Noritz Tankless Error Codes Troubleshooting

Having a steady stream of hot water whenever you want is fantastic. However, what happens when your tankless water heater throws you an error code? That’s where our guide to Noritz tankless error codes comes in.

Some of you might be handy enough to fix minor issues with your water heater yourself. Knowing how to decipher the error codes and troubleshoot the issue might save you an expensive service call out.

Let’s look at the Noritz error codes, what they mean, and what the solutions are.

Table of Contents

    Where Do I Find the Error Code?

    Noritz water heaters come with a remote controller for operation. You can use it to set the temperature of your water, turn your water heater on and off, and set the flow meter alarm.

    The display on the remote controller is where you’ll find an error code when something needs attention. The number will flash where you’d typically see the temperature.

    Noritz Tankless Error Codes and Troubleshooting

    BE SAFE

    Troubleshooting error codes on a tankless water heater involves dealing with electricity and gas. For safety reasons, make sure you turn the power and gas off when carrying out any maintenance. If you’re unsure about what you are doing, call a professional technician.

    Error Code 05

    What It’s Telling You

    • This is a service warning.

    The Solution

    1. This automatic reminder tells you that your water heater is ready for a service by a qualified Noritz technician. You should not attempt to reset this error code before the service is carried out. Doing so could cause your water heater to fail.

    Error Code 10

    What It’s Telling You

    • The power has dropped, or gas combustion is still happening after the unit has been turned off.

    The Solution

    1. Check the burner for debris: Things like oil or grease might carry on burning after the gas combustion has stopped.
    2. Clean the burners: Wipe off any debris.
    3. Reset: Turn the unit off. Wait 30 seconds. Turn it back on.

    Error Code 11

    What It’s Telling You

    • There’s an ignition failure.

    The Solution

    1. Gas pressure: Make sure it’s in line with your owner’s manual and that the supply is open.
    2. Inspect for blockages: Look at the vents to see if anything is preventing airflow.
    3. Ignition rod: Make sure it’s free from debris or foreign materials.
    4. Wiring to the ignition: Ensure it’s not loose or damaged.

    Error Code 12

    What It’s Telling You

    • The flame is too low and not sufficient to heat the water.

    The Solution

    1. Airflow: Make sure there are no blockages preventing combustion.
    2. Flame rod/sensor: Clean any debris.
    3. Replace the flame rod: If it can’t be cleaned or is faulty.
    4. Adjust the air flow or gas valve: This will help create a sufficient flame.

    Error Code 14

    What It’s Telling You

    • Failure of the thermal fuse.

    The Solution

    1. Thermal fuse: This may have burnt out. Put a new one in.
    2. Blockages in the airflow: Make sure there are no obstructions in the airflow, and the gas has proper combustion.
    3. Heat exchanger: Inspect to see it hasn’t become clogged by sediment.
    4. Flush: Follow the manufacturer’s recommendations to flush the heat exchanger.

    Error Code 16

    What It’s Telling You

    • The water temperature has had a sudden spike and is too high.

    The Solution

    The most common cause of this is a build-up of scale in the system, often the result of hard water (1).

    1. Descale the unit: Do this using vinegar, according to the manufacturer’s instructions.
    2. Reset the code: Following a descale, disconnect the unit. Wait 20 seconds and reconnect.

    Error Code 20

    What It’s Telling You

    • The high limit switch that initiates the thermostat cut off has been activated.

    The Solution

    1. Replace the high limit switch: Examine the switch and replace it if damaged.
    2. Descale the unit: Follow your user manual to descale your unit.

    Error Code 29

    What It’s Telling You

    • The water level has exceeded where it should be because the water level neutralizer is not draining correctly.

    The Solution

    1. Examine the drain line: Make sure there’s no condensate or obstructions and that it’s appropriately routed.
    2. Check the condensate piping: Verify it’s the right size and is sloped correctly.

    Error Code 31

    What It’s Telling You

    • The cold water thermistor on the inlet pipe has failed.

    The Solution

    1. The sensors in the thermistor have failed. Put a new one in.

    Error Code 32

    What It’s Telling You

    • The hot water thermistor on the outlet pipe has failed.

    The Solution

    1. The sensors have failed. Put a new thermistor in.

    Error Code 33

    What It’s Telling You

    • The thermistor on the heat exchanger has failed.

