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
- Clean the inlet water strainer.
- Check the automatic flow sensor.
- Check the heat exchanger, remove and clean with a solution
- Check PCB board, replace if faulty.
Error Code Solutions
Solution Details 001E OR power Supply
Replacement Parts
- Inlet Water Filter
- Water Adjustment Valve NPE-A
- Water Adjustment Valve 30004834B
- Navien Flush Kit
- Navien CB 30000181A
- Navien CB 30012262A
- Navien CB 30008300A
Error Code – E002
FAULT = Low Water Pressure
- Wait until water supplement is terminated.
Error Code Solutions
Reset Is Automatic
Replacement Parts
- Not Applicable
Error Code – E003
FAULT = Ignition Failure
- Check to see if the main gas supply is on
- Check that the power is on
- Check the igniter for spark
Error Code Solutions
Scenario 1
Scenario 2
Scenario 3
Replacement Parts
Error Code – E004
FAULT = False flame detection
- Ensure ground wire is connected
- Check the igniter for spark
Error Code Solutions
Replacement Parts
Error Code – E007
FAULT = Hot water outlet: thermistor -open
- Check the thermistor
- Replace the thermistor
Error Code Solutions
Replacement Parts
- Navien Thermistors
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E008
FAULT = Hot water outlet: thermistor -short
- Check the thermistor
- Replace the thermistor
Error Code Solutions
Replacement Parts
- Navien Thermistors
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E009
FAULT = Abnormal fan motor activity
- Check and clean the air filter
- Check and clean the fan motor
- If faulty, replace fan.
Error Code Solutions
Replacement Parts
Error Code – E010
FAULT = Abnormal Air Pressure
- Check the vent pipe for obstructions
- Check and clean the air filter
Error Code Solutions
Replacement Parts
- Not Applicable
Error Code – E011
FAULT = High Water Pressure
- Check the water pressure sensor.
- Check water pressure wire and sensor connection
- Replace if needed
Error Code Solutions
Automatic Reset or replace sensor.
Replacement Parts
Error Code – E012
FAULT = Flame loss
- Check the main gas line (valve open?)
- Check intake air pipe
- Check the ground wire
- Check power supply
Error Code Solutions
Replacement Parts
Error Code – E015
FAULT = Abnormal control board
- Check power supply
- Check the GFI
- Replace Control Board
Error Code Solutions
Not Defined
Replacement Parts
Error Code – E016
FAULT = Overheating of heat exchanger
- Turn off the system for at least 30 minutes then restart.
- Clean the inlet water strainer
- Check the automatic flow adjustment valve
- Check the heat exchanger: remove and clean with a cleaning solution
- Replace water strainer, flow adjustment valve, or heat exchanger if necessary.
Error Code Solutions
Replacement Parts
Error Code – E021
FAULT = Cold water inlet: Thermistor 1 -open
- Check thermistor,
- Check thermistor connection and wire
- Replace thermistor if needed
Error Code Solutions
Replacement Parts
- Navien Replacement Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E022
FAULT = Cold water inlet: Thermistor 1 -short
- Check thermistor,
- Check thermistor connection and wire
- Replace thermistor if needed
Error Code Solutions
Replacement Parts
- Navien Replacement Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E027
FAULT = Abnormal activity of the air pressure sensor
- Check the vent pipe for obstructions
- Check and clean the air filter
- Replace Sensor
Error Code Solutions
Replacement Parts
Error Code – E028
FAULT = Water leak pipe line
- Check pipe line.
- Replace O ring
Error Code Solutions
Reset – Manual
Replacement Parts
Error Code – E030
FAULT = Exhaust overheat
- Exhaust high limit switch shuts down the unit when the flue temperature exceeds 149 F or 65C
- Turn off the unit for at least 30 minutes then restart.
- Clean the inlet water strainer
- Check the automatic flow adjustment valve
- Check the heat exchanger: remove and clean with a cleaning solution
Error Code Solutions
Replacement Parts
Error Code – E032
FAULT = Cold water inlet: Thermistor 2 -open
- Check thermistor
- Replace thermistor
Error Code Solutions
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E033
FAULT = Cold water inlet: Thermistor 2 -short
- Check thermistor
- Replace thermistor
Error Code Solutions
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E034
FAULT = Abnormal – flow adjustment valve
- Check the flow adjustment valve
Error Code Solutions
Not Defined
Replacement Parts
- Water Adjustment Valve
- Part 30004834B
- Part 30008245A
Error Code – E035
FAULT = Abnormal activity of the gas pressure sensor
- Check gas line
Error Code Solutions
Replacement Parts
Error Code – E036
FAULT = Communication failure
- 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
- Close cold water main
- Replace leaking part/O-Ring
- Check inside front cover/panel for possible emergency repair kit (some models contain one).
Error Code Solutions
Replacement Parts
Error Code – E038
FAULT = Abnormal circulation pump
- Check the circulation pump.
- Check the water flow sensor
- Check the cold water main
- Check wires and connections for circulation pump and flow sensor.
