APC Smart-UPS Error Code F21

APC UPS Major Fault

Model: Smart-UPS | Code: F21

Applicable Systems
Symmetra LX

Symptoms

The digital-to-analog converter has a fault. Control outputs may be incorrect.

Possible Causes

  • DAC chip hardware failure
  • DAC reference voltage out of specification

Troubleshooting Steps

  1. Step 1: Check the UPS fault log for the specific dac fault sub-code
    Detailed fault information is obtained
  2. Step 2: Contact APC support with the fault code for diagnosis
    Support confirms the faulty component

How to Reset

To reset: Power-cycle the UPS. If the error persists, contact APC support for repair.

Related APC Fault Codes

Source: APC Smart-UPS User Manual, Schneider Electric/APC

Category: UPS