Navien tankless water heaters are a fantastic investment for endless hot water, but when an error code flashes, it can be puzzling. Don’t panic! This comprehensive guide will help you understand, diagnose, and often resolve common Navien error codes, getting your hot water flowing again.

Understanding Your Navien Error Codes: What Do They Mean?

Navien error codes are displayed on your unit’s control panel and typically consist of letters and numbers (e.g., E001, E012). Each code signifies a specific problem within the system, guiding you toward the right solution.

Before You Begin: Safety First!

• Turn off the power: Always disconnect power to your Navien unit at the breaker before attempting any internal repairs or inspections.
• Turn off the gas supply: If your unit is gas-powered, ensure the gas valve is closed.
• Consult your manual: Your specific Navien model’s user manual is an invaluable resource. It will have a detailed list of error codes and troubleshooting steps unique to your unit.
• When to call a professional: Many advanced error codes and repairs involve gas, electrical, or complex mechanical systems. If you’re unsure, uncomfortable, or if the issue persists after basic troubleshooting, always call a Navien-certified technician. Attempting repairs beyond your skill level can be dangerous and may void your warranty.

Common Navien Error Codes and Troubleshooting Steps

Here’s a breakdown of frequently encountered Navien error codes and practical steps you can take:

1. Error Code E001 / 001 / E11: Ignition Failure / No Ignition

This code indicates that the water heater failed to ignite or lost its flame.

Possible Causes:

• Gas supply issues: The gas valve is closed, low gas pressure, or an interruption in the gas supply.
• Blocked or dirty air filter/intake: Insufficient airflow for combustion.
• Faulty igniter or flame rod: Components responsible for igniting the gas.
• Dirty burner: Prevents proper ignition.
• Incorrect DIP switch settings: Less common, but possible after installation or service.

Troubleshooting Steps:

1. Check Gas Supply:
   • Ensure the main gas valve to your house is open.
   • Verify the gas valve directly connected to your Navien unit is fully open.
   • If you suspect low gas pressure, contact your gas utility company.
2. Inspect Air Intake and Exhaust:
   • Check the air intake and exhaust vents outside your home for any obstructions (e.g., leaves, debris, bird nests, snow, ice).
   • Clean the intake air filter inside the unit. It’s usually located near the blower assembly.
3. Reset the Unit: Turn off the power to the unit at the breaker for a few minutes, then turn it back on. This can sometimes clear temporary glitches.
4. Inspect the Flame Rod (Advanced DIY / Professional Recommended):
   • If comfortable, you can visually inspect the flame rod for any signs of soot or damage. A dirty flame rod can often be gently cleaned with fine-grit sandpaper or a soft cloth.
   • Caution: This involves working near gas components. If unsure, call a professional.
5. Professional Help: If the above steps don’t resolve E001, it likely indicates a problem with the igniter, gas valve assembly, or internal wiring. A qualified technician can diagnose and replace these components.

2. Error Code E002 / 002: Overheating / Exhaust Sensor Problem

This code often signifies that the water temperature has exceeded safe limits or there’s an issue with the exhaust sensor.

Possible Causes:

• Blocked heat exchanger: Mineral buildup (scale) can restrict water flow and cause overheating.
• Insufficient water flow: Partially closed water valves, a clogged inlet filter, or a faulty flow sensor.
• Faulty temperature sensor (thermistor): Provides incorrect temperature readings.
• Blocked vent or dirty heat exchanger: Leads to abnormal exhaust temperatures.

Troubleshooting Steps:

1. Check Water Flow:
   • Ensure all main water supply valves to the unit are fully open.
   • Clean the inlet water filter/strainer located on the cold water inlet.
   • If you have an NPE-Advanced model, check the recirculation inlet screen as well.
2. Reset the Unit: Power cycle the unit at the breaker.
3. Descale the Heat Exchanger (DIY if comfortable, otherwise Professional): Mineral buildup (limescale) is a common culprit. This involves circulating a descaling solution through the heat exchanger. Navien recommends annual descaling, especially in hard water areas.
   • You will need a submersible pump, hoses, and a descaling solution (vinegar or commercial).
   • Always follow your unit’s manual for descaling instructions.
4. Professional Help: If the issue persists, the temperature sensor, heat exchanger itself, or other internal components may be faulty. Contact a technician.

3. Error Code E004: False Flame Detection

This error means the unit is detecting a flame when it shouldn’t be, potentially indicating a safety issue.

Possible Causes:

• Faulty flame sensor: Sending incorrect signals to the control board.
• Gas valve leak: Small amounts of gas may be present when they shouldn’t be.
• Circuit board problem: Malfunctioning control board.
• Exhaust or intake blockage: Can lead to improper combustion and false readings.

Troubleshooting Steps:

1. Check Electrical Grounding: Ensure the electrical cord is properly grounded.
2. Reset the Unit: Power cycle the unit.
3. Professional Help: This error often points to a component failure that requires professional diagnosis and replacement of the flame sensor, gas valve, or PCB (control board). Do not attempt to fix a suspected gas leak yourself.

4. Error Code E012: Flame Loss During Operation

Similar to ignition failure, but occurs after the unit has successfully ignited.

Possible Causes:

• Insufficient gas supply/pressure: Gas supply fluctuating or too low.
• Dirty burner or flame rod: Prevents consistent flame.
• Blocked exhaust/intake: Reduces proper combustion.
• Faulty gas valve or regulator.
• Internal leaks.

