Noritz Error Code 51: Fan Motor Failure

How to Fix Noritz Code 51

1. Check if the power switch is turned on and the circuit breaker is in the ON position
2. Listen for any unusual noises coming from the unit, which could indicate a different issue
3. Contact a licensed HVAC technician for a professional diagnosis and repair

How to Reset Noritz Code 51

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.

Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.

What Does Noritz Error Code 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.

Common Causes

• Fan motor failure due to wear and tear over time
• Electronic control circuit failure, causing the motor to stop receiving power
• Blockage in the venting system, causing the motor to overheat and fail
• Incorrect installation or improper venting, leading to excessive motor strain

Diagnostic Steps

Replacement Parts

Related Codes on Same Models

Other codes that affect the same Noritz model families as 51.