Takagi Condensing error codes
Takagi publishes a separate troubleshooting guide for its condensing on-demand models, and the codes below are that guide's table. Two of them are worth knowing before you need them: 101 is a warning for abnormal combustion and 991 is the error it becomes, and 711 covers a hi-limit switch that has a physical reset button — Takagi's own first step on several other codes is to check whether that button has tripped. The non-condensing range has its own guide and its own table.
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 |
|---|---|---|
| 031 | Incorrect DIP switch settings | Call a pro |
| 101 | Abnormal combustion (warning) | Call a pro |
| 111 | Ignition failure | Call a pro |
| 121 | Flame loss | Call a pro |
| 311 | Output thermistor fault | Part replacement |
| 321 | Inlet thermistor fault | Part replacement |
| 331 | Mixing thermistor fault | Part replacement |
| 341 | Exhaust thermistor fault | Call a pro |
| 391 | Air-fuel ratio rod failure | Call a pro |
| 441 | Flow sensor fault | Part replacement |
| 510 | Main and solenoid gas valve fault | Call a pro |
| 551 | Solenoid valve fault | Call a pro |
| 611 | Fan motor fault | Call a pro |
| 621 | Exhaust fan motor fault (indoor models) | Call a pro |
| 631 | External pump fault | Part replacement |
| 651 | Flow adjustment valve fault | Part replacement |
| 661 | Water bypass valve fault | Part replacement |
| 701 | Proportional valve or computer board fault | Call a pro |
| 711 | Hi-limit switch or overheat cutoff fuse | Call a pro |
| 721 | False flame detection | Call a pro |
| 741 | Remote controller communication failure | Part replacement |
| 761 | Easy-Link communication failure | Call a pro |
| 941 | Abnormal exhaust temperature | Call a pro |
| 991 | Abnormal combustion | Call a pro |
Every entry above is transcribed from the manufacturer's diagnostic documentation for this exact series, with the source cited on each code page.
Other Takagi series
Different series, different code table — if your unit isn't a Condensing, check yours: