Rheem · Water heater
Code 16 Outlet water temperature sensor fault
What this code means
The sensor reading the temperature of water leaving the tankless unit isn't reporting correctly.
Most likely causes
- Failed or scaled thermistor
- Loose wiring connection
What to try first
Needs the unit opened for sensor testing.
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 Rheem error code Code 16 mean?
Outlet water temperature sensor fault. The sensor reading the temperature of water leaving the tankless unit isn't reporting correctly.
Can I fix Rheem code Code 16 myself?
Usually not. Needs the unit opened for sensor testing. If the code returns after one reset, it needs a licensed technician.
What causes Rheem code Code 16?
The most common causes are: failed or scaled thermistor; loose wiring connection.
Other Rheem water heater codes
All Rheem water heater error codes →
Other water heater brands: Ruud · Rinnai · Navien · Noritz · Takagi · A.O. Smith · Bradford White · State / American · Generic electric · Generic tankless
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.