What is the W09 error on Felicity?

W09 on a Felicity unit means: Overload.. 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 W09 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 W09 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.

Warning

W09

Overload.

4 Devices that report this code

What does the W09 error code mean?

W09 on a Felicity unit indicates: Overload.. It is a warning-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 warning-level code

Warning codes do not stop the unit. They flag a condition that should be addressed before it escalates — usually a near-threshold reading or a configuration check.

What triggers this code

W09 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

W09Overload.Warning

Description

Overload warning. Audible alarm: beep twice every second.

Recommended fix

Reduce the loads.

Source:Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf · page 42

T-REX-10KHP3G01Inverter↗ view on device

W09Overload.Warning

Description

Overload warning. Audible alarm: beep twice every second.

Recommended fix

Reduce the loads.

Source:T-REX-10KHP3G01-Inverter-User-Guide.pdf · page 27

T-REX-10KLP3G01Inverter↗ view on device

W09Overload.Warning

Description

Overload warning. Audible alarm: beep twice every second.

Recommended fix

Reduce the loads.

Source:T-REX-10KLP3G01-Inverter-User-Guide.pdf · page 27

T-REX-50KHP3G01Inverter↗ view on device

W09Under-frequency derating alarm.Fault

Description

The frequency is too low, the inverter reduce the power.

Source:T-REX-50KHP3G01-user-manual-.pdf · page 44

Frequently asked about W09

What is the W09 error on Felicity?: W09 on a Felicity unit means: Overload.. 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 W09 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 W09 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.