APC UPS Error Codes - Quick Reference
APC UPS systems from Back-UPS RS/Pro, Smart-UPS, and Symmetra lines communicate faults via LED indicators, beep codes, LCD displays, and via APC PowerChute software or network management cards.
| Code / Fault | System | Meaning | Quick Fix |
|---|---|---|---|
| 4 beeps / On Battery | All | Utility power lost | Check power source |
| Continuous beep | All | Battery critically low | Connect load, charge battery |
| Battery Replace LED | Smart-UPS | Battery at end of life | Replace battery |
| Overload LED (red) | Back-UPS/Smart-UPS | Load exceeds UPS rating | Reduce load |
| F01 | Symmetra | Battery failure | Replace battery module |
| F02 | Symmetra | Intelligence module fault | Replace I/O module |
| F06 | Symmetra | Overload on output | Reduce connected load |
| Site Wiring Fault LED | Smart-UPS | Building wiring problem | Check building electrical |
| Replace Battery | Smart-UPS LCD | Battery test failed | Replace battery |
| Overcharge | Back-UPS | Battery overcharge condition | Check charger circuit |
Most Common Faults
Replace Battery
Battery Replace LED or LCD message on APC Smart-UPS indicates the internal battery self-test has failed. APC VRLA batteries typically last 3–5 years depending on temperature and discharge frequency. Hot environments dramatically shorten battery life - every 10°C above 25°C cuts battery life in half.
To replace: power down the UPS or use APC’s “Battery Replace” procedure to hot-swap without dropping load (on Smart-UPS with HotSwap). Match the battery part number exactly - mixing battery chemistry or capacity causes charging problems.
Overload
Red overload LED means connected load exceeds the UPS VA rating. Check the load with a watt meter. Common causes: added equipment, printer with large inrush, or a failed component drawing excessive current. Remove load until the overload clears, then add equipment incrementally.
Site Wiring Fault
APC Smart-UPS checks building wiring and reports site wiring fault when it detects a missing safety ground or neutral-ground voltage issues. This is a building wiring problem - contact a licensed electrician. Running a UPS with a wiring fault can damage equipment and is a safety hazard.
Symmetra F01 - Battery Failure
Symmetra battery modules include individual cell monitoring. F01 can indicate one or more dead cells in a battery frame. Replace the indicated battery module; Symmetra systems allow hot-swap of individual modules without dropping load.
Parts Often Needed
| Part | Notes |
|---|---|
| Replacement battery (RBC) | Amazon | Size per UPS model - match RBC number |
| Symmetra battery module | Amazon | Hot-swappable |
| Network management card (NMC) | Amazon | Replace on network fault |
| Back-UPS output fuse | Amazon | Replace on output overload damage |
| Smart-UPS internal fuse | Amazon | Replace on no-output fault |
When to Call a Pro
Symmetra PX and Galaxy-series UPS maintenance, including bypass switching and capacitor replacement, requires APC/Schneider-trained technicians. Do not attempt internal repairs on large UPS systems without proper training.