36Fault

Felicity inverter error 36 (F36)

Grid Under Frequency Alarm

Also displayed as F36 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:

IVGM5KL-P1G1

InverterFault

Also applies to:IVGM6KL-P1G1IVGM7K6L-P1G1IVGM8KL-P1G1

What it means

Grid Under Frequency Alarm — Grid frequency is too low, check if the grid frequency is within the normal range.

Cause: The grid frequency measured at the AC terminals is below the permitted operating window, so the inverter alarms and holds off grid-tied operation until the frequency recovers.

How to fix it

Check if the grid frequency is within the normal range.

Source: Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf, p.51

T-REX-3KLP1G01

InverterFault

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

What it means

Internal fan locking fault

Cause: Internal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.

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-50KHP3G01

InverterFault

What it means

Bus overvoltage fault — Bus voltage is too high, shutdown and restart.

Cause: The internal DC bus tripped the hardware overvoltage protection, which acts independently of the firmware — a fast bus-voltage spike beyond the protection ceiling.

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

Frequently asked questions

What does error 36 mean on a Felicity inverter?
It depends on the model — 3 devices use code 36. On the IVGM5KL-P1G1 it means: Grid Under Frequency Alarm. The card for each model on this page gives its exact meaning and fix.
Is error 36 a fault or a warning?
36 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 36?
Check if the grid frequency is within the normal range. The exact steps for each affected model are listed on this page.

Related error 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 T-REX-50KHP3G01

All T-REX-50KHP3G01 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.