Critical

F51

DSP1 communication failure.

4 Devices that report this code

What does the F51 error code mean?

F51 on a Felicity unit indicates: DSP1 communication failure.. It is a critical-severity event that can appear on 4 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

F51 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
F51DSP1 communication failure.Critical
Description

DSP1 communication failure.

Cause

DSP1 communication failure.

Recommended fix

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

Source:Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf · page 44
T-REX-10KHP3G01Inverter↗ view on device
F51DSP1 communication failure.Fault
Description

DSP1 communication failure.

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
F51DSP1 communication failure.Fault
Description

DSP1 communication failure.

Recommended fix

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

Source:T-REX-10KLP3G01-Inverter-User-Guide.pdf · page 29
T-REX-50KHP3G01Inverter↗ view on device
F51Grid Overvoltage Fault.Fault
Description

The grid voltage is too high, check whether the grid voltage is within the normal range.

Source:T-REX-50KHP3G01-user-manual-.pdf · page 47

Frequently asked about F51

What is the F51 error on Felicity?
F51 on a Felicity unit means: DSP1 communication failure.. It can appear on 4 different devices in the Felicity catalog. The cause and recommended fix are listed for each device on this page.
Can I clear the F51 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 F51 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.