Noritz Error Code 73: Circuit Board Setting Error
Warning: Your Noritz water heater is experiencing a circuit board setting error, which has caused it to shut down. It's safe to troubleshoot, but don't attempt any repairs yourself.
How to Fix Noritz Code 73
- Step 1: Turn off the power to your Noritz water heater at the circuit breaker.
- Step 2: Wait for 30 seconds, then turn the power back on. The unit should reset and try to boot up.
- Step 3: If the error persists, or you hear unusual noises, call a professional HVAC technician.
How to Reset Noritz Code 73
- Turn off the unit using the power button on the front panel.
- Turn off the gas supply valve.
- Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
- Restore power at the breaker, then open the gas valve.
- Turn the unit back on. If the error returns, the underlying issue needs repair.
What does 73 mean?
The Noritz 73 error code indicates a problem with the circuit board's settings. This could be due to a software glitch, a power surge, or a faulty component. The unit has entered a safe mode and shut down to prevent further damage. Before you call a professional, let's try a simple reset.
Affected Models
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Circuit Board | NR-CB-001 | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| 10 | Flame Failure | Warning |
| 11 | Ignition Failure | Warning |
| 14 | Thermal Fuse Failure | Warning |
| 29 | Condensate Drain Issue | Warning |
| 31 | Inlet Thermistor Failure | Warning |
| 32 | Outlet Thermistor Failure | Warning |
| 33 | Heat Exchanger Thermistor Failure | Warning |
| 43 | Water Level/Neutralizer Issue | Warning |
| 45 | Water Leak Detected | Warning |
| 51 | Fan Motor Failure | Warning |