Navien Error Codes

Tankless Systems are complicated systems and this they can have some errors and electronic issues. We have put together a thorough list of Navien error codes to help you diagnose and potentially fix any issues you may have.

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Please cross reference ALL replacement parts with your Navien model.

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Navien Error Codes
CodeErrorTroubleshootSolutionReplacement Parts
E001Water is boiling in the Heat Exchanger 1. clean the inlet water strainer.
2. Check the automatic flow sensor.
3. Check the heat exchanger, remove and clean with a solution
4. Check PCB board, replace if faulty.
Solution Details 001E OR power Supply 1.Inlet Filter
2.Water Adjustment Valve
3.Flush Kit
4. PCB Part# 30008300A
5. PCB Part# 30012262A
E002 Low Water Pressure 1.Wait until water supplement is terminated. Reset Is AutomaticNone Needed
E003 Ignition Failure 1. Check to see if the main gas supply is on
2. Check that the power is on
3. Check the igniter for spark
Scenario 1
Scenario 2
Scenario 3
Flame Rod Assembly
E004 False flame detection 1. Ensure ground wire is connected
2. Check the igniter for spark
Solution Details 004E Flame Rod Assembly
E007 Hot water outlet: thermistor -open 1. Check the thermistor
2. Replace the thermistor
Solution Details 007E Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E008 Hot water outlet: thermistor -short1. Check the thermistor
2. Replace the thermistor
Solution Details 008E Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E009 Abnormal fan motor activity1. Check and clean the air filter
2. Check and clean the fan motor
3. If faulty, replace fan.
Solution Details 009E 1. Navien Fan 30008834A
2. Navien Fan 30000405A
E010 Abnormal Air Pressure 1. Check the vent pipe for obstructions
2. Check and clean the air filter
Solution Details 010ENone Needed
E011 High Water Pressure 1. Check the water pressure sensor. Automatic Reset or replace sensor. Water Pressure Sensor
E012 Flame loss 1. Check the main gas line (valve open?)
2. Check intake air pipe
3. Check the ground wire
4. Check power supply
Solution Details 012E Navien Ignition Transformer
E015 Abnormal control board 1. Check power supply
2. Check the GFI
Not Defined Navien PC Board
E016 Overheating of heat exchanger 1. Turn off the system for at least 30 minutes then restart.
2. Clean the inlet water strainer
3. Check the automatic flow adjustment valve
4. Check the heat exchanger: remove and clean with a cleaning solution
Solution Details 016E 1. Inlet Water Filter
2. Water Adjustment Valve
3. Flush Kit
E021 Cold water inlet: thermistor 1 -open 1. Check thermistor
2. Replace thermistor
Solution Details 021E Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E022 Cold water inlet: thermistor 1 -short 1. Check thermistor
2. Replace thermistor
Solution Details 022E Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E027 Abnormal activity of the air pressure sensor 1. Check the vent pipe for obstructions
2. Check and clean the air filter
3. Replace Sensor
Solution Details 027E Navien Air Pressure Sensor
E028 Water leak pipe line 1. Check pipe line.
2. Replace O ring
Reset – Manual Navien O-Ring Kit
E030 Exhaust overheat: exhaust high limit switch shuts down the unit when the flue temperature exceeds 149 F or 65C 1. Turn off the unit for at least 30 minutes then restart.
2. Clean the inlet water strainer
3. Check the automatic flow adjustment valve
4. Check the heat exchanger: remove and clean with a cleaning solution
Solution Details 030E 1. Inlet Water Filter
2. Water Adjustment Valve
3. Flush Kit
E032 Cold water inlet: thermistor 2 -open 1. Check thermistor
2. Replace thermistor
Solution Details 032E Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E033 Cold water inlet: thermistor 2 -short 1. Check thermistor
2. Replace thermistor
Solution Details 033E Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E034 Abnormal – flow adjustment valve 1. Check the flow adjustment valve Not Defined Water Adjustment Valve
1. Part 30004834B
2. Part 30008245A
E035 Abnormal activity of the gas pressure sensor 1. Check gas line Solution Details 035E Gas Pressure Flow Sensor
E036 Communication failure 1. Contact Navien tech support Not DefinedNone Needed
