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ErrBase

Noritz Waterheater Error Codes

All Noritz waterheater error codes with step-by-step troubleshooting, multimeter specs, and OEM part numbers.

14 error codes

CodeMeaning
11The unit attempted ignition three times and could not establish a flame. No flame signal was detected by the flame rod during any attempt.
highintermediate
12The flame rod detected that the burner flame was lost after successful ignition. The unit established a flame but it extinguished before the call for hot water ended.
highintermediate
14The thermal fuse, a one-time safety device in the heat exchanger circuit, has blown due to excessive heat. The unit will not operate until the fuse is physically replaced by a technician.
criticaladvanced
16The gas pressure sensor or combustion monitoring system detected that gas supply pressure is outside the acceptable operating range, or that combustion is abnormal due to pressure issues.
highintermediate
20The combustion fan (blower motor) has failed, stalled, or cannot reach the required operating speed. The unit cannot run without the fan providing combustion air and evacuating exhaust gases.
highadvanced
29The heat exchanger temperature sensor detected a temperature exceeding the safe operating threshold (160 to 180 degrees F). The unit shut down to prevent damage.
highintermediate
90The combustion sensor detected abnormal combustion. Most commonly caused by exhaust gases recirculating back into the air intake, producing oxygen-depleted combustion air.
highintermediate
CONDENSATE-DRAINCondensing Noritz units (NRCP series) extract extra heat from flue gases, producing acidic condensate that must drain continuously. A blocked or frozen condensate drain causes unit shutdown and can trigger Code 29.
moderatebeginner
HUBMaster reference for all Noritz tankless water heater error codes across the NR and NRCP condensing series.
lowbeginner
IGN-FAILUREThe Noritz water heater fails to ignite when hot water is demanded but the controller display does not show a numeric error code. This is a symptom guide for diagnosing ignition failure without a code.
highintermediate
NO-HOT-WATERError 11, 12, 90 Diagnosis
mediumintermediate
PRIORITY-LIGHTThe Priority indicator light on the Noritz remote controller is flashing or illuminated unexpectedly. Depending on the model and installation, this can indicate the unit is designated as the priority unit in a multi-unit installation, a service reminder is due, or an active fault needs attention.
moderatebeginner
RESETStep-by-step guide for performing a soft reset and a hard reset on Noritz NR and NRCP series tankless water heaters to clear error codes and restore operation.
lowbeginner
TROUBLESHOOTINGCatch-all troubleshooting guide covering the most common Noritz tankless water heater problems including no hot water, error codes, temperature issues, ignition problems, and condensate faults.
moderatebeginner