Navien Error Codes

    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.

    New — Replacement Parts Available Here!

    Please cross reference ALL replacement parts with your Navien model.

    Error Code – E001

    FAULT = Water 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.

    Error Code Solutions

    Solution Details 001E OR power Supply

    Replacement Parts

    Error Code – E002

    FAULT = Low Water Pressure

    1. Wait until water supplement is terminated.

    Error Code Solutions

    Reset Is Automatic

    Replacement Parts

    • Not Applicable

    Error Code – E003

    FAULT = 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

    Error Code Solutions

    Scenario 1
    Scenario 2
    Scenario 3

    Replacement Parts

    Error Code – E004

    FAULT = False flame detection

    1. Ensure ground wire is connected
    2. Check the igniter for spark

    Error Code Solutions

    Solution Details 004E

    Replacement Parts

    Error Code – E007

    FAULT = Hot water outlet: thermistor -open

    1. Check the thermistor
    2. Replace the thermistor

    Error Code Solutions

    Solution Details 007E

    Replacement Parts

    Error Code – E008

    FAULT = Hot water outlet: thermistor -short

    1. Check the thermistor
    2. Replace the thermistor

    Error Code Solutions

    Solution Details 008E

    Replacement Parts

    Error Code – E009

    FAULT = Abnormal fan motor activity

    1. Check and clean the air filter
    2. Check and clean the fan motor
    3. If faulty, replace fan.

    Error Code Solutions

    Solution Details 009E

    Replacement Parts

    Error Code – E010

    FAULT = Abnormal Air Pressure

    1. Check the vent pipe for obstructions
    2. Check and clean the air filter

    Error Code Solutions

    Solution Details 010E

    Replacement Parts

    • Not Applicable

    Error Code – E011

    FAULT = High Water Pressure

    1. Check the water pressure sensor.
    2. Check water pressure wire and sensor connection
    3. Replace if needed

    Error Code Solutions

    Automatic Reset or replace sensor.

    Replacement Parts

    Error Code – E012

    FAULT = Flame loss

    1. Check the main gas line (valve open?)
    2. Check intake air pipe
    3. Check the ground wire
    4. Check power supply

    Error Code Solutions

    Solution Details 012E

    Replacement Parts

    Error Code – E015

    FAULT = Abnormal control board

    1. Check power supply
    2. Check the GFI
    3. Replace Control Board

    Error Code Solutions

    Not Defined

    Replacement Parts

    Error Code – E016

    FAULT = 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
    5. Replace water strainer, flow adjustment valve, or heat exchanger if necessary.

    Error Code Solutions

    Solution Details 016E

    Replacement Parts

    Error Code – E021

    FAULT = Cold water inlet: Thermistor 1 -open

    1. Check thermistor,
    2. Check thermistor connection and wire
    3. Replace thermistor if needed

    Error Code Solutions

    Solution Details 021E

    Replacement Parts

    Error Code – E022

    FAULT = Cold water inlet: Thermistor 1 -short

    1. Check thermistor,
    2. Check thermistor connection and wire
    3. Replace thermistor if needed

    Error Code Solutions

    Solution Details 022E

    Replacement Parts

    Error Code – E027

    FAULT = Abnormal activity of the air pressure sensor

    1. Check the vent pipe for obstructions
    2. Check and clean the air filter
    3. Replace Sensor

    Error Code Solutions

    Solution Details 027E

    Replacement Parts

    Error Code – E028

    FAULT = Water leak pipe line

    1. Check pipe line.
    2. Replace O ring

    Error Code Solutions

    Reset – Manual

    Replacement Parts

    Error Code – E030

    FAULT = Exhaust overheat

    1. Exhaust high limit switch shuts down the unit when the flue temperature exceeds 149 F or 65C
    2. Turn off the unit for at least 30 minutes then restart.
    3. Clean the inlet water strainer
    4. Check the automatic flow adjustment valve
    5. Check the heat exchanger: remove and clean with a cleaning solution

