E21Fault

Felicity inverter error E21

GFCI Dev. Fault

Fault — the inverter cuts its output and the red LED stays solid until the fault is cleared.

E-CHO-SI3KS2

InverterFault

Also applies to:E-CHO-SI5KS2E-CHO-SI8KS2

What it means

GFCI Dev. Fault — GFCI device self-test/detection fault.

Cause: The GFCI (leakage-current) monitoring device failed its self-test. The sensor itself is faulty, and the inverter refuses to operate without working ground-fault protection.

How to fix it

  1. Power down the inverter, wait 5 minutes for capacitors to discharge, then restart.
  2. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line.

Source: E-CHO-SI3KS2-Operation-Manual.pdf, p.16 · E-CHO-SI5KS2-Operation-Manual.pdf · E-CHO-SI8KS2-Operation-Manual.pdf

Frequently asked questions

What does error E21 mean on a Felicity inverter?
E21 means: GFCI Dev. Fault. The GFCI (leakage-current) monitoring device failed its self-test. The sensor itself is faulty, and the inverter refuses to operate without working ground-fault protection.
Is error E21 a fault or a warning?
E21 is a fault code: the inverter cuts its output and the red LED stays solid until it is cleared.
How do I clear or fix error E21?
Power down the inverter, wait 5 minutes for capacitors to discharge, then restart. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line.

Related error codes

Other codes on the E-CHO-SI3KS2

All E-CHO-SI3KS2 codes All E-CHO-SI5KS2 codes All E-CHO-SI8KS2 codes

Prefer the full written guide? Read the complete Felicity inverter error-code guide

Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.