    The Solution

    1. The sensors have failed. Replace this component.

    Error Code 59

    What It’s Telling You

    • The BTU (British thermal unit) input from the gas is low, causing issues with combustion.

    The Solution

    1. Check the gas pressure: Make sure the pressure for the gas is correct and appropriately set for the water heater and its position. Your owner’s manual will tell you the correct settings.
    2. Check the vents: Inspect the vents to the combustion chamber for blockage and airflow.
    3. Clean the burner chamber and the fan motor: Ensure there’s no debris on these components and clean them if necessary.

    Error Code 61

    What It’s Telling You

    • The fan motor has failed.

    The Solution

    1. Is the voltage correct? Check the voltage coming into the fan motor.
    2. Replace the circuit board: If insufficient voltage, replace the circuit board.
    3. Replace the fan motor: If sufficient voltage, replace the fan motor.

    Error Code 65

    What It’s Telling You

    • The main flow control valve has failed.

    The Solution

    1. Obstructions: Check for any blockages in vents and remove them.
    2. Main control valve: Replace this part.

    Error Code 66

    What It’s Telling You

    • There has been a failure of the bypass control valve.

    The Solution

    1. Obstructions: Check for any blockage in the valve.
    2. Renew: Replace the valve if needed.

    Error Code 67

    What It’s Telling You

    • Abnormality in the air-gas mixer (AGM).

    The Solution

    1. Cut the power: Turn the water heater off and on.
    2. Error code reappearance: If the error code is still there, replace the air-gas mixer.

    Error Code 70

    What It’s Telling You

    • The circuit board has failed.

    The Solution

    1. Change out the circuit board for a new one.

    Error Code 71

    What It’s Telling You

    • There’s something wrong with the gas valve drive circuit.

    The Solution

    1. Check the voltage is correct for the unit. This error often happens if the heater is powered by a generator or battery backup, or there’s been a power surge or voltage change. Installing a power surge protector can help.

    Error Code 72

    What It’s Telling You

    • There’s something wrong with the flame rod detection.

    The Solution

    1. Proper grounding: Check the heater is adequately grounded.
    2. Damage: Ensure the flame detection circuit, circuit board, and wires are not damaged.
    3. Renew: Replace any damaged parts.

    Error Code 73

    What It’s Telling You

    • The circuit board isn’t set correctly.

    The Solution

    This could be the result of improper programming or changing a dip switch or jumper connection with the power on.

    1. Cut the power: Unplug the heater for 30 seconds.
    2. Return the power: Plug it back in and turn it on.
    3. Error code still shows: If the code persists, call out a qualified technician.

    Error Code F76

    What It’s Telling You

    • This indicates an error in communication between heaters when you have more than one, and they’re connected with a quick connect cord. More than one remote hooked up to the units can cause a malfunction.

    The Solution

    1. Check the remote controls: Ensure only one remote control is operating for multiple heaters connected.
    2. To reset the code: Unplug the units for 30 seconds and then power them back up.

    Error Code 760

    What It’s Telling You

    • There’s a problem with the remote control.

    The Solution

    1. Is the wiring good? Check the unit for loose wires.
    2. Check the remote controls: Make sure only one remote is connected to multiple heaters.
    3. Reset the code: Unplug the heater for 30 seconds then plug it in again.

    Error Codes 90 and 91

    What They’re Telling You

    • Abnormality in the gas combustion.

    The Solution

    1. Blockages: Check for any obstruction in airflow or gas flow.
    2. Correct air/gas mix: Make sure the combination of the gas/air mix is in line with your owners manual.
    3. Check for debris: Ensure there’s no dirt in the fan motor or fuel vents.

    Error Codes 92 and 93

    What They’re Telling You

    • The neutralizer has reached the end of its lifecycle.

    The Solution

    1. Replace the neutralizer: Put in a new one according to your owner’s manual.
    2. Reset the burner timer: Follow the instructions in your owner’s manual.

    Errored Out

    As you can see, there are lots of little things that can go wrong with a Noritz water heater. They don’t happen that frequently but need attention when they do.

    Many of them are quick fixes you can carry out yourself, provided you feel confident enough. If you have any doubts, call out a licensed service technician to sort the issue out for you.

    We hope you enjoyed our tips on troubleshooting Noritz tankless error codes. Did any of them work for you? Please leave us a comment with your thoughts and don’t forget to share this article!

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