Navien Error Code E218: Bypass Servo Motor Failure

Severity
Warning
Type
digital display
Where to look
front panel
Estimated repair cost: $100 — $350 (parts + labor)
Warning: Your Navien boiler has detected a failure in the bypass servo motor, which may impact system performance. Schedule a professional repair soon.

How to Fix Navien Code E218

  1. Step 1: Turn off the boiler at the main power switch to ensure safety.
  2. Step 2: Check if the bypass valve is stuck or obstructed. If it's easy to turn, try gently moving it back and forth. If it's stuck, do not force it and call a professional.
  3. Step 3: If the issue persists, call a licensed HVAC technician to diagnose and repair the problem.

How to Reset Navien Code E218

  1. Turn off the unit using the power button on the front panel.
  2. Turn off the gas supply valve.
  3. Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
  4. Restore power at the breaker, then open the gas valve.
  5. Turn the unit back on. If the error returns, the underlying issue needs repair.

What does E218 mean?

The E218 error on your Navien boiler indicates a failure in the bypass servo motor. This motor is responsible for controlling the flow of water through the boiler's heat exchanger. When it fails, the boiler may not be able to maintain the correct water temperature, leading to inefficient heating. The error code will display on your boiler's digital display, and the unit will enter lockout mode to prevent further operation until the issue is resolved.

Affected Models

Source Documentation

ManualPageReasonAction
NFB-H Installation & Operation Manual 116 Heating Return Temp.Sensor Check thermistor connector.
Navien NCB-H Installation & Operation Manual 129 Heating Return Temp.Sensor Contact technical support at 1-800-519-8794.
Navien NFB-H Installation & Operation Manual 116 Heating Return Temp.Sensor Check thermistor connector.
Navien NFC-H Installation & Operation Manual 127 Abnormal operation: heating return thermistor Auto RESET
Navien NHB-H Installation & Operation Manual 119 Heating Return Temp.Sensor Check thermistor connector.
Navien NPF Installation & Operation Manual 126 Abnormal return water-temp sensor operation for lower limit

Replacement Parts

PartOEM NumberEst. Cost
Bypass Servo Motor NAVIEN 30001400
Control Board NAVIEN 30001200

Related Codes on Same Models

CodeDescriptionSeverity
E001 Ignition Failure Warning
E003 Abnormal Ignition Warning
E004 False Flame Detection Warning
E012 Flame Loss Warning
E016 Overheating Warning
E030 Exhaust Overheat Sensor Warning
E031 Inlet Thermistor Open/Short Warning
E046 Outlet Thermistor Open/Short Warning
E047 DHW Thermistor Open/Short Warning
E060 Fan Motor Abnormality Warning