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Back to Navien NAE Series

Navien NAE Series troubleshooting and error codes

Use this table to identify what the visible code may mean and what information to share when scheduling service. Keep checks simple and visible; do not open electrical, refrigerant, gas, or sealed equipment compartments.

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Error-code table

Search codes for NAE Series

Code Meaning System area Safe first step Action
E201 Indoor return air sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E202 Indoor coil temperature sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E203 Indoor leaving air temperature sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E204 Outdoor ambient sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E205 Outdoor coil temperature sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E206 Compressor discharge temperature sensor error Temperature / sensor Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E207 Suction temperature sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E208 Pressure sensor error Temperature / sensor Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E209 Hydro module water temperature sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E210 Hydro module flow or water temperature sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E501 Indoor/outdoor communication error Controls / communication Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E505 Hydro module communication error Controls / communication Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E506 Outdoor control communication error Controls / communication Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E507 Controller communication error Controls / communication Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E561 Outdoor EEPROM or setting error Controls / communication Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E562 Indoor EEPROM or setting error Controls / communication Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E702 System setup or communication error Controls / communication Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E801 Communication error Controls / communication Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E802 Compressor current sensor error Temperature / sensor Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E803 DC link sensor error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E804 PFCM current A error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E805 PFCM current B error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E806 Input voltage sensor error Temperature / sensor Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E807 Software compressor over-current error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E808 Compressor over-current protection Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E809 Compressor current limit error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E810 Hardware compressor over-current error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E811 PFC over-current error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E812 Estimator fault error Equipment control Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E813 Compressor starting error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E814 Wire missing error Equipment control Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E815 Heatsink over-temperature cumulative error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E816 DC under-voltage error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E817 DC over-voltage error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E818 AC under-voltage error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E819 AC over-voltage error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E820 PFC unbalanced current error Refrigerant / inverter Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E821 Fan motor cumulative error Airflow / fan Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E822 Discharge FET error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details
E823 Stator overheat cumulative error Equipment control Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service. View details
E824 PBA over-temperature error Temperature / sensor Record the Navien code, check visible intake, exhaust, filter, thermostat, controller, and clearance conditions without opening panels, and schedule service if the condition remains. View details

Safety note

What is safe to check before service

These pages are meant to help document the issue, not replace diagnosis. GreenFlow should handle pressure-switch, electrical, refrigerant, lockout, recurring, and warranty-related conditions.

Safe visible checks

  • Thermostat display and settings
  • Filter condition and return-air path
  • Visible outdoor-unit obstruction
  • Photos of the code, unit, and nameplate

Stop and call

  • Repeated lockouts or recurring faults
  • Pressure-switch or sensor faults
  • Electrical odor, unusual noise, or ice buildup
  • Any sealed cabinet, refrigerant, gas, or warranty issue

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