| 03 | Takagi Water Heater Error Code 03: How to Fix It | medium | Medium |
| 04 | Takagi Water Heater Error Code 04: How to Fix It | medium | Hard |
| 05 | Takagi Water Heater Error Code 05: How to Fix It | medium | Medium |
| 10 | Takagi Water Heater Error Code 10: How to Fix It | high | Medium |
| 11 | Takagi Water Heater Error Code 11: How to Fix It | high | Medium |
| 12 | Takagi Water Heater Error Code 12: How to Fix It | high | Hard |
| 14 | Takagi Water Heater Error Code 14: How to Fix It | high | Hard |
| 16 | Takagi Water Heater Error Code 16: How to Fix It | medium | Medium |
| 20 | Takagi Water Heater Error Code 20: How to Fix It | high | Medium |
| 24 | Takagi Water Heater Error Code 24: How to Fix It | medium | Medium |
| 29 | Takagi Water Heater Error Code 29: How to Fix It | high | Hard |
| 31 | Takagi Water Heater Error Code 31: How to Fix It | medium | Medium |
| 32 | Takagi Water Heater Error Code 32: How to Fix It | medium | Medium |
| 34 | Takagi Water Heater Error Code 34: How to Fix It | medium | Medium |
| 60 | Takagi Water Heater Error Code 60: How to Fix It | medium | Medium |
| 65 | Takagi Water Heater Error Code 65: How to Fix It | medium | Medium |
| 72 | Takagi Water Heater Error Code 72: How to Fix It | medium | Medium |
| 76 | Takagi Water Heater Error Code 76: How to Fix It | medium | Medium |
| 99 | Takagi Water Heater Error Code 99: How to Fix It | medium | Medium |