Noritz Error Code 73: Circuit board setting abnormality (Tankless)
Noritz error code 73 on a tankless water heater means: Circuit board setting abnormality. It is also called Noritz diagnostic code 73.
Homeowner? What Noritz code 73 means for you
Usually minor Your tankless water heater is reporting: Circuit board setting abnormality. This code is usually informational or minor. The safe checks below often clear it; call us if it keeps showing up.
Safe things you can check yourself
- Check that gas reaches the house: other gas appliances work, or the propane tank is not empty.
- Make sure the heater is plugged in and its breaker is on. In winter, keep the power on: it protects the unit from freezing.
- Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
- Check that the hot and cold water valves under the heater are fully open.
- If you have a remote controller, turn it off and on once. If the code comes back, call a technician.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does Noritz error code 73 mean?
DIP switches or connectors were changed while the unit had power. On premix units it also shows when a replacement board was installed but not programmed.
Applies to: All Noritz residential tankless (EZ, NRCR, NCC199CDV, NRC/NRCP)
Common causes of Noritz code 73
- DIP switches or connectors changed with power on
- Replacement circuit board not programmed (premix)
Noritz models that use code 73
EZ71DVEZ98DVEZ111DVN-0841MCN-0841MC-DVN-0842MCN-0842MC-DVNCC199CDVNRC111-DVNRC111-SVNRCR92DVNRCR111DV
Other Noritz Tankless codes
All Noritz Tankless Water Heater error codes →
Noritz code 73: homeowner questions
What does Noritz code 73 mean?
Circuit board setting abnormality. DIP switches or connectors were changed while the unit had power. On premix units it also shows when a replacement board was installed but not programmed.
Is it safe to keep using my tankless water heater with code 73?
Usually yes. Code 73 is normally minor, but if it keeps coming back have it checked.
Can I reset Noritz code 73 myself?
You can try one reset (power off for 30 seconds, then on). If Noritz code 73 comes back, the cause is still there and a licensed technician should check it.
Who can fix Noritz code 73 near me?
Aurora Star Tech Inc. repairs Noritz tankless water heaters in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.
Homeowner help: Tankless Water Heater No Hot Water: What to Check
Troubleshooting guides
- No hot water All brands · Tankless Water Heater
- Water temperature fluctuates All brands · Tankless Water Heater
- Cleaning ignition and flame rods - Noritz Noritz · Tankless Water Heater
- Cleaning the fan and burner - Noritz EZ/NRCR/CDV Noritz · Tankless Water Heater
- Descaling (flushing) the heat exchanger - Noritz Noritz · Tankless Water Heater
- Draining to prevent freezing - Noritz EZ/NRCR Noritz · Tankless Water Heater
- Field gas conversion NG to LP - Noritz NRCR/EZ Pro Noritz · Tankless Water Heater
- Heat exchanger replacement - Noritz NRC111 / NCC199 Noritz · Tankless Water Heater
- Heater does not fire when hot water is opened - Noritz tankless Noritz · Tankless Water Heater
- Recirculation not working or hot water slow - Noritz NRCR Noritz · Tankless Water Heater
- Water not hot enough or temperature fluctuates - Noritz tankless Noritz · Tankless Water Heater
Source: Noritz EZ/NRCR/CDV Level 2 Maintenance & Troubleshooting (Premix R2 V2), 73 & F76 error codes, p.15; Noritz Residential Level 2 Maintenance & Troubleshooting (NRC/NRCP and older, R2 V1), 73 & F76 error codes, p.9. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.