Ever had a cold shower because your Noritz tankless water heater stopped working? You’re not alone. Error codes 14 and 90 can really mess up your day and leave you wondering what’s wrong.
Noritz error codes are like secret messages that tell you something’s off with your water heater. They might mean a thermal fuse problem or an issue with how it burns fuel. Knowing what these codes mean can save you time, money, and stress.

I’ll explain the most common problems with Noritz tankless water heaters. This will help you figure out and maybe fix these issues before they get worse.
Understanding Noritz Error Code System Basics
Dealing with common Noritz tankless water heaters can be tough, thanks to those mysterious error codes. Through my heater troubleshooting guide experience, I’ve learned that knowing these codes is key. It keeps your system running well and lasting longer.
Error Code Categories Explained
Noritz error codes are advanced tools for finding problems in your tankless water heater. They usually fall into a few main groups:
- Ignition failures
- Flame sensor malfunctions
- Combustion process interruptions
- Electrical component problems
Read also: Some Common Noritz Error Code
Accessing Error Code History
Most home Noritz remote controllers let you see error code history easily. Here’s how to check your unit’s diagnostic log:
- Press the information or diagnostic button on your remote
- Navigate to the error log section
- Review recent error codes and their timestamps
Critical Safety Precautions
Always put safety first when fixing your tankless heater. Here are some must-do safety steps:
- Turn off the gas supply completely
- Disconnect electrical power to the unit
- Allow the system to cool down
- Wear protective equipment
Knowing these basics about error codes will help you tackle tankless water heater problems with confidence and skill.
Error Code 14: Thermal Fuse Failure Detection
Seeing error code 14 on your Noritz tankless water heater means there’s a serious thermal fuse failure. This error shows the heat exchanger might be overheating. This could harm the whole system’s safety and function.
It’s key to know why you’re seeing error code 14 for good gas heater upkeep. The thermal fuse is a safety guard. It keeps your water heater from getting too hot.
- Primary triggers for Error Code 14:
- Restricted airflow in combustion chamber
- Compromised gas burning processes
- Heat exchanger blockages
To fix your Noritz heater after error code 14, you must look into common heater problems. Taking the right steps can stop lasting damage to your unit.
Diagnostic Area | Potential Problem | Recommended Action |
---|---|---|
Heat Exchanger | Scale or sediment buildup | Professional cleaning or replacement |
Thermal Fuse | Electrical failure | Direct replacement |
Combustion Airflow | Blocked ventilation | Clear obstructions, check venting |
If you can’t figure out or fix the error code yourself, you need a pro. Regular upkeep can lower the chance of thermal fuse failures in your Noritz tankless water heater.
Causes and Solutions for Error Code 90 Combustion Issues
Error Code 90 is a serious problem with your water heater’s combustion. It means your heating system is not working right. This could stop you from having hot water at home.

This error code shows up after three tries to heat the water to the right temperature. Knowing why it happens helps fix your tankless water heater.
Gas Pressure Problems
Low gas pressure or wrong settings cause Error Code 90. To find out why, look at these possible problems:
- Insufficient external gas line pressure
- Blocked gas valve or regulator
- Incompatible gas type for your water heater model
Air Supply Complications
Good air flow is key for your water heater. Check for air blockages when troubleshooting:
- Obstructed intake or exhaust vents
- Improper ventilation installation
- Accumulated debris around air intake areas
Flame Sensor Malfunctions
The flame sensor checks if the heater is burning right. Dirt, corrosion, or being off can cause Error Code 90:
- Clean flame sensor regularly
- Check for physical damage
- Verify proper sensor positioning
Error Code 90 Possible Causes | Recommended Action |
---|---|
Low Gas Pressure | Contact gas utility or professional technician |
Blocked Vents | Clear intake and exhaust pathways |
Dirty Flame Sensor | Clean or replace sensor |
Some fixes you can do yourself, but complex problems need a pro. Noritz customer service can help with tough issues.
Noritz Tankless Water Heater Troubleshooting
Fixing a Noritz tankless water heater needs a step-by-step plan. Knowing the error codes helps you find and fix problems fast.
Here are the basic steps to troubleshoot your Noritz tankless water heater:
- Check all gas and water connections for leaks or loose fittings
- Look at the venting system for blockages or damage
- Make sure electrical connections are tight and not damaged
- Check the flame sensor for dirt or buildup
Common error codes you might see include:
Error Code | Potential Issue | Recommended Action |
---|---|---|
11 | Ignition Failure | Check gas pressure and air supply |
12 | Flame Loss | Inspect flame sensor and clean if necessary |
16 | Overheat Protection | Descale system and check water quality |
If you face complex issues, check the Noritz manual or call a licensed heating expert. Some problems need special tools or skills that homeowners can’t handle.
Regular upkeep is vital to avoid most problems. Getting a professional to check your system yearly can prevent big repairs.
Preventive Maintenance Tips to Avoid Error Codes
Keeping your Noritz tankless water heater in good shape is key. It helps avoid error codes and keeps your water heater running well. Regular care also saves money and makes your water heater last longer.

