Your safety is our #1 priority. Contact Happy Plumbing for further troubleshooting. Our technicians can help you diagnose the problem.
Please note: Your water heater model may use different codes or may provide error codes that are not given here. Therefore you’ll want to consult the manual for your specific heater.
Error Code
Meaning
| Noritz Code 05 | Service Warning (Turns on automatically when service is due) Call Happy Plumbing service technician for regular service. |
| Noritz Code 10 | The problem in gas combustion causes the power level to drop, while the combustion continues even after shutdown. Check for foreign materials found on the burner which is burning after gas combustion stops. (Clean the burner if dirty) Check for blocked exhaust flue. To reset the error code 10, the power must be disconnected If there is a recirculation loop use an aquastat to keep 10-degree differential. Turn the unit off, then back on. |
| Noritz Code 11 | Ignition Failure. Check that the gas valve opens. Press the power button to turn the unit off, open a hot water faucet, and turn the unit back on. If the error code no longer flashes the problem is solved. Check for blocked combustion air supply. Check for debris on the gas burner or gas supply orifice. Check for proper gas type (LP vs Natural gas), pressure, free flow through gas piping and valves, clean flame rod (ignition rod), assure no blockage in vent or vent connector, and clean ignition plug. |
| Noritz Code 12 | Burner flame loss during operation, or Bad flame detection rod. Weak flame. Check for proper gas pressure, free flow, and no blockage in the vent. Check for adequate combustion air. Clean ignition plug & flame sensor rod. Also, see Noritz error code 11. |
| Noritz Code 14 | Thermal fuse failure. Replace the thermal fuse. The thermal fuse is a white cord that wraps around the heat exchanger. Failure cause: scaled or dirty heat exchanger, Check for obstructed combustion airflow, and clean proper burner operation. Check water quality for hardness or sediment that can clog the heat exchanger. Flush scaled heat exchanger. Use a scale remover if needed. |
| Noritz Code 16 | Extremely high water temperature. Watch out: excessive Noritz hot water temperature is a dangerous scalding hazard. Check for sediment or scale clogging and clean or de-scale the unit using a cleaner such as vinegar or a de-scaler. Check manifold pressure adjustment. |
| Noritz Code 20 | High-limit switch activated. Check or replace the high-limit switch. Check for scale and de-scale the heater. |
| Noritz Code 21 | Pressure switch abnormality. Check/replace the pressure switch. Check fan motor operation. Check for blocked exhaust flue. |
| Noritz Code 29 | High water level in neutralizer; neutralizer clogged. Condensate drainage problem. Check for clogged condensate drain; check for damp or wet or damaged water level sensor. Check for frozen neutralizer due to condensate clogging. |
| Noritz Code 31 | Inlet thermistor failure. Replace the inlet thermistor. |
| Noritz Code 32 | Outlet thermistor failure. Replace the outlet thermistor. |
| Noritz Code 33 | Heat exchanger thermistor failure. Replace the heat exchanger thermistor. |
| Noritz Code 410 | Multi-system flow imbalance error. Check the blocked heater flow Check heater filter Check the flow sensor for damage or debris |
| Noritz Code 45 | Water leak. Close the water supply valve. Look for water leaks. If no leak is seen, unplug the heater for 30 seconds or more, then re-connect. If the error code clears continue use; else call Happy Plumbing for service. |
| Noritz Code 51 | Noritz Code 51: Gas Manifold Solenoid Failure A reader opined that for some models this code means Noritz manifold replacement is needed. See Error Code 59 below. |
| Noritz Code 56 | CCP Valve abnormality Check for blocked heater flow/obstructions Check CCP valve via the system controller & replace uncertain CCP valve |
| Noritz Code 57 | Not listed, check that you are reading the code correctly, then contact the company directly. |
