Noritz Error Codes

Find troubleshooting guides for all Noritz error codes.

14 error codes across 1 appliance types

Waterheater

Code	Meaning	Severity
11	The unit attempted ignition three times and could not establish a flame. No flame signal was detected by the flame rod during any attempt. high	high
12	The 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. high	high
14	The thermal fuse sits in the heat exchanger circuit and it's literally just a wire rated for one specific temperature. When the exchanger gets hot enough to hit that threshold, the wire inside melts apart and breaks the circuit permanently. The unit won't fire up again until that fuse is physically swapped out. critical	critical
16	The gas pressure sensor at the unit's inlet detected that incoming supply pressure dropped below 3.5 or climbed above 10.5 inches water column during operation, or the combustion monitoring system sensed abnormal flame characteristics consistent with an improper gas-to-air ratio caused by pressure issues. high	high
20	The combustion fan (blower motor) has failed, stalled, or can't reach the required operating speed. Without that fan moving air through the chamber, the unit won't light, period. It handles both pulling in fresh combustion air and pushing exhaust gases out. high	high
29	The heat exchanger temperature sensor detected a temperature exceeding the safe operating threshold (160 to 180 degrees F). The unit shut down to prevent damage. high	high
90	The combustion sensor detected abnormal combustion. Most commonly caused by exhaust gases recirculating back into the air intake, producing oxygen-depleted combustion air. high	high
CONDENSATE-DRAIN	Condensing 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. moderate	moderate
HUB	Master reference for all Noritz tankless water heater error codes across the NR and NRCP condensing series. low	low
IGN-FAILURE	The 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. high	high
NO-HOT-WATER	The water heater attempted to start a burner cycle but failed. Error 11 means the igniter fired but no flame was detected within the retry window. Error 12 means ignition failed completely. The control board killed gas flow as a safety measure to prevent unburned gas from building up. moderate	moderate
PRIORITY-LIGHT	The Priority indicator on your Noritz remote is flashing or lit when it shouldn't be. Could mean the unit's counting this remote as the designated controller in a multi-unit setup, a service interval just triggered, or there's an active fault trying to get your attention through that green light. moderate	moderate
RESET	When Noritz units detect a fault, they lock the gas valve and store an error code in volatile memory. A soft reset clears that memory by cycling the controller, while a hard reset at the breaker drains the board's capacitors completely. Either way, the unit runs a full self-diagnostic before allowing the gas valve to open again. low	low
TROUBLESHOOTING	When a Noritz tankless heater has a problem, it either throws an error code or shuts down silently. The unit constantly monitors flow rate, flame signal, exhaust temps, and water pressure. When any of those readings go out of range, it shuts itself down to avoid damage. moderate	moderate