Navien Tankless E013 Error Code — What It Means
E013 on a Navien tankless water heater indicates abnormal pump operation. The circulation pump is not running correctly, either because of a wiring fault, a failed pump motor, or a condition blocking normal operation. A secondary source lists code 013 as a thermistor problem, but Navien-specific troubleshooting identifies E013 as a pump fault. Confirm your exact model and displayed error before ordering parts, because generic code lists sometimes conflict with manufacturer diagnostics.
Common Causes
- Pump motor failure The circulation pump motor has burned out or seized and cannot spin when commanded.
- Loose or corroded pump wiring Connectors at the pump have come loose, corroded, or suffered intermittent contact that prevents the pump from receiving power.
- Blockage or mechanical restriction Scale, debris, or a closed valve in the hydronic path stalls the pump or prevents it from circulating water normally.
- Pump control board signal issue The main PCB is not sending the correct run signal to the pump, or the pump feedback circuit is faulty.
Step-by-Step Fix
- {‘lead’: ‘Confirm the displayed code on your exact Navien model’, ‘text’: ‘before proceeding, since generic lists sometimes label 013 as a thermistor fault rather than a pump fault.’}
- {‘lead’: ‘Turn off power to the water heater’, ‘text’: ‘at the breaker and close the incoming gas valve to make the unit safe for inspection.’}
- {‘lead’: ‘Inspect the pump wiring harness and connectors’, ‘text’: ‘for looseness, corrosion, or damage, and reseat or clean every connection at the circulation pump.’}
- {‘lead’: ‘Restore power and listen to the pump’, ‘text’: ‘when you open a hot tap; if the pump does not hum or vibrate, the motor is likely dead.’}
- {‘lead’: ‘Check for flow restrictions’, ‘text’: ‘by confirming that both the inlet filter and outlet valves are fully open and free of scale or debris.’}
- {‘lead’: ‘Replace the circulation pump assembly’, ‘text’: ‘if the motor is silent or runs rough, and retest the system after installation.’}
- {‘lead’: ‘If your model documentation lists 013 as thermistor-related’, ‘text’: ‘test the thermistor resistance and wiring per the service manual, and replace the sensor if out of spec.’}
Parts Often Needed
| Part | Notes |
|---|---|
| Navien circulation pump assembly | Amazon | Verify the pump part number for your exact Navien model before ordering. |
| Pump wiring harness or connector kit | Amazon | If the original harness is melted, cracked, or corroded at the pump terminals. |
When to Call a Pro
Call a licensed plumber or Navien service technician if you are not comfortable working with 120 V wiring, if the error persists after replacing the pump and checking all connections, or if your unit displays a different set of fault codes alongside E013. A technician has the factory diagnostic software to read live pump feedback, verify control-board output, and rule out intermittent faults that a visual inspection will miss. Professional service is also the safest choice if your unit is still under warranty, since DIY pump replacement can void coverage on some Navien models.