Rinnai SENSEI RX error codes
The SENSEI RX is Rinnai's current residential condensing tankless line (RXP models add a built-in recirculation pump). It is the generation with the Smart-Sense gas valve, a lime-detecting thermistor on the hot water pipe, an LC scale lockout that stops the unit after repeated warnings, and A/B service buttons on the PC board. Several codes below — 18, 22, 34 and 66 — exist only on this generation, and code 34 means something completely different here than on Rinnai's older units.
| Code | Error | Verdict |
|---|---|---|
| 03 | Power interruption during bath fill | DIY fix |
| 10 | Air supply or exhaust blocked, or the condensate trap is full | Call a pro |
| 11 | No ignition | Call a pro |
| 12 | Flame failure | Call a pro |
| 14 | Overheat sensor or thermal fuse tripped | Call a pro |
| 15 | Venturi control fault | Call a pro |
| 16 | Outlet water temperature too high | Call a pro |
| 17 | Venturi blockage | Call a pro |
| 18 | Gas valve adjustment limit reached | Call a pro |
| 19 | Electrical grounding fault | Call a pro |
| 21 | Data transfer error | Call a pro |
| 22 | Gas valve adjustment fault | Call a pro |
| 25 | Condensate pump fault or blocked condensate drain | DIY fix |
| 32 | Outgoing water temperature thermistor fault | Part replacement |
| 33 | Heat exchanger thermistor fault | Part replacement |
| 34 | Lime detecting thermistor fault | Part replacement |
| 38 | Exhaust gas temperature sensor fault | Call a pro |
| 41 | Freeze protection sensor fault | Part replacement |
| 51 | Inlet water temperature thermistor fault | Part replacement |
| 52 | Gas valve fault | Call a pro |
| 54 | Exhaust gas temperature too high | Call a pro |
| 61 | Combustion fan motor fault | Call a pro |
| 63 | Recirculation low flow | DIY fix |
| 65 | Water flow control valve fault | Part replacement |
| 66 | Bypass flow servo fault | Part replacement |
| 70 | PC board fault | Call a pro |
| 71 | Gas solenoid valve fault | Call a pro |
| 72 | Flame rod fault | Call a pro |
| FF | Maintenance performed marker | DIY fix |
| LC | Scale build-up lockout | DIY fix |
| SS | Service soon reminder | DIY fix |
Advertisement
Every entry above is transcribed from the manufacturer's diagnostic documentation for this exact series, with the source cited on each code page.