Troubleshooting Steps:

1. Check Gas Supply: Verify gas valves are fully open and there are no supply interruptions.
2. Inspect Venting: Ensure intake and exhaust are free of obstructions.
3. Clean Flame Rod/Burner (Advanced DIY / Professional): If comfortable, inspect and clean the flame rod and burner assembly.
4. Professional Help: Low gas pressure, a faulty gas valve, or an internal leak will require professional attention.

5. Error Code E016: Water Flow Issue

Indicates an issue with water flow through the unit.

Possible Causes:

• Clogged water filter or inlet screen: Most common cause.
• Partially closed water valves: Restricting flow.
• Faulty flow sensor: Not accurately detecting water movement.
• Mineral buildup in pipes or heat exchanger: Restricting flow.
• Too many hot water demands at once: Unit struggles to meet demand if exceeding its capacity.
• Low incoming water pressure.

Troubleshooting Steps:

1. Check Water Valves: Ensure all water isolation valves (cold water inlet, hot water outlet) are fully open.
2. Clean Water Filter/Strainer: Locate the inlet water filter (usually at the cold water inlet) and clean any debris or sediment.
3. Reset the Unit: Power cycle.
4. Descale the Unit: If the water flow issue is due to mineral buildup, descaling is necessary.
5. Reduce Simultaneous Hot Water Use: If you’re running multiple hot water fixtures, try staggering their use to avoid overwhelming the unit.
6. Professional Help: If cleaning the filter and descaling don’t work, the flow sensor or internal piping may require professional inspection or replacement.

6. Error Code E030: Abnormal Air Pressure / E110: Abnormal Air Pressure

These codes relate to issues with the air pressure within the unit, often tied to ventilation or the fan.

Possible Causes:

• Blocked vent or air intake: Obstructions in the flue or air supply.
• Faulty fan motor: Not providing adequate airflow.
• Air pressure sensor failure.
• Condensate trap issues: Clogged or full condensate trap can affect air pressure.

Troubleshooting Steps:

1. Check Venting: Inspect intake and exhaust pipes for any blockages (ice, snow, debris, animal nests).
2. Clean Intake Air Filter: Ensure it’s not clogged with dust or lint.
3. Clean Condensate Trap: The condensate trap is usually at the bottom of the unit. Remove, clean, and re-install it, ensuring the O-ring is properly seated.
4. Professional Help: Fan motor issues, air pressure sensor failures, or persistent venting problems require a qualified technician. These are often crucial for safe operation.

7. Error Code E046: Abnormal Operation: Limit Control / E047: Abnormal Operation: Exhaust Thermostat

These codes indicate safety limits have been tripped due to abnormal temperatures.

Possible Causes:

• Overheating: Similar to E002, likely due to restricted water flow or scale buildup.
• Faulty sensors: The limit control or exhaust thermostat itself may be malfunctioning.

Troubleshooting Steps:

1. Turn Off Unit and Wait: Allow the unit to cool down completely (at least 30 minutes) before attempting a restart.
2. Clean Inlet Water Filter and Strainer.
3. Check Heat Exchanger for Clogs (Professional Recommendation).
4. Professional Help: These are often safety shutdowns and require a technician to diagnose the root cause and ensure proper operation.

8. Error Code E060: Abnormal Operation: Dual Venturi / E109: Abnormal Operation: Fan Motor

These codes point to issues with the combustion air system.

Possible Causes:

• Fan motor malfunction: The fan isn’t spinning correctly or at the right speed.
• Blocked intake/exhaust: Restricting proper airflow for the fan.
• Dual Venturi issues: Problems with the component that mixes air and gas for combustion.

Troubleshooting Steps:

1. Check Intake/Exhaust for Obstructions.
2. Clean Intake Air Filter.
3. Professional Help: These often require testing and potential replacement of the fan motor or Dual Venturi by a qualified technician.

9. Error Code E760: Time to Flush Your Water Heater

This is not an error but a maintenance reminder. Your Navien unit is telling you it’s time for its annual descaling.

Solution:

• Perform a thorough descaling/flushing of your unit. You can do this yourself if you have the proper equipment (pump, hoses, descaling solution) and follow your manual, or hire a professional. Regular descaling prevents many of the issues that lead to error codes like E002 and E016.

General Maintenance Tips to Prevent Navien Error Codes

Proactive maintenance can significantly reduce the likelihood of encountering error codes:

• Annual Descaling/Flushing: This is the most crucial maintenance step, especially in areas with hard water. It removes mineral buildup that can clog the heat exchanger and other components.
• Regularly Clean Filters: Keep the inlet water filter and air intake filter clean to ensure proper water and air flow.
• Check Condensate Trap: Clean the condensate trap periodically to prevent blockages.
• Inspect Venting: Ensure intake and exhaust pipes are free of obstructions.
• Professional Tune-Up: Consider having a certified Navien technician perform an annual inspection and tune-up. They can identify potential issues before they become major problems.
• Monitor Water Pressure: Ensure your home’s water pressure is within the recommended range for your Navien unit.

When to Call a Professional Navien Technician

While some troubleshooting can be done by homeowners, many Navien error codes and underlying issues require specialized knowledge, tools, and experience. Always call a professional for:

• Any error code involving gas (e.g., E001, E004, E012) if basic checks don’t resolve it. Gas leaks or combustion issues are serious safety hazards.
• Persistent error codes: If a code reappears shortly after you clear it.
• Issues related to electrical components: PCB (control board), igniter, sensors.
• Leaks: Any water or gas leaks from the unit.
• Unusual noises or smells.
• Repairs involving internal components you’re not familiar with.
• If you’re uncomfortable or unsure at any point.

A certified Navien Service Specialist (NSS) will have the training and diagnostic tools to accurately identify the problem and perform safe, effective repairs, often preserving your warranty.