E037 Water leak inside unit 1. Close cold water main
2. Replace leaking part/O-Ring
Solution Details 037E Navien O-Ring Kit
E038 Abnormal circulation pump 1. Check the circulation pump.
2. Check the water flow sensor
3. Check the cold water main
Not Defined Navien Circulation Pumps.
1. 30012768A
2. 30000466A
3. 30010780B
4. 30000456B
E039 Abnormal – water flow sensor 1. Check the water flow sensor 2. Replace water flow sensor Not Defined Navien flow sensor
E041 Hot water outlet: thermistor 2 -open 1. Check thermistor
2. Replace thermistor
Not Defined Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E042 Hot water outlet: thermistor 2 -short 1. Check thermistor
2. Replace thermistor
Not Defined Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E043 Abnormal cascade connection 1. Check model type 2. Check communication cable Not Defined Multi-Unit Communication Cable
E044 Abnormal thermistor connection 1. Check thermistor connection 2.Replace thermistor Not Defined Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E045 Abnormal – mixing valve 1. Check the mixing valve 2.Replace Mixing Valve 3.Check mixing valve transformer Not Defined 1. Mixing Valve Transformer
2. Mixing Valve
E046 Abnormality in limit control Not Defined Call technical support (800-519-8794) High Limit Switch
E047 Abnormality in exhaust thermostat Not Defined Call technical support (800-519-8794)Not Applicable
E048 Abnormal LPG gas pressure 1. Check the LPG gas
2. Fill the LPG gas 3. Check gas pressure flow sensor
Not Defined Gas Pressure Flow Sensor
E060 Abnormality in dual venturi 1. Reboot System 2. Replace dual venturi Call technical support (800-519-8794) 1. Dual Venturi – 30012770A
2. Dual Venturi – 30008909A
E109Abnormal operation: fan motorClean the intake air filter.1. Clean the intake air filter.
2. Reboot system 3. Replace Fan Motor
1. Navien Fan 30008834A
2. Navien Fan 30000405A
E110Abnormal air pressureNot Defined 1. Ensure that the exhaust pipe is free of obstructions.
2. Clean the intake air filter. 3. Check or replace air pressure sensor
Navien Air Pressure Sensor
E407Hot water outlet: thermistor open or short circuitNot Defined Call technical support (800-519-8794) Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E421Cold water inlet1: thermistor open or short circuitNot Defined Call technical support (800-519-8794) Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E432Cold water inlet2: thermistor open or short circuitNot Defined Call technical support (800-519-8794) Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E434Abnormal operation: water adjustment valve1. Check adjustment valve.
2. Replace valve
Call technical support (800-519-8794) Water Adjustment Valve
1. Part# 30004834B
2. Part# 30008245A
E438Abnormal operation: circulation pumpNot Defined 1. External: Ensure that all water supply and return lines are open.
2. Internal: Check the direction of the 2-way valve.
Navien Circulation Pumps.
1. Part# 30012768A
2. Part# 30000466A
3. Part# 30010780B
4. Part# 30000456B
E439Abnormal operation: flow sensorNot Defined Call technical support (800-519-8794) Gas Pressure Flow Sensor
E441Hot water inlet2: thermistor open or short circuitNot Defined Call technical support (800-519-8794) Navien Thermistor
1. Blue wire Thermistor
2. Red wire Thermistor
3. Black wire Thermistor
E445Abnormal operation: Bypass mixing valveNot Defined Call technical support (800-519-8794) 1. Mixing Valve Transformer
2. Mixing Valve
E515Abnormal operation: PCBTry new outlet Ensure that the electrical cord is properly grounded. 1. Part# 30008300A
2. Part# 30012262A
E517Abnormal operation: DIP switch settingNot Defined Call technical support (800-519-8794)Not Applicable
E593Abnormal operation: front panel keyNot Defined Call technical support (800-519-8794) Front Panel Kdc-350P
E615Abnormal operation: input and memoryNot Defined Call technical support (800-519-8794)Not Applicable
E736Abnormal operation: cascade communicationNot Defined Call technical support (800-519-8794) Multi-Unit Communication Cable
E760Flushing/service alarmNot Defined Call for flush service (647-925-1930), your installer, or purchase flush kit below. Navien Flush Kit
E782Abnormal operation: main panel communicationNot Defined Call technical support (800-519-8794)Not Applicable

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