    Error Code Solutions

    Solution Details 030E

    Replacement Parts

    Error Code – E032

    FAULT = Cold water inlet: Thermistor 2 -open

    1. Check thermistor
    2. Replace thermistor

    Error Code Solutions

    Solution Details 032E

    Replacement Parts

    Error Code – E033

    FAULT = Cold water inlet: Thermistor 2 -short

    1. Check thermistor
    2. Replace thermistor

    Error Code Solutions

    Solution Details 033E

    Replacement Parts

    Error Code – E034

    FAULT = Abnormal – flow adjustment valve

    1. Check the flow adjustment valve

    Error Code Solutions

    Not Defined

    Replacement Parts

    Error Code – E035

    FAULT = Abnormal activity of the gas pressure sensor

    1. Check gas line

    Error Code Solutions

    Solution Details 035E

    Replacement Parts

    Error Code – E036

    FAULT = Communication failure

    1. Contact Navien tech support

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    • Not Applicable

    Error Code – E037

    FAULT = Water leak inside unit

    1. Close cold water main
    2. Replace leaking part/O-Ring
    3. Check inside front cover/panel for possible emergency repair kit (some models contain one).

    Error Code Solutions

    Solution Details 037E

    Replacement Parts

    Error Code – E038

    FAULT = Abnormal circulation pump

    1. Check the circulation pump.
    2. Check the water flow sensor
    3. Check the cold water main
    4. Check wires and connections for circulation pump and flow sensor.
    5. Replace parts if needed

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E039

    FAULT = Abnormal – water flow sensor

    1. Check the water flow sensor
    2. Confirm flow sensor connection
    3. Replace water flow sensor

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E041

    FAULT = Hot water outlet: Thermistor 2 -open

    1. Check thermistor
    2. Confirm thermistor connection
    3. Replace thermistor

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E042

    FAULT = Hot water outlet: Thermistor 2 -short

    1. Check thermistor
    2. Confirm thermistor connection
    3. Replace thermistor

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support t

    Replacement Parts

    Error Code – E043

    FAULT = Abnormal cascade connection

    1. Check model type
    2. Check communication cable

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E044

    FAULT = Abnormal thermistor connection

    1. Check thermistor
    2. Confirm thermistor connection
    3. Replace thermistor

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E045

    FAULT = Abnormal – mixing valve

    1. Check the mixing valve
    2. Replace mixing valve
    3. Check mixing valve transformer
    4. Replace mixing valve transformer

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E046

    FAULT = Abnormality in limit control

    1. Not Defined

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E047

    FAULT = Abnormality in exhaust thermostat

    1. Not Defined

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    • Not Applicable

    Error Code – E048

    FAULT = Abnormal LPG gas pressure

    1. Check the LPG gas and pressure reducing valve
    2. Fill the LPG gas if needed
    3. Check gas pressure flow sensor
    4. Replace gas pressure flow sensor

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E060

    FAULT = Abnormality in dual venturi

    1. Reboot System (unplug system for 2-3 minutes and plug back in)
    2. Replace dual venturi

    Error Code Solutions

    Call technic Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E109

    FAULT = Abnormal operation: fan motor

    1. Clean the intake air filter.
    2. Reboot system (unplug system for 2-3 minutes and plug back in)
    3. Replace Fan Motor

    Error Code Solutions

    Not Defined

    Replacement Parts

    Error Code – E110

    FAULT =

    1. Ensure that the exhaust pipe is free of obstructions.
    2. Clean the intake air filter.
    3. Check or replace air pressure sensor

    Error Code Solutions

    Not Defined

    Replacement Parts

    Error Code – E407

    FAULT = Hot water outlet: Thermistor open or short circuit

    1. Check thermistor
    2. Confirm thermistor connection
    3. Replace thermistor

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E421

    FAULT = Cold water inlet 1: Thermistor open or short circuit

    1. Check thermistor
    2. Confirm thermistor connection
    3. Replace thermistor

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E432

    FAULT = Cold water inlet 2: Thermistor open or short circuit

    1. Check thermistor
    2. Confirm thermistor connection
    3. Replace thermistor if needed

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E434

    FAULT = Abnormal Operation: water adjustment valve

    1. Check adjustment valve.
    2. Check adjustment valve connection
    3. Replace valve if needed

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E438

    FAULT = Abnormal Operation: circulation pump

    1. External: Ensure that all water supply and return lines are open.
    2. Internal: Check the direction of the 2-way valve.

