Navien Error Code E003
Ignition Failure
Check this first
- Check if the manual gas valve is open
- Check the main gas supply
Leave to a technician
- Verify that gas pressure is within operating range
- Check Dual Venturi for proper operation
- Check DIP Switch settings
- Check if the igniter is sparking
- Tighten the ground terminals on the heat exchanger
Navien Error Code E004
False flame detection
Leave to a technician
- Check if the igniter is sparking
- Tighten the ground terminals on the heat exchanger
Navien Error Code E012
Flame Loss
Check this first
- Check if the main gas valve is open
- Check the intake air filter
- Check the power supply
Leave to a technician
- Verify the incoming gas pressure
- Check the ground wire
- Tighten the ground terminals on the heat exchanger
- Adjust the anti-short cycle time
Navien Error Code E016
Heat exchanger overheat
Check this first
- Turn OFF the unit, wait at least 30 min, and then restart
- Clean the inlet water filter and strainer
- Check the heat exchanger and flush it if required
Leave to a technician
- Check the high limit switch and PCB
- Check pump operation (for A models only)
- Check the 3-way valve
- Check DIP Switch settings
Navien Error Code E030
Exhaust Overheat: exhaust limit sensor shuts down the unit when the flue temperature exceeds 230 °F for more than 10 seconds.
Check this first
- Turn OFF the unit, wait at least 30 min, and then restart
- Clean the inlet water filter and strainer
- Check the heat exchanger and flush it if required
Leave to a technician
- Check exhaust thermistor and verify [K] value in DIAGNOSTIC mode
- Check DIP Switch settings
- Check the water adjustment valve
Navien Error Code E047
Abnormal exhaust thermistor open or short
Leave to a technician
- Check exhaust thermistor connection
- Check for proper connection to the PCB
Navien Error Code E060
Abnormal Dual Venturi Limit Switch operation
Leave to a technician
- Check the Dual Venturi connection
- Test Dual Venturi for proper operation using TEST mode
- Check gas orifice for obstructions
Navien Error Code E109
Abnormal fan motor activity
Check this first
- Check and clean the intake air filter
Leave to a technician
- Verify proper voltage and wire connection
- Check and clean the fan motor
Navien Error Code E110
Exhaust blockage
Check this first
- Check the intake/exhaust/condensate drain pipe for obstructions.(ice, snow, wildlife, etc)
- Check and clean the intake air filter
Leave to a technician
- As a temporarily solution for troubleshooting purposes,restart the unit and/or remove the front cover
- Check if the igniter is sparking
- Tighten the ground terminals on the heat exchanger
Navien Error Code E407
Abnormal Hot water outlet thermistor open or short
Leave to a technician
- Check the thermistor
- Replace the thermistor
Navien Error Code E421
Abnormal Cold water inlet thermistor open or short
Check this first
- It's time to a or contact Warm Welcome
- Check the thermistor
- Verify [C] value in DIAGNOSTIC mode
- Replace the thermistor
Navien Error Code E432
Abnormal Cold water inlet2: thermistor open or short
Leave to a technician
- Check the thermistor
- Check thermistor voltage and resistance values
- Replace the thermistor
Navien Error Code E434
Abnormal water adjustment valve open or short
Leave to a technician
- Check the water adjustment valve
Navien Error Code E438
Abnormal circulation pump ("A" models only)
Check this first
- Check the circulation pump
- Check water filter for blockage
- Check the cold water main line
Leave to a technician
- Check the flow sensor
- Set to Internal Recirculation mode and verify flow rate
Navien Error Code E439
Abnormal flow sensor
Leave to a technician
- Check the flow sensor
Navien Error Code E441
Abnormal Hot water inlet2: thermistor open or short
Leave to a technician
- Check the thermistor
- Replace the thermistor
Navien Error Code E445
Abnormal mixing valve open or short
Leave to a technician
- Check the mixing valve
Navien Error Code E515
Abnormal PCB communication
Leave to a technician
- Subcode 1~7 PCB > Ignitor: Check the PCB
- Subcode 8 PCB > Ignitor: Check PCB connection and ignitor
- Subcode 9 PCB > Fan: Check PCB connection and fan
- Subcode 10 Abnormal monitoring device of PCB: Check PCB connection and dual venturi
- Subcode 10~12 Abnormal communication between PCB and Dual Venturi: Check PCB connection and dual venturi
Navien Error Code E517
Abnormal dip switch setting
Leave to a technician
- Check the dip switches on the front panel and PCB
Navien Error Code E593
Abnormal panel key
Leave to a technician
- Check the Panel
Navien Error Code E594
Abnormal input data
Leave to a technician
- Subcode 0 High limit switch of Heat exchanger: Check PCB
- Subcode 1 Exhaust sensor: check exhaust sensor connection and sensor
- Subcode 2 Flame rod: check flame rod connection and flame sensor
- Subcode 3~14 PCB: check the PCB
- Subcode 15 Below the range of input data from Pressure sensor: check pressure sensor wiring and output voltage of pressure sensor
- Subcode 16 Over the range of input data from Pressure sensor: check pressure sensor wiring and output voltage of pressure sensor
Navien Error Code E736
Abnormal cascade communication
Check this first
- Check the Ready-link cable
Leave to a technician
- Check the cascade settings
- Check the PCB version for compatibility
Navien Error Code E740
Abnormal outdoor temperature sensor open or short (appears only when the outdoor reset curve is enabled)
Leave to a technician
- Ensure that the outdoor reset curve is configured properly
- Check the outdoor temperature sensor wiring connection
Navien Error Code E760
Flushing / Service alarm
Check this first
- A heat exchanger flush is required
Navien Error Code E782
Abnormal main panel communication
Check this first
- Check the PCB
Navien Error Code E785
Abnormal flow sensor operation
Check this first
- Check the Cold Water line
- Check the Flow Switch connection
Codes and checks are for general guidance. Gas, venting, and electrical work on a water heater should be done by a licensed plumber.