These Rinnai gas heaters are fitted with self diagnostics electronics. When a fault occurs, the heater will shut down and the fault with a pair of digits will be displayed on the display screen. Refer to the following table for probable cause and suggested remedy.
| Error Code | Probable Cause | Suggested Remedy |
| 00 | Mains power failure during operation | Press the ON/OFF button twice to reset heater. |
| 03 | Tilt switch activated | Ensure appliance is level & upright. Service required if repeated |
| 10 | Oxygen shortage | Clean filters. Ventilate room. Service required if repeated. |
| 11 | Ignition failure | Check gas supply is turned on, turn the heater OFF and then ON again. If the heater fails to ignite after 4 attempts a Service will be required. |
| 12 | Incomplete combustion | Check gas supply is turned on, turn the heater OFF and then ON again. If the heater fails to ignite after 4 attempts a Service will be required. |
| 13 | Combustion control faulty | Service required |
| 14 | Filter Blockage / Overheat | Clean filters. If error continues a service will be required. |
| 16 | Room overheat | Lower room temp to below 40°C. |
| 18 | Thermocouple output error | Lacking in gas supply or incorrect gas type or Service required. |
| 31 | Room temperature sensor faulty | Service required |
| 32 | Overheat temperature sensor faulty | Service required |
| 33 | Overheat temperature sensor faulty | Service required |
| 34 | Overheat temperature sensor faulty | Service required |
| 62 | Faulty fan motor | Service required |
| 70 | ON/OFF switch faulty | Service required |
| 71 | Solenoids faulty | Service required |
| 72 | Flame detection circuit fault | Service required |
| 73 | Communication error | Press the ON/OFF button twice to reset heater. Service required if repeated. |
| Problem | Probable Cause | Suggested Remedy |
| No ignition or difficult to ignite | Incorrect gas pressure / Faulty igniter / Faulty safety device / Insufficient ventilation | Service required |
| Burner goes out | Dirty thermocouple / Faulty safety device | Service required |
| Noisy ignition | Incorrect gas pressure | Service required |
| Burner does not glow properly | Incorrect gas pressure | Service required |
| Flame or sooting from burner | Incorrect gas pressure | Service required |
| Strange noises | Incorrect gas pressure | Service required |
| Problem | Probable Cause | Suggested Remedy |
| Heater won't ignite | Gas filter blockage / Air in Hose | Service Required |
| Takes too long to warm the room | Gas filter blockage / Faulty Fan | Service Required |
| Smell of gas | Gas escape | Turn off gas. Service Required |