Noritz Error Code 33: Heat Exchanger Thermistor Failure
Warning: Your Noritz water heater is locked out due to a heat exchanger thermistor failure. It's safe to operate, but needs professional repair.
How to Fix Noritz Code 33
- Check if the water heater is still under warranty. If so, contact Noritz for repair or replacement.
- Turn off the power to the water heater at the circuit breaker for safety.
- Contact a licensed HVAC technician for repair. Do not attempt to fix this issue yourself.
How to Reset Noritz Code 33
- 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 33 mean?
The error code 33 on your Noritz water heater indicates a failure in the heat exchanger thermistor. This component measures the temperature of the heat exchanger and sends this information to the control board. When it fails, the system locks out to prevent overheating and potential damage. This is a common issue in Noritz water heaters and is typically caused by normal wear and tear or exposure to hard water.
Affected Models
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Heat Exchanger Thermistor | NOR-30066 | — |
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 |
| 43 | Water Level/Neutralizer Issue | Warning |
| 45 | Water Leak Detected | Warning |
| 51 | Fan Motor Failure | Warning |
| 61 | Fan Motor Failure | Warning |