Navien Error Codes

    Tankless Systems are complicated systems that 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.

    Navien Error Codes
    CodeErrorTroubleshootSolutionReplacement Parts
    E001Water is boiling in the Heat Exchanger1. 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 Supply1. Inlet Water Filter
    2. Water Adjustment Valve NPE-A
    3. Water Adjustment Valve 30004834B
    4. Navien Flush Kit
    5.Navien CB 30000181A
    6.Navien CB 30012262A
    7.Navien CB 30008300A
    E002Low Water Pressure1.Wait until water supplement is terminated.Reset Is AutomaticNone Needed
    E003Ignition Failure1. 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    		1.Flame Rod NPE/NCB
    2.Flame Rod CR/CC/CH/NR/NP
    3.Flame Rod CR/CC/CH/NR/NP
    4.Flame Rod NPE/NCB
    E004False flame detection1. Ensure ground wire is connected
    2. Check the igniter for spark    		Solution Details 004EFlame Rod Assembly
    E007Hot water outlet: thermistor -open1. Check the thermistor
    2. Replace the thermistor    		Solution Details 007ENavien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E008Hot 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
    E009Abnormal fan motor activity1. Check and clean the air filter
    2. Check and clean the fan motor
    3. If faulty, replace fan.    		Solution Details 009E1. Navien Fan 30008834A
    2. Navien Fan 30000405A
    E010Abnormal Air Pressure1. Check the vent pipe for obstructions
    2. Check and clean the air filter    		Solution Details 010ENone Needed
    E011High Water Pressure1. Check the water pressure sensor.Automatic Reset or replace sensor.Water Pressure Sensor
    E012Flame loss1. Check the main gas line (valve open?)
    2. Check intake air pipe
    3. Check the ground wire
    4. Check power supply    		Solution Details 012E 1. Ignition Transformer – 30010455A
    2. Ignition Transformer – 30002475A
    E015Abnormal control board1. Check power supply
    2. Check the GFI    		Not Defined1. Navien CB 30000181A
    2. Navien CB 30012262A
    3. Navien CB 30008300A
    E016Overheating of heat exchanger1. 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 016E1. Inlet Water Filter
    2. Water Adjustment Valve NPE-A
    3. Water Adjustment Valve 30004834B
    4. Navien Flush Kit
    E021Cold water inlet: thermistor 1 -open1. Check thermistor
    2. Replace thermistor    		Solution Details 021ENavien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E022Cold water inlet: thermistor 1 -short1. Check thermistor
    2. Replace thermistor    		Solution Details 022ENavien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E027Abnormal activity of the air pressure sensor1. Check the vent pipe for obstructions
    2. Check and clean the air filter
    3. Replace Sensor    		Solution Details 027ENavien Air Pressure Sensor
    E028Water leak pipe line1. Check pipe line.
    2. Replace O ring    		Reset – Manual1. Navien O-Ring Kit
    2. Navien O-Ring P18
    3. Navien O-Ring P16
    E030Exhaust overheat: exhaust high limit switch shuts down the unit when the flue temperature exceeds 149 F or 65C1. 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 030E1. Inlet Water Filter
    2. Water Adjustment Valve NPE-A
    3. Water Adjustment Valve 30004834B
    4. Navien Flush Kit
    E032Cold water inlet: thermistor 2 -open1. Check thermistor
    2. Replace thermistor    		Solution Details 032ENavien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E033Cold water inlet: thermistor 2 -short1. Check thermistor
    2. Replace thermistor    		Solution Details 033ENavien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E034Abnormal – flow adjustment valve1. Check the flow adjustment valveNot DefinedWater Adjustment Valve
    1. Part 30004834B
    2. Part 30008245A
    E035Abnormal activity of the gas pressure sensor1. Check gas lineSolution Details 035EGas Pressure Flow Sensor
    E036Communication failure1. Contact Navien tech supportNot DefinedNone Needed
    E037Water leak inside unit1. Close cold water main
    2. Replace leaking part/O-Ring    		Solution Details 037E1. Navien O-Ring Kit
    2. Navien O-Ring P18
    3. Navien O-Ring P16
    E038Abnormal circulation pump1. Check the circulation pump.
    2. Check the water flow sensor
    3. Check the cold water main    		Not DefinedNavien Circulation Pumps.
    1. 30012768A
    2. 30000466A
    3. 30010780B
    4. 30000456B
    E039Abnormal – water flow sensor1. Check the water flow sensor 2. Replace water flow sensorNot DefinedNavien flow sensor
    E041Hot water outlet: thermistor 2 -open1. Check thermistor
    2. Replace thermistor    		Not DefinedNavien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E042Hot water outlet: thermistor 2 -short1. Check thermistor
    2. Replace thermistor    		Not DefinedNavien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E043Abnormal cascade connection1. Check model type 2. Check communication cableNot DefinedMulti-Unit Communication Cable
    E044Abnormal thermistor connection1. Check thermistor connection 2.Replace thermistorNot DefinedNavien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E045Abnormal – mixing valve1. Check the mixing valve 2.Replace Mixing Valve 3.Check mixing valve transformerNot Defined1. Mixing Valve Transformer
    2. Mixing Valve
    E046Abnormality in limit controlNot DefinedCall technical support (800-519-8794)High Limit Switch
    E047Abnormality in exhaust thermostatNot DefinedCall technical support (800-519-8794)Not Applicable
    E048Abnormal LPG gas pressure1. Check the LPG gas
    2. Fill the LPG gas 3. Check gas pressure flow sensor    		Not DefinedGas Pressure Flow Sensor
    E060Abnormality in dual venturi1. Reboot System 2. Replace dual venturiCall 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 Defined1. 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 DefinedCall 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 DefinedCall technical support <ahref=”tel:8005198794″>(800-519-8794)</ahref=”tel:8005198794″>Navien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E432Cold water inlet2: thermistor open or short circuitNot DefinedCall 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 <ahref=”tel:8005198794″>(800-519-8794)</ahref=”tel:8005198794″>Water Adjustment Valve
    1. Part# 30004834B
    2. Part# 30008245A
    E438Abnormal operation: circulation pumpNot Defined1. 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 DefinedCall technical support (800-519-8794)Gas Pressure Flow Sensor
    E441Hot water inlet2: thermistor open or short circuitNot DefinedCall technical support (800-519-8794)Navien Thermistor
    1. Blue wire Thermistor
    2. Red wire Thermistor
    3. Black wire Thermistor
    E445Abnormal operation: Bypass mixing valveNot DefinedCall technical support (800-519-8794)1. Mixing Valve Transformer
    2. Mixing Valve
    E515Abnormal operation: PCBTry new outletEnsure that the electrical cord is properly grounded.1. Part# 30008300A
    2. Part# 30012262A
    E517Abnormal operation: DIP switch settingNot DefinedCall technical support (800-519-8794)Not Applicable
    E593Abnormal operation: front panel keyNot DefinedCall technical support (800-519-8794)Front Panel Kdc-350P
    E615Abnormal operation: input and memoryNot DefinedCall technical support (800-519-8794)Not Applicable
    E736Abnormal operation: cascade communicationNot DefinedCall technical support (800-519-8794)Multi-Unit Communication Cable
    E760Flushing/service alarmNot DefinedCall for flush service (647-925-1930), your installer, or purchase flush kit below.Navien Flush Kit
    E782Abnormal operation: main panel communicationNot DefinedCall technical support (800-519-8794)Not Applicable

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