How to Fix Noritz Error Codes

It’s no surprise that tankless water heaters, including Noritz models, can run into error codes during their lifespan. While some error codes indicate severe issues, others, like error codes 51 and 90, signal specific maintenance or repair needs. Knowing how to address these error codes is key to keeping your water heater in top shape.

At Monkey Wrench Plumbing, Heating, Air & Electric, we’ve spent nearly two decades diagnosing and fixing tankless water heater issues in the greater Los Angeles area. Our close relationship with Noritz gives us expert insights into addressing even the trickiest error codes. Let’s dive into two of the most common Noritz error codes—51 and 90—what they mean, and how to resolve them.

What Does Noritz Error Code 51 Mean?

Error code 51 points to gas manifold issues, such as failure or water dripping onto the manifold. This issue can lead to gas pressure problems, which can be dangerous if left unresolved. Diagnosing the exact cause requires a professional inspection.

The best course of action is to call a technician to safely navigate the combustion components of your unit and determine whether the issue stems from gas pressure or water damage to the manifold.

What Does Noritz Error Code 90 Mean?

Error code 90 is a maintenance code that arises from scale buildup in your unit’s heat exchanger. This is often caused by improper or infrequent maintenance, especially in areas with hard water like Los Angeles County.

Scale buildup forces the heat exchanger to work harder to reach the set temperature, which can lead to early breakdowns or even damage that requires replacement.

How Do You Fix Noritz Error Codes 51 and 90?

For Error Code 51:
Your technician will inspect the gas manifold and check for water damage or gas pressure issues. If water has damaged the manifold, it will need to be replaced. If it’s a gas pressure issue, they can adjust the settings using the circuit board or keypad based on Noritz’s specifications for your model.

For Error Code 90:
Because this is a maintenance code, your technician will perform a descaling process and routine maintenance to clear out the buildup in your heat exchanger. They’ll also recommend scheduling annual maintenance to prevent this issue from recurring and extend the lifespan of your water heater

Experiencing Another Issue?

Noritz tankless water heaters are built to last but, like any appliance, may occasionally encounter error codes. For instance, error code 12 signals gas pressure or airflow issues, which can be caused by debris blocking the exhaust or intake.

Regardless of the error code, calling a technician is always the safest approach. Some issues require working with combustion elements, making DIY fixes potentially dangerous.

Ready to Resolve Noritz Error Codes?

We’ve covered two common Noritz error codes—51 and 90—and how to fix them. With this knowledge, you can confidently take the next steps to get your tankless water heater running smoothly again.

At Monkey Wrench Plumbing, Heating, Air & Electric, we specialize in resolving tankless water heater issues. Our partnership with Noritz means we have the expertise and resources to fix your unit correctly the first time.

If you’re facing any error code or want to prevent future ones, call us at (818) 213-1773 or visit our tankless water heater service page to schedule a consultation. To ensure your system operates at its best, check out our guides on tankless water heater maintenance and our ultimate guide to tankless water heaters.