All codes
| Code | Meaning |
|---|---|
| 02 | No burner operation during freeze protection |
| 03 | Power interruption during bath fill |
| 05 | Bypass flow control device |
| 07 | Circulation flow rate below 2.1 GPM |
| 10 | Air supply or exhaust blockage, or condensate trap full |
| 11 | No ignition |
| 12 | Flame failure |
| 14 | Thermal fuse or overheat sensor |
| 16 | High outgoing water temperature (over 203°F / 95°C) |
| 19 | Electrical grounding |
| 21 | Data transfer error |
| 25 | Condensate pump error or drain clogged |
| 30 | Flammable vapor sensor |
| 31 | Burner thermocouple |
| 32 | Outgoing water temperature thermistor fault |
| 33 | Heat exchanger thermistor |
| 38 | Exhaust gas temperature sensor |
| 41 | Freeze protection sensor |
| 51 | Inlet water temperature thermistor |
| 54 | High exhaust gas temperature |
| 57 | Burner overheat bi-metal switch |
| 58 | Secondary heat exchanger sensor |
| 61 | Combustion fan motor |
| 63 | Recirculation low flow |
| 65 | Water flow control device |
| 70 | PC board fault |
| 71 | Gas solenoid valve |
| 72 | Flame rod fault |
| 73 | Burner thermocouple fault |
| 79 | Water leakage detected |
| FE | Flammable vapors detected |
| FF | Maintenance has been performed |
| SS | Time for service |
| LC | Scale build-up in heat exchanger |
Code names are from Rinnai’s diagnostic code manual (document 100000652). Explanations are written by us. Not affiliated with Rinnai.
Before you reset
Most codes clear when you turn the heater off and on at the controller – but a code that keeps coming back is telling you something. Codes for overheating (14, 16, 57, 58) and flammable vapors (FE) mean stop and call a technician, not reset and carry on.