Critical

F33

Bus soft start failed.

7 Devices that report this code

What does the F33 error code mean?

F33 on a Felicity unit indicates: Bus soft start failed.. It is a critical-severity event that can appear on 7 different devices in the Felicity catalog. The same code may have slightly different recommended fixes depending on the device — the per-device sections below show the exact wording from each device's official manual.

This is a critical-severity code

Critical codes trip the unit offline immediately. They typically indicate hardware failure (short-circuit, IGBT, BMS) or an unsafe operating condition. Do not bypass the fault — note the code and contact authorized service.

What triggers this code

F33 is triggered when the unit's protection or monitoring logic detects the specific condition described above. The exact trigger depends on the device — see the per-device sections for the official manual entry for each.

Apollo-5KLP1G01-MXEnergy storage system↗ view on device
F33Bus soft start failed.Critical
Description

Bus soft start failed; internal components failed.

Cause

Internal components failed.

Recommended fix

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

Source:Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf · page 43
IVEM 6048Inverter↗ view on device
F33Over current happen at LLC circuit.Fault
Description

Fault: Over current happen at LLC circuit.

Cause

Overcurrent in LLC resonant circuit.

Recommended fix

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

Source:felicitysolar IVEM 6048 Solar Inverter User Guide.pdf · page 38
IVEM8048-IIInverter↗ view on device
F33Over current happen at LLC circuit.Fault
Description

Fault: Over current happen at LLC circuit.

Cause

Over current detected in the LLC circuit.

Recommended fix

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

Source:IVEM8K-12K-II_compressed.pdf · page 44
IVEM8048-LVInverter↗ view on device
F33Over current happen at LLC circuit.Fault
Description

Over current happen at LLC circuit.

Recommended fix

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

Source:FelicitySolar IVEM8048-LV Single Phase Hybrid Inverter User Guide.pdf · page 39
T-REX-10KHP3G01Inverter↗ view on device
F33Bus soft start failed.Fault
Description

DC bus soft start procedure failed.

Cause

Internal components failed.

Recommended fix

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

Source:T-REX-10KHP3G01-Inverter-User-Guide.pdf · page 29
T-REX-10KLP3G01Inverter↗ view on device
F33Bus soft start failed.Critical
Description

Bus soft start failed.

Cause

Internal components failed.

Recommended fix

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

Source:T-REX-10KLP3G01-Inverter-User-Guide.pdf · page 28
T-REX-50KHP3G01Inverter↗ view on device
F33Battery 2 SOC Low fault.Fault
Description

Battery 2 SOC is too low, the battery should be charged.

Source:T-REX-50KHP3G01-user-manual-.pdf · page 46

Frequently asked about F33

What is the F33 error on Felicity?
F33 on a Felicity unit means: Bus soft start failed.. It can appear on 7 different devices in the Felicity catalog. The cause and recommended fix are listed for each device on this page.
Can I clear the F33 code myself?
It depends on the severity. Warning-level codes can usually be cleared by following the recommended fix. Fault and critical codes often require checking the source condition first; if the code returns immediately after restart, escalate to authorized service.
Is the F33 fix the same on every device?
The cause is consistent — it's the same protection logic. The exact fix wording can differ per device because each official manual addresses model-specific context (input ranges, parallel-config notes, firmware revisions). Use the per-device section that matches your unit.
Where does this information come from?
Every entry is sourced directly from the official Felicity user manual for the affected device. The "Source" line at the bottom of each device's section shows the manual filename and page number.

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