| Noritz Code 59 | Low input BTU, insufficient gas supply, combustion problems such as obstructed exhaust flow. Check for blocked exhaust flue. Check for adequate combustion air; check for blocked exhaust venting; clean fan motor & burner chamber. Check for a stuck exhaust damper or too-long or too many elbows in exhaust vent. Check that the heater is properly set for the elevation where installed. Occurs if natural gas pressure is below 5″ WC or propane below 8″ WC. |
| Noritz Code 61 | Fan motor failure. Check the voltage of the fan motor. Replace the faulty fan motor or faulty circuit board (that controls the fan). |
| Noritz Code 63 | Recirculation Abnormality – Condensing Tankless Gas Water Heater NRCR111DV & NRCR92DV Check the return line filter. Check the crossover valve’s filter. |
| Noritz Code 65 | Main flow control valve abnormality Check for blockage of the main servo Check the operation of the main servo The main servo may need to be replaced |
| Noritz Code 66 | Bypass flow control valve failure. Check for blockage of the bypass servo valve or replace the valve. |
| Nortiz Code 67 | AGM (Air-Gas Mixer) abnormality. Turn power off, wait 30 seconds, turn power on. If code clears, continue use. If code reappears, replace the AGM |
| Noritz Code 70 | Circuit board fault. Replace the circuit board. |
| Noritz Code 71 | Gas valve drive circuit abnormality. The water heater is connected to battery backup, solar power, or generator, and the voltage supply is not stable. Check the voltage delivered from the circuit board. Check the unit’s electrical ground continuity. In areas of unstable power, install a power surge protector. |
| Noritz Code 72 | Flame rod flame detection error: flame detected without proper ignition sequence. Check for proper electrical ground. Check for the damaged circuit board. Check for damaged flame detection circuit/wires |
| Noritz Code 73 | Circuit board setting error. Reset the unit by disconnecting the power. Review & correct circuit board programming/switches. Common cause: connection changed with power on. Check for circuit board damage If failure persists replace the circuit board. |
| Noritz Code F76 | Multi-system communication error. Breakdown in communication between two tankless water heaters using the Quick Connect Cord. Disconnect the power to reset the unit. Check cord connections. Make sure that only one remote control is hooked up when two units are connected. |
| Noritz Code 760 | Remote controller problem. Check for loose wire connections. Reset the unit. Unplug from power, wait 30 seconds, and re-connect. Check that only 1 remote controller is connected to the heater. |
| Noritz Code 90 / 99 | Combustion gas alert. Check for proper gas flame color (light blue, yellow tips). Check for the blocked flue, and dirt on the gas burner. Have a professional check the gas supply pressure. |
| Noritz Code 90 | Combustion gas problem. Check for proper combustion air, check flame color – as per code 90/99 above. To reset the Noritz error code: unplug the unit for 30 seconds, then re-connect. |
| Noritz Code 92, 93 | Neutralizer near the end of life Replace the neutralizer immediately |
| Noritz Code F90 | Combustion gas alert. (Improper air-fuel mix) Check for blocked exhaust flue. Check for debris in the fan motor. Have a professional check the gas supply pressure. Check vent length, bends, elbows, draft, dip switches. |
| Noritz Code 903 | Combustion abnormality Check combustion airflowCheck combustion flame, gas supply Check the exhaust vent for blockage |
| Noritz Code 941, 942 | Excessive exhaust temperature Check combustion air supply for blockage Check the exhaust vent for blockage Call for service/repair. |
| Noritz Code F99 | Check for blocked exhaust flue. |
| Noritz Code 92 / 93 Noritz Code F92 Noritz Code F93 | Neutralizer life cycle alert. Replace the neutralizer & reset the burner timer. |
| Noritz Error Code C or CF Noritz Code CF1 CF2 CF3 or CF4 Noritz Code CFH | Scale blockage of the heat exchanger. The heater will be locked off. Flush & clean the heat exchanger. You may need to hire a trained service technician to use a scale-removing cleaner or chemical. Heat exchanger replacement is needed in severe cases. |
| Noritz Code H nn H followed by 2 numeric digits | Scale blocked heat exchanger, detected after re-connecting electrical power |