What is the F40 error on Felicity?

F40 on a Felicity unit means: Isolation resistance to ground of the PV string is too low.. 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 F40 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 F40 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.

Critical

F40

Q: What does F40 mean on IVEM 6048?

Fault: CAN data loss. Cause: Communication cable connection issue between paralleled inverters. Recommended fix: 1. Check if communication cables are connected well and restart the inverter. 2. if the problem remains, please contact your installer.

Q: What does F40 mean on IVEM8048-II?

Fault: CAN data loss. Cause: CAN communication data loss between parallel inverters. Recommended fix: 1. Check if communication cables are connected well and restart the inverter. 2. if the problem remains, please contact your installer.

Q: What does F40 mean on IVEM8048-LV?

CAN data loss. Cause: Communication failure between paralleled inverters. Recommended fix: 1. Check if communication cables are connected well and restart the inverter. 2. if the problem remains, please contact your installer.

Isolation resistance to ground of the PV string is too low.

7 Devices that report this code

What does the F40 error code mean?

F40 on a Felicity unit indicates: Isolation resistance to ground of the PV string is too low.. 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

F40 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

F40Isolation resistance to ground of the PV string is too low.Critical

Description

Isolation resistance to ground of the PV string is too low.

Cause

Isolation resistance to ground of the PV string is too low.

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

IVEM 6048Inverter↗ view on device

F40CAN data loss.Fault

Description

Fault: CAN data loss.

Cause

Communication cable connection issue between paralleled inverters.

Recommended fix

1. Check if communication cables are connected well and restart the inverter. 2. if the problem remains, please contact your installer.

Source:felicitysolar IVEM 6048 Solar Inverter User Guide.pdf · page 38

IVEM8048-IIInverter↗ view on device

F40CAN data loss.Fault

Description

Fault: CAN data loss.

Cause

CAN communication data loss between parallel inverters.

Recommended fix

1. Check if communication cables are connected well and restart the inverter. 2. if the problem remains, please contact your installer.

Source:IVEM8K-12K-II_compressed.pdf · page 44

IVEM8048-LVInverter↗ view on device

F40CAN data loss.Fault

Description

CAN data loss.

Cause

Communication failure between paralleled inverters.

Recommended fix

1. Check if communication cables are connected well and restart the inverter. 2. if the problem remains, please contact your installer.

Source:FelicitySolar IVEM8048-LV Single Phase Hybrid Inverter User Guide.pdf · page 39

T-REX-10KHP3G01Inverter↗ view on device

F40Isolation resistance to ground of the PV string is too low.Critical

Description

PV string isolation resistance to ground below permitted threshold.

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

F40Isolation resistance to ground of the PV string is too low.Critical

Description

Isolation resistance to ground of the PV string is too low.

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

F40Bus short circuit fault.Fault

Description

Bus short, shut down and restart.

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

Frequently asked about F40

What is the F40 error on Felicity?: F40 on a Felicity unit means: Isolation resistance to ground of the PV string is too low.. 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 F40 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 F40 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.