Check the thermistor.
2. Check pump wiring connections.
E218CH system1
2
Heating return thermistor open error
Heating return thermistor short error
Check the thermistor.

E302Water supply system0Low water pressure error1. Check the feeder valve.

2. Check the incoming water pressure and activity at the PRV.
E352Water supply system0High water pressure error1. Check the feeder valve.

2. Check the incoming water pressure and activity at the PRV.
E353Water supply system1
2
Water pressure sensor open error
Water pressure sensor short error
Check the water pressure sensor.
E407DHW system1
2
Hot water outlet thermistor open error
Hot water outlet thermistor short error
1. Check the thermistor.

2. Replace the thermistor.
E421DHW system1
2
Cold water inlet thermistor open error
Cold water inlet thermistor short error
1. Check the thermistor.

2. Replace the thermistor.
E515Controller1
8
9
10
11
13-14
PCB internal communication error
PCB to igniter communication error
PCB to fan communication error
PCB monitoring device error
PCB to dual venturi communication error
PCB to 3-way valve communication error

Check the PCB.
1. Check the PCB connection.
2. Check the igniter.

1. Check the PCB connection.
2. Check the fan.

1. Check the PCB connection.

1. Check the PCB connection.
2. Check the dual venturi.

1. Check the PCB connection.
2. Check the 3-way valve.
E517Controller0Dip switch setting error
Check the dip switches on the front panel and the PCB.
E594Controller0Partial PCB communication errorCheck the PCB.
E615Controller0
1
2
14
15-16
Heat exchanger 1, high limit switch input data error
Exhaust sensor input data error
Flame rod input data error
PCB memory error
Pressure sensor input data error Sub code 15: < the range Sub code 16: > the range

Check the PCB.

1. Check the exhaust sensor wiring connections.
2. Check the exhaust sensor.

1. Check the flame rod wiring connections.
2. Check the flame rod.

Check the PCB.

1. Check the pressure sensor wiring connections.
2. Check the pressure sensor’s output voltage.
E740Hardware1
2
Outdoor temperature sensor open error (appears only when outdoor reset is enabled).


Outdoor temperature sensor short error
(appears only when the outdoor reset is enabled).
1. Ensure that outdoor reset curve is correctly configured.

2. Check the outdoor temperature sensor’s wiring connections.
E782Hardware0Main panel communication errorCheck the PCB.

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