F21

Relay(s) Welded

Schneider Electric · XW Pro NA Operation Guide

What does F21 mean?

This Manual Fault indicates that an unidentified transfer relay is faulty, or an external AC source was incorrectly wired directly to the AC output. This can lead to improper power transfer and potential damage to the inverter.

Complete Troubleshooting Guide

  1. 1

    Disconnect the inverter’s output wiring.

  2. 2

    If error continues, have unit serviced.

Source: Schneider Electric Manual