Noritz Error Code 66: Bypass Flow Control Valve Failure
Warning: Your Noritz water heater is locked out due to a potential safety issue. Do not attempt to fix it yourself.
How to Fix Noritz Code 66
- Step 1: Turn off the power to your water heater at the circuit breaker.
- Step 2: Contact a licensed HVAC technician to diagnose and repair the issue.
- Step 3: Do not attempt to open the water heater or tamper with any internal components.
How to Reset Noritz Code 66
- 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 66 mean?
Error code 66 on your Noritz water heater indicates a failure in the bypass flow control valve. This valve is responsible for regulating water flow through the heat exchanger. If it fails, it can cause the water heater to overheat, posing a safety risk. The water heater will shut down to prevent any potential hazards.
Affected Models
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Bypass Flow Control Valve | NOR-123456 | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| 10 | Flame Failure | Warning |
| 11 | Ignition Failure | Warning |
| 12 | Flame Loss | Warning |
| 14 | Thermal Fuse Failure | Warning |
| 16 | Over-Temperature | 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 |