39Fault

Felicity inverter error 39 (F39)

Leakage current sensor failed

Also displayed as F39 on some models.

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

The exact meaning depends on your model:

T-REX-3KLP1G01

InverterFault

Also applies to:T-REX-3K6LP1G01T-REX-4KLP1G01T-REX-4K6LP1G01T-REX-5KLP1G01T-REX-6KLP1G01T-REX-10KHP3G01T-REX-10KLP3G01

What it means

Leakage current sensor failed

Cause: The leakage current sensor returned an out-of-range or implausible reading, so the inverter can no longer verify that its leakage protection is working.

How to fix it

Restart the unit, if the error persists, contact the repair center.

Source: T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf, p.38 · T-REX-10KHP3G01-Inverter-User-Guide.pdf, p.29 · T-REX-10KLP3G01-Inverter-User-Guide.pdf, p.28

T-REX-50KHP3G01

InverterFault

What it means

Bus soft start fault — Bus voltage fails to rise normally at startup, shutdown and restart.

Cause: The DC bus failed to rise to its working voltage during the startup soft-start ramp — an internal converter or pre-charge fault.

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: T-REX-50KHP3G01-user-manual-.pdf, p.47

Apollo-5KLP1G01-MX

Energy storage systemCritical

Also applies to:Apollo-5KLP1G01-M1Apollo-5KLP1G01-M2Apollo-4K6LP1G01-MXApollo-4K6LP1G01-M1Apollo-4K6LP1G01-M2

What it means

Leakage current sensor failed

Cause: Leakage current sensor failed.

How to fix it

Restart the unit, if the error persists, contact the repair center.

Source: Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf, p.43

Frequently asked questions

What does error 39 mean on a Felicity inverter?
It depends on the model — 5 devices use code 39. On the T-REX-3KLP1G01 it means: Leakage current sensor failed. The card for each model on this page gives its exact meaning and fix.
Is error 39 a fault or a warning?
39 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 39?
Restart the unit, if the error persists, contact the repair center. The exact steps for each affected model are listed on this page.

Related error codes

Other codes on the T-REX-3KLP1G01

All T-REX-3KLP1G01 codes All T-REX-10KHP3G01 codes All T-REX-10KLP3G01 codes

Other codes on the T-REX-50KHP3G01

All T-REX-50KHP3G01 codes

Other codes on the Apollo-5KLP1G01-MX

All Apollo-5KLP1G01-MX 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.