44Fault

Felicity inverter error 44 (F44)

AC input voltage and frequency are detected different

Also displayed as F44 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:

IVPS3524P1G1-LV

InverterFault

Also applies to:IVPS5048P1G1-LVIVPS7548P2G1IVPS10048P2G1IVPS3.5~10kVA-USIVPS3-5-10KVA

What it means

AC input voltage and frequency are detected different — The inverters in the parallel system detect different AC input voltage or frequency.

Cause: The utility wiring differs between inverters, or the units do not receive utility power at the same time.

How to fix it

  1. Check the utility wiring connection and restart the inverter.
  2. Make sure the utility starts up at the same time; if there are breakers installed between the utility and the inverters, make sure all breakers can be turned on at the AC input at the same time.
  3. If the problem remains, contact your installer.

Source: IVPS3524P1G1-LV IVPS5048P1G1-LV IVPS7548P2G1 IVPS10048P2G1 User Guide - EN.pdf, p.25

IVGM5KL-P1G1

InverterFault

Also applies to:IVGM6KL-P1G1IVGM7K6L-P1G1IVGM8KL-P1G1

What it means

BUS voltage unbalance fault — Entering LVRT at grid connection, the inverter absorbs reactive power from the grid.

Cause: When raised as a fault, the positive and negative halves of the internal DC bus have drifted apart in voltage. The same code number is used in the alarm list for low-voltage ride-through, where the inverter absorbs reactive power during a grid dip.

How to fix it

  1. Restart the system 2~3 times
  2. If the fault still exists, please contact us for help.

Source: Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf, p.52 · Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf, p.54

T-REX-3KLP1G01

InverterFault

Also applies to:T-REX-3K6LP1G01T-REX-4KLP1G01T-REX-4K6LP1G01T-REX-5KLP1G01T-REX-6KLP1G01

What it means

Loss of parallel hosts

Cause: The unit lost contact with the parallel host (master) inverter — usually a fault on the parallel communication line or the host powering down.

How to fix it

Test the parallel communication line, restart still have problems please contact the after-sales service.

Source: T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf, p.39

IVEM 6048

InverterFault

Also applies to:IVEM6048

What it means

The firmware version of each inverter is not the same

Cause: CPU/firmware versions differ between paralleled inverters.

How to fix it

  1. Update all inverter firmware to the same version
  2. Check the version of each inverter via LCD setting and make sure the CPU versions are same. if not, please contact your installer to provide the firmware to update
  3. After updating, if the problem still remains, please contact your installer.

Source: felicitysolar IVEM 6048 Solar Inverter User Guide.pdf, p.38

IVEM8048-II

InverterFault

Also applies to:IVEM12048-IIIVEM 8K-12K Series II

What it means

The firmware version of each inverter is not the same

Cause: Firmware versions on parallel inverters do not match.

How to fix it

  1. Update all inverter firmware to the same version
  2. Check the version of each inverter via LCD setting and make sure the CPU versions are same. if not, please contact your installer to provide the firmware to update
  3. After updating, if the problem still remains, please contact your installer.

Source: IVEM8K-12K-II_compressed.pdf, p.45

IVEM8048-LV

InverterFault

Also applies to:IVEM8048

What it means

The firmware version of each inverter is not the same

Cause: Mismatched firmware versions across paralleled inverters.

How to fix it

  1. Update all inverter firmware to the same version
  2. Check the version of each inverter via LCD setting and make sure the CPU versions are same. if not, please contact your installer to provide the firmware to update
  3. After updating, if the problem still remains, please contact your installer.

Source: FelicitySolar IVEM8048-LV Single Phase Hybrid Inverter User Guide.pdf, p.39

T-REX-10KHP3G01

InverterFault

What it means

Host data loss

Cause: Communication cables not connected well.

How to fix it

  1. Check if communication cables are connected well and restart the inverter.
  2. If the problem remains, please contact your installer.

Source: T-REX-10KHP3G01-Inverter-User-Guide.pdf, p.29

T-REX-10KLP3G01

InverterFault

What it means

Host data loss

Cause: Communication cables not connected well.

How to fix it

  1. Check if communication cables are connected well and restart the inverter
  2. If the problem remains, please contact your installer.

Source: T-REX-10KLP3G01-Inverter-User-Guide.pdf, p.29

T-REX-50KHP3G01

InverterFault

What it means

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

Cause: The inverter stage failed to raise its output voltage to the working point during the startup soft-start ramp — an internal fault rather than a wiring issue.

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 systemFault

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

What it means

Loss of parallel hosts — Loss of parallel hosts in parallel system.

Cause: Loss of parallel hosts.

How to fix it

Test the parallel communication line, restart still have problems please contact the after-sales service.

Source: Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf, p.44

Frequently asked questions

What does error 44 mean on a Felicity inverter?
It depends on the model — 10 devices use code 44. On the IVPS3524P1G1-LV it means: AC input voltage and frequency are detected different. The card for each model on this page gives its exact meaning and fix.
Is error 44 a fault or a warning?
44 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 44?
Check the utility wiring connection and restart the inverter. Make sure the utility starts up at the same time; if there are breakers installed between the utility and the inverters, make sure all breakers can be turned on at the AC input at the same time. The exact steps for each affected model are listed on this page.

Related error codes

Other codes on the IVPS3524P1G1-LV

All IVPS3524P1G1-LV codes

Other codes on the IVGM5KL-P1G1

All IVGM5KL-P1G1 codes

Other codes on the T-REX-3KLP1G01

All T-REX-3KLP1G01 codes

Other codes on the IVEM 6048

All IVEM 6048 codes

Other codes on the IVEM8048-II

All IVEM8048-II codes

Other codes on the IVEM8048-LV

All IVEM8048-LV 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.