INV over voltage fault
Also displayed as F54 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:
Also applies to:IVGM6KL-P1G1IVGM7K6L-P1G1IVGM8KL-P1G1
INV over voltage fault — Inverter over voltage fault.
Cause: The inverter measured its own AC output voltage above the permitted range — an internal regulation fault rather than a wiring issue.
Source: Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf, p.54
Also applies to:T-REX-3K6LP1G01T-REX-4KLP1G01T-REX-4K6LP1G01T-REX-5KLP1G01T-REX-6KLP1G01T-REX-10KHP3G01
Temperature sensor disconnected
Cause: An internal temperature sensor is no longer detected, so the inverter has lost a measurement it needs for thermal protection.
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.39 · T-REX-10KHP3G01-Inverter-User-Guide.pdf, p.29
Grid Underfrequency Fault — The grid frequency is too low, check whether the grid frequency is within the normal range.
Cause: The grid frequency is below the inverter's permitted operating window, so it disconnects until the frequency recovers.
Source: T-REX-50KHP3G01-user-manual-.pdf, p.47
Also applies to:Apollo-5KLP1G01-M1Apollo-5KLP1G01-M2Apollo-4K6LP1G01-MXApollo-4K6LP1G01-M1Apollo-4K6LP1G01-M2
Temperature sensor disconnected
Cause: Temperature sensor disconnected.
Restart the unit, if the error persists, contact the repair center.
Source: Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf, p.44
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.