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Noritz Error Codes

Noritz - Tankless Water Heater Error Codes

Error Code
Description

Error Code 05

Service Warning- It’s time to schedule service. Do not reset the error code prior to the service or the water heater may prematurely fail.

Error Code 10

Power Drop or Gas Combustion continues after the unit is shut off.   Look for foreign materials (ie: oil or grease) on the burner which are still burning after gas combustion stops. To reset the code, turn the unit off and then on. 

Error Code 11

Ignition failure. Check 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. 

Error Code 12

The 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.

Error Code 14

The thermal fuse has failed. Replace 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 get clogged. Flush the heat exchanger if necessary.

Error Code 16

Water temperature is too high.  Since this is most often caused by hard water or scale buildup, a descaling procedure should be performed. To reset the code afterwards, unplug the water heater for 20 seconds and plug it back in.

Error Code 20

High limit switch has been activated. Check the high limit switch and replace if necessary. Otherwise, perform the descaling procedure.

Error Code 29

Water level in the neutralizer is not properly draining making the water level exceed the correct level.  Make sure the condensate drain line is properly routed and unobstructed. Confirm condensate piping is the correct size and properly sloped

Error Code 31

Inlet (cold water) thermistor failure. Replace inlet thermistor.

Error Code 32

Outlet (hot water) thermistor failure. Replace outlet thermistor.

Error Code 33

 Heat exchanger thermistor failure. Replace the heat exchanger thermistor.

Error Code 45

Water leak.  Close the water inlet valve and call for service if you notice a leak. If no visible leak, unplug the unit for 30 seconds to reset it and see if the code clears itself.

Error Code 59

Low gas BTU input causing combustion problems. Confirm correct gas pressure set and properly set for elevation where it’s 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.

Error Code 61

Fan motor failure. Check voltage coming to the fan motor. Replace fan motor or circuit board if necessary.

Error Code 65

Main flow control valve failure. Check for blockage and replace the main flow control valve if necessary.

Error Code 66

Bypass flow control valve failure. Check for blockage and replace the bypass flow control valve if necessary.

Error Code 67

AGM (Air Gas Mixer) abnormality.  Turn the unit off then on. If the code reappears, the air gas mixer will likely need to be replaced

Error Code 70

Circuit board failure. Replace circuit board

Error Code 71

Abnormality in gas valve drive circuit.  Confirm 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.

Error Code 72

Flame rod detection abnormality. Confirm that the water heater is properly grounded. Check for a damaged circuit board, flame detection circuit, or wires, and replace if necessary.

Error Code 73

Improper circuit board setting. Most 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 a licensed service tech.

Error Code 90  & 91

Gas combustion abnormality.  Check airflow obstruction and improper gas burning. Confirm correct air/fuel mixture and gas pressure. Once fixed, reset the unit by unplugging for 30 seconds.

Error Code  92 & 93

Neutralizer is at the end of its life cycle. Replace neutralizer and reset burner timer.

Error Code 99

Abnormal Combustion. Call or Text Blue Conservation’s trained Navien specialists at 484-469-0718.

Error Code 760

Remote controller problem. Check for loose wires and confirm only one remote is connected to the water heater. Unplug the unit for 30 seconds to reset.

Error Code 902

Abnormal Combustion  Have a professional check the gas supply pressure. Call or Text Blue Conservation’s trained Navien specialists at 484-469-0718.

Error Code 903 & 908

Abnormal combustion.  Confirm nothing is obstructing the intake or exhaust pipe.

Error Code 941 & 942

Exhaust temperature is too high.  Check for and clear any air blockages and reset unit. If that doesn’t work, call a licensed service tech. 

Error Code F76

Communication error between two tankless water heaters using Quick Connect cord. Confirm 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.

Error Code CF1, Error Code CF2, Error Code CF3, Error Code CF4

The unit detects scale build-up in the Heat Exchanger.  Flush the heat exchanger in accordance with the process in the Owner’s Manual.

Error Code CF1, Error Code CF2, Error Code CF3, Error Code CF4, Error Code CF5, Error Code CF6, Error Code CF7, Error Code, CF8, Error Code CF9, Error Code CFA, Error Code CFb, Error Code CFC, Error Code CFd, Error Code CFE, Error Code CFF

The unit detects the scale build-up in the Heat Exchanger many times and the unit is locked.  Call or Text Blue Conservation’s trained Navien specialists at 484-469-0718 and see How to Fix: Flush the heat exchanger in accordance with the process in the Owner’s Manual.