Regular maintenance stops problems before they start. By taking care of your tankless water heater, you avoid unexpected breakdowns and expensive fixes.
Regular Cleaning Schedule
- Flush the tankless water heater every six months with a descaling solution
- Clean the water filter monthly to prevent sediment buildup
- Check for mineral deposits that can impact water heater efficiency
Component Inspection Guidelines
- Inspect gas connections for any signs of wear or leakage
- Examine the venting system for blockages or damage
- Test electrical components for proper functioning
- Look for any corrosion or rust on internal parts
Professional Maintenance Requirements
While you can do some maintenance yourself, getting a pro to check your water heater once a year is a good idea. Experts can:
- Perform thorough system checks
- Deep clean hard-to-reach spots
- Adjust gas and electrical settings
- Find problems before they get big
Regular maintenance can cut down on up to 50 percent of water heater problems. A well-kept Noritz tankless water heater will give you hot water for many years.
Read also: Advantage Of A Tankless Water Heater
Essential Tools and Safety Equipment for DIY Repairs
When you start troubleshooting your heater, the right tools are key. Safety is the most important thing when working with heating systems.
- Multimeter for electrical checks
- Gas pressure gauge
- Adjustable wrench
- Screwdriver set (flathead and Phillips)
- Pipe wrench
When doing DIY repairs, safety gear is a must. Make sure you have:
- Heat-resistant work gloves
- Safety glasses
- Gas leak detector
- Respirator mask
- Fire extinguisher
Always check your Noritz manual before starting repairs. Each model has its own tool needs and safety rules. If you’re not sure, it’s best to call a pro.
Pro tip: Keeping your tankless water heater in good shape can boost its efficiency by up to 30%. Good tools and safety habits save money and prevent dangers.
When to Contact a Professional Technician
When you’re troubleshooting your Noritz tankless water heater, some problems need a pro’s touch. Knowing when to call a technician can save you time, money, and prevent damage to your system.
Some tankless heater fixes are best left to the experts. Here are the situations where you should seek professional help:
- Multiple error codes showing up at once
- Water heater issues that keep coming back after resets
- Complicated gas valve or electrical system problems
- Issues with the neutralizer or combustion system
- Any safety concerns or if you’re not sure how to fix it
Professional technicians have the right tools and know-how to tackle tough water heater problems. They can spot and fix complex issues that might look simple but need advanced skills.
Here are some specific situations that call for a pro:
- Error code 71: This means there’s a big problem with the gas valve.
- Error code 92: This code points to a failure in the neutralizer system.
- Recurring error codes that reset fixes can’t solve.
While fixing things yourself might seem cheaper, it can void your warranty and lead to bigger costs. Experts do thorough checks, fix things right, and follow the manufacturer’s rules.
Common Mistakes to Avoid During Troubleshooting
Many homeowners make big mistakes when fixing their heaters. These errors can turn a simple fix into a big problem. Knowing how to check water flow can save you a lot of time, money, and stress.
I’ve seen many DIY repairs go wrong. Here are the main mistakes to avoid with your Noritz tankless water heater:
- Ignoring Safety Precautions
- Never work on the heater without shutting off gas and electrical connections
- Always wear protective gear
- Ensure proper ventilation during inspections
- Misinterpreting Error Code Meaning
- Don’t guess what an error code represents
- Consult the manual or professional technician
- Research specific error codes before attempting repairs
Working on tankless water heaters can be dangerous. Resetting the unit without knowing why can harm its parts.
Mistake | Potential Consequences |
---|---|
Ignoring Maintenance | Increased risk of system failure |
Improper Tool Usage | Potential damage to sensitive components |
Skipping Professional Inspection | Undetected serious issues |
My advice? If you’re unsure, call a certified technician. Some fixes need special skills and tools that homeowners don’t have.
- Know your limits
- Keep maintenance records
- Schedule regular professional inspections
Conclusion
Dealing with Noritz tankless water heater error codes can be tough. But, with the right steps, you can handle most problems. Knowing about error codes like 14 and 90 is key to keeping your unit working well.
Regular upkeep is vital to avoid most issues. I suggest flushing your unit with white vinegar twice a year. Also, watch for any error signs closely. Always check the basics first and look at your manual before taking more steps.
Your safety is most important when facing error codes. If you’re not sure about anything, call a professional technician. They can solve problems that might confuse you.
Learning about your Noritz tankless water heater is worth it. These units provide endless hot water and can cut down your energy bills. Remember, knowing how to care for your water heater is your best ally for a smooth and efficient operation.