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Error Codes · Noritz

Noritz Tankless Water Heater Error Codes

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← All Tankless Error Codes

Blue Conservation’s trained Noritz specialists can help diagnose error codes, flush heat exchangers, and restore hot water quickly. Record your code and contact us with your unit information.

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Noritz Units Covered

Error codes below apply to the models listed. Newer or discontinued models may not be shown.

Residential Tankless—Condensing Models

NRCR, NRCR111, NRCR92, NRCR Pro Series, EZ, EZTR40, EZTR50, EZTR75, EZ71DV, EZ98DV, EZ111DV, NRC663, NRC711, NRC98, NRC111, NCC199CDV, NCC199OD, NCC199DV

Combi-Boilers

NRCB180, NRCB199, NRCB Combination Boiler Series

Residential Non-Condensing Models

NR50, NR66, NR71, NR83, NR98, NR111, NC199, NC250

Blue Conservation recommends contacting a licensed and trained service technician for troubleshooting and repairs. The information below is presented for informational purposes only, not as guidance or instruction. Customers who remove the cover from any equipment do so at their own risk and responsibility. For service and assistance, please contact Blue Conservation at 484-469-0718 during regular business hours. For members of our Blue Club service plan, feel free to call or text service requests at any time and we will look to respond as soon as possible.

Noritz Tankless Water Heater Error Codes

If your unit is locked due to repeated scale buildup (CF codes), contact Blue Conservation for professional service.
ManufacturerError CodeDescription
NoritzError Code 05Service WarningIt’s time to schedule service. Do not reset the error code prior to the service or the water heater may prematurely fail.
NoritzError Code 10Power Drop or Gas Combustion continues after the unit is shut off Look for foreign materials (i.e., oil or grease) on the burner that are still burning after gas combustion stops. To reset the code, turn the unit off and then on.
NoritzError Code 11Ignition failureCheck the gas pressure for correct values. Look for any obstructions in the vents as the fresh air supply might be being blocked. Remove any foreign materials from the ignition rod. Confirm there is no loose wiring in the ignition.
NoritzError Code 12The tankless unit has a weak flame and the water is not being properly heated Confirm that there is enough airflow for proper gas combustion. Check that the flame rod/sensor is not covered by debris. Clean or replace if necessary.
NoritzError Code 14The thermal fuse has failedReplace the thermal fuse. Confirm that the unit has no airflow restrictions and gas has proper combustion. Check water quality, as hard water or sediment can cause the heat exchanger to become clogged. Flush the heat exchanger if necessary.
NoritzError Code 16Water temperature is too highSince this is most often caused by hard water or scale buildup, a descaling procedure should be performed. To reset the code afterward, unplug the water heater for 20 seconds and then plug it back in.
NoritzError Code 20High-limit switch has been activatedCheck the high-limit switch and replace if necessary. Otherwise, perform the descaling procedure.
NoritzError Code 29Water level in the neutralizer is not properly draining, causing the water to exceed the correct levelMake sure the condensate drain line is properly routed and unobstructed. Confirm condensate piping is the correct size and properly sloped.
NoritzError Code 31Inlet (cold water) thermistor failureReplace inlet thermistor.
NoritzError Code 32Outlet (hot water) thermistor failureReplace outlet thermistor.
NoritzError Code 33Heat exchanger thermistor failureReplace the heat exchanger thermistor.
NoritzError Code 45Water leakClose the water inlet valve and call for service if you notice a leak. If there is no visible leak, unplug the unit for 30 seconds to reset it and see if the code clears itself.
NoritzError Code 59Low gas BTU input causing combustion problemsConfirm correct gas pressure as well as gas settings for elevation where it is installed. Make sure enough airflow is getting to the combustion chamber by removing any noticeable blockage of the vents. Clean fan motor and burner chamber.
NoritzError Code 61Fan motor failureCheck voltage coming to the fan motor. Replace fan motor or circuit board if necessary.
NoritzError Code 65Main flow control valve failureCheck for blockage and replace the main flow control valve if necessary.
NoritzError Code 66Bypass flow control valve failureCheck for blockage and replace the bypass flow control valve if necessary.
NoritzError Code 67AGM (
Air Gas Mixer) abnormalityTurn the unit off then on. If the code reappears, the air gas mixer will likely need to be replaced.
NoritzError Code 70Circuit board failureReplace circuit board.
NoritzError Code 71Abnormality in gas valve drive circuitConfirm correct voltage. This error code is often seen when a unit is connected to a generator or battery backup or if there is another type of voltage fluctuation. Install a power surge protector if necessary.
NoritzError Code 72Flame rod detection abnormalityConfirm that the water heater is properly grounded. Check for a damaged circuit board, flame detection circuit, or wires, and replace if necessary.
NoritzError Code 73Improper circuit board settingMost likely a jumper connection or dip switch was changed on the circuit board while under power, or the circuit board was improperly programmed. Unplug the unit for 30 seconds and plug back in. If the error code still shows up, call or text Blue Conservation’s trained Noritz specialists at 484-469-0718
NoritzError Code 90and 91Gas combustion abnormalityCheck airflow obstruction and improper gas burning. Confirm correct air/fuel mixture and gas pressure. Once fixed, reset the unit by unplugging for 30 seconds.
NoritzError Code 92and 93Neutralizer is at the end of its life cycleReplace neutralizer and reset burner timer.
NoritzError Code 99Abnormal CombustionCall or text Blue Conservation’s trained Noritz specialists at 484-469-0718.
NoritzError Code 760Remote controller problemCheck for loose wires and confirm only one remote is connected to the water heater. Unplug the unit for 30 seconds to reset.
NoritzError Code 902Abnormal Combustion Have a professional check the gas supply pressure. Call or text Blue Conservation’s trained Noritz specialists at 484-469-0718.
NoritzError Code 903and 908Abnormal combustionConfirm nothing is obstructing the intake or exhaust pipe.
NoritzError Code 941and 942 Exhaust temperature is too highCheck for and clear any air blockages and reset unit. If that doesn’t work, call or text Blue Conservation’s trained Noritz specialists at 484-469-0718.
NoritzError Code F76Communication error between two tankless water heaters using Quick Connect cordConfirm that only one remote control is hooked up when multiple units are connected together. Unplug the unit for 30 seconds and plug back in to reset it.
NoritzError Code CF1,
NoritzError Code CF2,
NoritzError Code CF3,
NoritzError Code CF4The unit detects scale buildup in the Heat ExchangerFlush the heat exchanger in accordance with the process in the owner’s manual.
NoritzError Code CF1,
NoritzError Code CF2,
NoritzError Code CF3,
NoritzError Code CF4,
NoritzError Code CF5,
NoritzError Code CF6,
NoritzError Code CF7,Error Code, CF8,
NoritzError Code CF9,
NoritzError Code CFA,
NoritzError Code CFb,
NoritzError Code CFC,
NoritzError Code CFd,
NoritzError Code CFE,
NoritzError Code CFFThe unit detects scale buildup in the heat exchanger many times and the unit is lockedCall or text Blue Conservation’s trained Noritz specialists at 484-469-0718 and see “How to Fix: Flush the Heat Exchanger” in accordance with the process in the owner’s manual.