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E439

    FAULT = Abnormal Operation: flow sensor

    1. Confirm water supply and flow
    2. Check flow sensor
    3. Check flow sensor wire and connection to control board
    4. Remove flow sensor and clean or descale turbine
    5. Replace flow sensor if needed

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E441

    FAULT = Hot water inlet 2: Thermistor open or short circuit

    1. Check thermistor
    2. Confirm thermistor connection
    3. Replace thermistor if needed

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E445

    FAULT = Abnormal Operation: Bypass mixing valve

    1. Faulty mixing valve sensor
    2. Check wiring and connection to main board
    3. Confirm valve isn’t blocked or damaged
    4. Replace valve
    5. Replace pcb main board

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E480

    FAULT = External Tank Thermistor Open or Short (System Boiler Thermistor)

    1. Check thermistor connection and wire
    2. Confirm connection is not wet causing a short
    3. Replace thermistor if needed

    Error Code Solutions

    Issue with external tank thermistor being shorted, open, or temperature below 14°F (-10°C)

    Replacement Parts

    Error Code – E515

    FAULT = Abnormal operation: PCB

    1. Try new outlet
    2. Ensure electrical cord is properly grounded
    3. Visually inspect pcb
    4. Inspect igniter and connection
    5. inspect fan and connection
    6. Inspect dual venturi and connection
    7. Inspect 3 way valve and connection
    8. Replace PCB if necessary

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E517

    FAULT = Abnormal operation: DIP switch setting

    1. Dip switch setting error
    2. Confirm all dip switches are set correctly
    3. Check front panel dip switches as well as PCB dip switches

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E593

    FAULT = Abnormal Operation: front panel key

    1. Front panel display or key issue
    2. Reboot system by unplugging, waiting 2-3 minutes and plug in again
    3. If error persists replace front panel

    Error Code Solutions

    Follow Above Steps

    Replacement Parts

    Error Code – E594

    FAULT = Communication or partial communication error (EEPROM error)

    1. Inspect PCB board
    2. Check wiring and connections to PCB from major components
    3. Focus on connections from flame rod, exhaust sensor, as well as pressure sensor.
    4. PCB board may need to be replaced

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E615

    FAULT = Abnormal Operation: input and memory

    1. Reboot system, unplug, wait 2-3 minutes and plug in again
    2. Inspect and confirm secure wiring and connection on PCB
    3. Test the pressure sensor output voltage for abnormalities
    4. Replace PCB or pressure sensor as required

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E736

    FAULT = Abnormal Operation: cascade communication

    1. Check PCB model is compatible with cascade communication cable
    2. Ensure cascade cable is securly connected to PCB
    3. Confirm cascade setting are setup correctly
    4. Reboot system, unplug, wait 2-3 minutes and plug in again
    5. If error remains try tecnical support or cascade cable replacement

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E740

    FAULT = Abnormal Operation: Outdoor Sensor Error

    1. Error with outdoor temperature sensor
    2. Confirm connection is secure on PCB
    3. Inspect and ensure wire from system to outdoor sensor hasn’t been damaged or cut.
    4. Drying outdoor sensor for 24h indoors can occasional temporairly rectify the issue.
    5. Replace outdoor sensor

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E760

    FAULT = Flushing/Service alarm

    1. System needs to be serviced/flushed
    2. Removal of scale and lime buildup increases lifespan and maintains high efficiency
    3. Tankless flush instructions

    Error Code Solutions

    Not Applicable

    Replacement Parts

    Error Code – E782

    FAULT = Abnormal Operation: main panel communication

    1. Inspect PCB for loose connection or signs of water
    2. Call technical support for addional help
    3. PCB replacement may be necessary

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E783

    FAULT = Abnormal Operation: OT remote controller error

    1. Assess remote controller(s)
    2. Ensure wiring is still in good condition
    3. Reboot system, unplug, wait 2-3 minutes and plug in again
    4. If error persists contact technical support

    Error Code Solutions

    Call Navien technical support (800-519-8794) for additional support

    Replacement Parts

    Error Code – E787

    FAULT = Abnormal Operation: Flow Switch

    1. External flow switch causing error
    2. Confirm supply water line is charged and supplying water
    3. Confirm flow switch position as on or off position
    4. Replace flow switch if necessary

    Error Code Solutions

    power Supply

    Replacement Parts

    New — Replacement Parts Available Here!