- 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
- Check the water flow sensor
- Confirm flow sensor connection
- 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
- Check thermistor
- Confirm thermistor connection
- Replace thermistor
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E042
FAULT = Hot water outlet: Thermistor 2 -short
- Check thermistor
- Confirm thermistor connection
- Replace thermistor
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support t
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E043
FAULT = Abnormal cascade connection
- Check model type
- 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
- Check thermistor
- Confirm thermistor connection
- Replace thermistor
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E045
FAULT = Abnormal – mixing valve
- Check the mixing valve
- Replace mixing valve
- Check mixing valve transformer
- 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
- Not Defined
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Potential part – High Limit Switch
Error Code – E047
FAULT = Abnormality in exhaust thermostat
- 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
- Check the LPG gas and pressure reducing valve
- Fill the LPG gas if needed
- Check gas pressure flow sensor
- 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
- Reboot System (unplug system for 2-3 minutes and plug back in)
- 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
- Clean the intake air filter.
- Reboot system (unplug system for 2-3 minutes and plug back in)
- Replace Fan Motor
Error Code Solutions
Not Defined
Replacement Parts
Error Code – E110
FAULT =
- Ensure that the exhaust pipe is free of obstructions.
- Clean the intake air filter.
- 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
- Check thermistor
- Confirm thermistor connection
- Replace thermistor
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E421
FAULT = Cold water inlet 1: Thermistor open or short circuit
- Check thermistor
- Confirm thermistor connection
- Replace thermistor
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E432
FAULT = Cold water inlet 2: Thermistor open or short circuit
- Check thermistor
- Confirm thermistor connection
- Replace thermistor if needed
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E434
FAULT = Abnormal Operation: water adjustment valve
- Check adjustment valve.
- Check adjustment valve connection
- Replace valve if needed
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Water Adjustment Valve
- Part# 30004834B
- Part# 30008245A
Error Code – E438
FAULT = Abnormal Operation: circulation pump
- External: Ensure that all water supply and return lines are open.
- Internal: Check the direction of the 2-way valve.
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Navien Circulation Pumps.
- Part# 30012768A
- Part# 30000466A
- Part# 30010780B
- Part# 30000456B
Error Code – E439
FAULT = Abnormal Operation: flow sensor
- Confirm water supply and flow
- Check flow sensor
- Check flow sensor wire and connection to control board
- Remove flow sensor and clean or descale turbine
- 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
- Check thermistor
- Confirm thermistor connection
- Replace thermistor if needed
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E445
FAULT = Abnormal Operation: Bypass mixing valve
- Faulty mixing valve sensor
- Check wiring and connection to main board
- Confirm valve isn’t blocked or damaged
- Replace valve
- 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)
- Check thermistor connection and wire
- Confirm connection is not wet causing a short
- Replace thermistor if needed
Error Code Solutions
Issue with external tank thermistor being shorted, open, or temperature below 14°F (-10°C)
Replacement Parts
- Navien Thermistor
- Blue wire Thermistor
- Red wire Thermistor
- Black wire Thermistor
Error Code – E515
FAULT = Abnormal operation: PCB
- Try new outlet
- Ensure electrical cord is properly grounded
- Visually inspect pcb
- Inspect igniter and connection
- inspect fan and connection
- Inspect dual venturi and connection
- Inspect 3 way valve and connection
- Replace PCB if necessary
Error Code Solutions
Call Navien technical support (800-519-8794) for additional support
Replacement Parts
- Navien PCB 30000181A
- Navien PCB 30012262A
- Navien PCB 30008300A
- Dual Venturi – 30012770A
- Dual Venturi – 30008909A
- Fan 30008834A
- Fan 30000405A
- Flame Rod NPE/NCB
- Flame Rod CR/CC/CH/NR/NP
- Flame Rod CR/CC/CH/NR/NP
- Flame Rod NPE/NCB
Error Code – E517
FAULT = Abnormal operation: DIP switch setting
- Dip switch setting error
- Confirm all dip switches are set correctly
- 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
- Front panel display or key issue
- Reboot system by unplugging, waiting 2-3 minutes and plug in again
- 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)
- Inspect PCB board
- Check wiring and connections to PCB from major components
- Focus on connections from flame rod, exhaust sensor, as well as pressure sensor.
- 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
- Reboot system, unplug, wait 2-3 minutes and plug in again
- Inspect and confirm secure wiring and connection on PCB
- Test the pressure sensor output voltage for abnormalities
- 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
- Check PCB model is compatible with cascade communication cable
- Ensure cascade cable is securly connected to PCB
- Confirm cascade setting are setup correctly
- Reboot system, unplug, wait 2-3 minutes and plug in again
- 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
- Error with outdoor temperature sensor
- Confirm connection is secure on PCB
- Inspect and ensure wire from system to outdoor sensor hasn’t been damaged or cut.
- Drying outdoor sensor for 24h indoors can occasional temporairly rectify the issue.
- 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
- System needs to be serviced/flushed
- Removal of scale and lime buildup increases lifespan and maintains high efficiency
- Tankless flush instructions
Error Code Solutions
Not Applicable
Replacement Parts
Error Code – E782
FAULT = Abnormal Operation: main panel communication
- Inspect PCB for loose connection or signs of water
- Call technical support for addional help
- 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
- Assess remote controller(s)
- Ensure wiring is still in good condition
- Reboot system, unplug, wait 2-3 minutes and plug in again
- 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
- External flow switch causing error
- Confirm supply water line is charged and supplying water
- Confirm flow switch position as on or off position
- Replace flow switch if necessary
Error Code Solutions
power Supply
Replacement Parts
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