Rinnai SENSEI error codes
The SENSEI is the condensing generation Rinnai sold before the SENSEI RX, and it is on a very large number of US walls — RU models, RUR and RSC with a recirculation pump, indoor (i) and outdoor (e). Its code table is not the RX table. It has code 05 for the bypass flow control device, where the RX moved that fault to code 66; it has no LC scale lockout at all, so scale surfaces only as the SS service reminder; and codes 18, 22 and 34 do not exist on it. Gas type is set by a physical orifice in the gas valve (red for propane, blue for natural gas) rather than by a software parameter, and the reset sequences on the PC board are different too.
Not your models? Check the model-number decoder before you read the table below — the code numbers repeat across series and the meanings do not.
| Code | Error | Verdict |
|---|---|---|
| 03 | Power interruption during bath fill | DIY fix |
| 05 | Bypass flow control device fault | Part replacement |
| 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 |
| 19 | Electrical grounding fault | Call a pro |
| 21 | Data transfer error | 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 |
| 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 |
| 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 |
| SS | Service soon reminder | DIY fix |
Every entry above is transcribed from the manufacturer's diagnostic documentation for this exact series, with the source cited on each code page.
Other Rinnai series
Different series, different code table — if your unit isn't a SENSEI, check yours: