Noritz Error Code 51: Fan Motor Failure
Warning: Your Noritz water heater's fan motor has failed, causing the system to shut down. This is not an immediate safety risk, but it does require professional repair.
How to Fix Noritz Code 51
- Check if the power switch is turned on and the circuit breaker is in the ON position
- Listen for any unusual noises coming from the unit, which could indicate a different issue
- Contact a licensed HVAC technician for a professional diagnosis and repair
How to Reset Noritz Code 51
- Turn off the unit using the power button on the front panel.
- Turn off the gas supply valve.
- Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
- Restore power at the breaker, then open the gas valve.
- Turn the unit back on. If the error returns, the underlying issue needs repair.
What does 51 mean?
The Noritz 51 error code indicates that the fan motor in your condensing tankless water heater has stopped working. This motor is responsible for drawing combustion air into the unit and exhausting the byproducts of combustion out. When it fails, the system automatically shuts down to prevent any potential safety hazards. This error is not typically caused by a simple power issue; it's usually due to a faulty motor or a problem with the motor's control circuit.
Affected Models
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Fan Motor Assembly | NOR-100000026 | — |
| Control Circuit Board | NOR-100000035 | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| 10 | Flame Failure | Warning |
| 11 | Ignition Failure | Warning |
| 14 | Thermal Fuse Failure | Warning |
| 29 | Condensate Drain Issue | Warning |
| 31 | Inlet Thermistor Failure | Warning |
| 32 | Outlet Thermistor Failure | Warning |
| 33 | Heat Exchanger Thermistor Failure | Warning |
| 43 | Water Level/Neutralizer Issue | Warning |
| 45 | Water Leak Detected | Warning |
| 61 | Fan Motor Failure | Warning |