Have you ever stepped into the shower only to be greeted by a sudden blast of cold water? If you own a Noritz tankless water heater, you might have encountered error code 51, leaving you frustrated and confused. This common issue can disrupt your daily routine, but understanding it doesn’t have to be a headache.

Table of Contents

Key Takeaways

Understanding Error Code 51: This error indicates issues with ignition or flame detection in Noritz tankless water heaters, potentially leading to unwanted cold showers.
Common Causes: Key reasons for error code 51 include malfunctioning flame sensors, blocked venting systems, and insufficient gas supply, all of which disrupt normal operation.
Troubleshooting Steps: Initial checks should include ensuring a secure power supply, examining gas supply and water flow, and resetting the unit, which can resolve minor issues.
Regular Maintenance: Routine tasks like descaling, inspecting filters, and checking venting systems are essential to prevent error codes and ensure optimal performance.
Importance of Professional Inspections: Scheduling annual professional inspections can help identify problems early, extending the lifespan of your water heater and maintaining efficiency.

Overview of Noritz Tankless Water Heaters

Noritz tankless water heaters provide efficient, on-demand hot water for homes. These units heat water only as needed, reducing energy costs compared to traditional tank models.

Key Features

Space-Saving Design: Noritz heaters can be mounted on walls, freeing up floor space.
Energy Efficiency: Many models achieve high energy factor (EF) ratings, minimizing energy consumption.
Longevity: Tankless systems last longer than traditional heaters, often exceeding 20 years with proper maintenance.

Operation Mechanism

Noritz systems operate by detecting water flow. When you turn on a tap, the heater ignites a burner, heating the water instantly. This process ensures you get hot water without waiting.

Common Models

NRV Series: Known for high efficiency and compact size, ideal for small spaces.
N-065M: Offers a high flow rate, suitable for larger households needing simultaneous hot water supply.
N-084M: Provides a balance between flow rate and efficiency, perfect for medium-sized homes.

Regular Descaling: Mineral buildup can affect performance. Aim to descale your system every 1-2 years.
Check Venting: Ensure that the venting system remains clear to maintain efficiency and safety.
Annual Inspections: Schedule a professional check-up each year to catch issues early.

Understanding these aspects of Noritz tankless water heaters helps you make informed decisions about maintenance and usage, ultimately enhancing your experience.

Understanding Error Code 51

Error code 51 in Noritz tankless water heaters indicates a problem with the water heater’s ignition or flame detection system. This issue disrupts the proper functioning of the heater, leading to potential water temperature inconsistencies.

What Error Code 51 Indicates

Error code 51 generally signifies that the burner is not igniting or has failed to maintain a flame. This condition can occur due to various reasons, such as:

Flame Sensor Issues: The flame sensor might be dirty or malfunctioning, preventing it from detecting the flame.
Blocked Venting: Obstructions in the venting system can impede airflow, affecting ignition.
Gas Supply Problems: Insufficient gas supply can hinder the burner from lighting properly.

You might encounter this error when attempting to access hot water, signaling that the heater requires immediate attention.

Importance of Addressing Error Codes

Addressing error codes promptly is crucial for maintaining the efficiency and longevity of your Noritz tankless water heater. Ignoring error code 51 can lead to:

Reduced Performance: Prolonged issues may cause the heater to operate inefficiently, resulting in inconsistent water temperatures.
Increased Repair Costs: Persistent problems often necessitate more extensive repairs if left unresolved.
Understanding Operation: Regularly checking error codes enhances your familiarity with the system, allowing you to identify issues sooner and take appropriate action.

Taking immediate action when you encounter error code 51 can prevent further complications and ensure a consistently reliable hot water supply.

Common Causes of Error Code 51

Error code 51 in Noritz tankless water heaters often stems from specific issues that disrupt the ignition or flame detection systems. Understanding these common causes can help you troubleshoot effectively.

Malfunctioning Thermistors

Malfunctioning thermistors can cause significant problems in your water heater. These sensors monitor the water temperature and ensure the unit operates efficiently. If a thermistor fails, it may incorrectly signal to the heater, preventing proper ignition. Regularly test thermistors to confirm they’re functioning correctly. If they show signs of damage or malfunction, replacement is necessary to restore proper operation.

Issues with Water Flow

Issues with water flow can trigger error code 51 as well. Blockages in the water supply line or low water pressure can prevent adequate flow, causing the heater to fail in igniting. Ensure your water supply has consistent pressure and check for obstructions, such as scale buildup in pipes. Clean filters and valves to facilitate proper flow. If you notice ongoing issues, consider evaluating the entire plumbing system for additional problems.

Troubleshooting Error Code 51

Error code 51 signals an issue with your Noritz tankless water heater’s ignition or flame detection system. Here’s a structured approach to address this problem.

