HVACopediaBosch air handler error codes
7 codes with causes and test steps.
| Code | Meaning | Severity |
|---|---|---|
| 2 flashes | Indoor T2 sensor fault | Medium |
| 3 flashes | Refrigerant sensor fault | Medium |
| 4 flashes | Refrigerant sensor communication fault | Medium |
| 5 flashes | Indoor-to-outdoor communication fault | High |
| 8 flashes | Refrigerant sensor past service life | Low |
| Continuous flashing | R-454B refrigerant leak protection | Critical |
| LED off | Power supply failure | High |
Models covered
BIVA20-24BIVA20-36BIVA20-48BIVA20-60BVA-24WN1-M20BVA-36WN1-M20BVA-48WN1-M20BVA-60WN1-M20
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.