Noritz · Water heater
Code 16 Abnormally high outlet temperature
What this code means
Water is coming out hotter than the temperature it was set to.
Most likely causes
- Scale buildup inside the heat exchanger
- Stuck internal mixing/bypass valve
- Low water flow concentrating heat
What to try first
This is a scale-and-internal-component issue best handled with a professional descaling service.
Safety note: if this code returns after one clean reset, stop resetting it — repeated lockouts usually mean a real fault that needs a licensed technician. Never bypass a safety switch.
FAQ
What does Noritz error code Code 16 mean?
Abnormally high outlet temperature. Water is coming out hotter than the temperature it was set to.
Can I fix Noritz code Code 16 myself?
Usually not. This is a scale-and-internal-component issue best handled with a professional descaling service. If the code returns after one reset, it needs a licensed technician.
What causes Noritz code Code 16?
The most common causes are: scale buildup inside the heat exchanger; stuck internal mixing/bypass valve; low water flow concentrating heat.
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.