Initial Steps to Take

Check Power Supply: Ensure the water heater’s power cord is plugged in securely and the circuit breaker hasn’t tripped.
Inspect Gas Supply: Confirm the gas valve is open and that you have gas supply to the unit.
Reset the Unit: Turn off the heater, wait 30 seconds, then turn it back on. This simple reset can sometimes resolve minor issues.
Examine Water Flow: Ensure that water is flowing adequately to the unit. Check for obstructions in the supply line.

Flame Sensor Cleaning: Remove the flame sensor and gently clean it with fine sandpaper or a soft cloth. A dirty sensor can misread the flame.
Thermistor Testing: Test the thermistor with a multimeter. If it doesn’t give the correct resistance reading, replace it to maintain accurate temperature readings.
Venting Check: Inspect the venting system for blockages or constraints. Clear any debris that could hinder exhaust flow.
Pressure Test: Use a pressure gauge to check water supply pressure. Ideal pressure ranges from 40 to 60 psi. Low pressure requires adjustment or repairs.
Consult the Manual: Refer to your Noritz heater’s manual for model-specific troubleshooting tips. Follow all instructions carefully.

By following these steps, you can efficiently troubleshoot error code 51 and restore your tankless water heater’s performance.

Prevention Tips for Noritz Tankless Water Heaters

Maintaining your Noritz tankless water heater prevents issues like error code 51. Here are some effective strategies to ensure your unit runs smoothly.

Regular Maintenance Practices

Descale the Heater: Descale your unit every six months to remove mineral buildup. This helps maintain efficiency and prevents overheating.
Inspect Filters: Check and clean the inlet water filter regularly. A clogged filter restricts flow and can trigger error codes.
Check Vents: Inspect the venting system for blockages, especially during seasonal changes. Clear vent pipes enhance combustion and prevent ignition failure.
Test Components: Regularly test components like thermistors and flame sensors. Replace any malfunctioning parts immediately to avoid performance issues.
Schedule Professional Inspections: Arrange annual inspections with a qualified technician. Professional assessments catch potential problems early, extending your heater’s lifespan.

Set Optimal Temperature: Adjust the temperature setting between 120°F to 140°F. This range ensures comfort and minimizes energy consumption.
Monitor Water Flow Rates: Be aware of your unit’s maximum flow rate. Avoid running multiple hot water sources simultaneously, which can overwhelm the system.
Control the Gas Pressure: Ensure proper gas supply pressure according to the manufacturer’s specifications. Inadequate pressure can lead to ignition issues.
Utilize the Remote Control: If your model includes a remote control, use it to monitor performance. This tool enables you to make real-time adjustments based on your hot water needs.
Adjust for Weather Changes: During colder months, consider increasing the heater setting to maintain warm water supply.

By implementing these prevention tips, you can enhance your Noritz tankless water heater’s reliability, reducing the likelihood of encountering error code 51.

Conclusion

Dealing with error code 51 in your Noritz tankless water heater can be a hassle but understanding the issue is the first step toward a solution. By taking proactive measures like regular maintenance and troubleshooting, you can keep your system running smoothly and enjoy consistent hot water whenever you need it.

Remember to stay on top of cleaning and inspections to prevent future problems. With a little attention and care, you can ensure your tankless water heater continues to provide the efficiency and reliability you expect. Don’t let error codes disrupt your comfort—address them promptly and keep enjoying the benefits of your Noritz heater.

Frequently Asked Questions

What is error code 51 in Noritz tankless water heaters?

Error code 51 indicates a problem with the ignition or flame detection system in Noritz tankless water heaters. This may result in inconsistent water temperatures or a failure to ignite, leading to cold showers and other issues.

What causes error code 51?

Common causes of error code 51 include malfunctioning flame sensors, blocked venting, gas supply problems, and issues with thermistors or water flow. Any of these issues can disrupt the heater’s operation and should be addressed promptly.

How can I troubleshoot error code 51?

To troubleshoot error code 51, start by checking the power and gas supply, resetting the unit, and examining water flow. Clean the flame sensor, test the thermistor, and check for venting blockages. Consult your heater’s manual for specific guidance.

How can I prevent encountering error code 51?

To prevent error code 51, perform regular maintenance like descaling every six months, cleaning filters, inspecting venting systems, and testing components like thermistors. Schedule annual inspections with a technician and monitor water flow rates and gas pressure.

What should I do if the problem persists?

If issues persist after troubleshooting and preventive measures, consider contacting a qualified technician to conduct a thorough evaluation of your Noritz tankless water heater and plumbing system. Professional help can identify complex problems quickly.

Jake Newman

Jake Newman is Appliance Mastery’s expert on refrigeration and cooling systems. With over a decade of experience in the appliance repair industry and certification from NASTeC, Jake is a trusted source of knowledge for homeowners who want to troubleshoot and repair their fridges, freezers, and air conditioning units.

Noritz Tankless Water Heater Error Code 51: Troubleshooting Tips to Restore Hot Water Flow