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We’re Here to Help

Emergency Response

Blue Conservation often troubleshoots error codes over the phone, and we do our best to respond as quickly as possible to emergency requests. Response times will vary depending on the nature of the malfunction, time of day (or night), and personnel availability, but we take pride in our customer service and satisfaction.

BLUE CLUB MEMBERS ALWAYS GET PRIORITY SERVICE! Let us know if you are a Blue Club member—members receive priority and expedited services. Learn about Blue Club →

If you are experiencing a boiler, combi, or tankless water heater emergency, text us right away at 484-469-0718.

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Please Include the Following Information

Name and address, including email
Equipment make and model
Description of the problem and any error codes being displayed
Photos of the error code display
Let us know if you are a Blue Club member! Members receive priority and expedited services.

Text Us With the Correct Information

Have your Noritz make, model, and error code ready. Text 484-469-0718 or request service online.

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I thought I was truly in a pickle when my furnace went out around the holidays, and I felt so ridiculous for not having had it serviced in the fall. But Jim got right back to me, and an expert technician came right out, listened to my questions and concerns, and came up with great solutions immediately

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Ready to Select and Install Your Tankless Water Heater?

Email service@blueconservation.com or text 484-469-0718 to request a quote or request service. A knowledgeable Blue Conservation team member will help with equipment selection, estimates, and installation scheduling.

Reach Out Anytime We’re Here to Help

484-469-0718
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