Fault

21

OP current sensor failed.

4 Devices that report this code

What does the 21 error code mean?

21 on a Felicity unit indicates: OP current sensor failed.. It is a fault-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 fault-severity code

Fault codes stop normal operation but the unit may attempt to recover. Common causes are out-of-range conditions (voltage, current, temperature) that require checking inputs and outputs before restart.

What triggers this code

21 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.

IVCM1012 PROInverter↗ view on device
21OP current sensor failed.Fault
Description

OP (output) current sensor failed.

Recommended fix

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

Source:ICM.pdf · page 13
IVGM5KL-P1G1Inverter↗ view on device
21BMS communication Alarm.Fault
Description

Abnormal communication between battery and inverter in non-SOC mode, check battery and inverter wiring.

Recommended fix

Check battery and inverter wiring.

Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf · page 51
LUX-S-1600LG01Battery↗ view on device
21PV Mos Short.Fault
Description

Fault event: PV input MOSFET short-circuit fault detected.

Recommended fix

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

Source:LUX-S-1600LG01.pdf · page 22
T-REX-3KLP1G01Inverter↗ view on device
21OP current sensor failed.Fault
Description

Output current sensor failed.

Recommended fix

Output current sensor failed.

Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf · page 38

Frequently asked about 21

What is the 21 error on Felicity?
21 on a Felicity unit means: OP current sensor failed.. 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 21 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 21 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.