Noritz · Water heater
Code 45 Internal water leak detected
What this code means
A leak sensor behind the circuit board (on NRCP/CB models) has detected accumulated water.
Most likely causes
- Internal fitting or seal leak
- Condensate overflow reaching the sensor well
What to try first
Shut off the water and power to the unit and don't attempt to keep resetting it.
Safety first: stop using the appliance and shut off its gas or power until it has been inspected — this fault category is associated with fire or gas risk.
FAQ
What does Noritz error code Code 45 mean?
Internal water leak detected. A leak sensor behind the circuit board (on NRCP/CB models) has detected accumulated water.
Can I fix Noritz code Code 45 myself?
No — stop using the appliance and shut off its gas or power until it has been inspected. This fault category is associated with fire or gas risk.
What causes Noritz code Code 45?
The most common causes are: internal fitting or seal leak; condensate overflow reaching the sensor well.
Other Noritz water heater codes
All Noritz water heater error codes →
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This information may contain errors or not apply to your exact model — always double-check it against your appliance's own manual before acting. If there's any chance of a gas, fire, electrical, carbon monoxide, or other safety hazard, stop and call a licensed professional or the appropriate agency (e.g. your gas utility) instead of relying on this page alone.