This is the complete fault table for the Felicity T-REX-3KLP1G01 Inverter family — 47 codes shared by 6 model numbers, transcribed from the official manual. On Felicity units, a fault code means the unit has cut its output and the red LED stays solid; a warning flashes the red LED while the unit keeps running.
Last checked against the official manuals on July 10, 2026.
CauseThe PV string voltage exceeds the inverter's maximum DC input rating — typically a string configured with too many modules in series.
Recommended fixReduce the number of PV modules in series.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseCurrent from the PV array exceeded the input stage's protection limit, so the inverter shut the PV input down.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseA short circuit was detected at the PV input — the array wiring presents a near-zero-resistance path, so the input stage shut down.
Recommended fixCheck if wiring is connect well.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe PV current sensor returned an out-of-range or implausible reading, so the control board can no longer trust its PV current measurement.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
The battery voltage is too low, it should be charging.
CauseWhen shown as a fault, the battery voltage at the terminals is above the inverter's permitted range — usually a battery bank whose specification or series count does not match the unit. The same number appears in the warning list for low battery voltage, meaning the pack needs charging.
Recommended fixCheck if spec and quantity of batteries are meet requirements.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe connected load exceeds the inverter's continuous output rating; the buzzer beeps twice every second and protection will cut the output if the load is not reduced.
Recommended fixPower down the inverter, wait 5 minutes for capacitors to discharge, then restart. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe LLC resonant converter (the isolated DC link inside the unit) is operating outside its normal envelope — an internal converter fault rather than a wiring issue.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe buck-boost converter stage drew current above its protection limit.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe buck-boost converter stage has drifted out of balance — its internal operating points are no longer matched, which is an internal converter fault rather than a wiring issue.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe buck-boost current sensor returned an out-of-range or implausible reading, so the control board can no longer trust that stage's current measurement.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe second buck-boost current sensor returned an out-of-range or implausible reading, so the control board can no longer trust that channel's current measurement.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe output ran in overload longer than the permitted grace period, so protection tripped rather than allow continued operation above rating.
Recommended fixReduce the connected load by switching off some equipment.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseA short circuit was detected on the inverter output: current spiked while voltage collapsed, pointing to a wiring fault or an abnormal (shorted) load.
Recommended fixCheck if wiring is connected well and remove abnormal load.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe AC input and output wiring are swapped — the inverter detects source voltage on its output terminals, so it refuses to run until the connections are corrected.
Recommended fixConfirm that the input and output wiring is correct.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
Output current sensor failed.
CauseThe output current sensor returned an out-of-range or implausible reading, so the control board can no longer trust its output-current measurement.
Recommended fixOutput current sensor failed.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe AC output voltage sagged below the permitted range — usually the connected load exceeds what the inverter can hold voltage into.
Recommended fixReduce the connected load.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe inverter measured its own AC output voltage above the permitted range — an internal regulation fault rather than a wiring issue.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe control software measured a current or surge on the power stage beyond its protection limit. The software trip catches sustained overcurrent, as opposed to the instantaneous hardware trip of code 25.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseA hardware protection circuit tripped on overcurrent at the inverter port. It acts independently of the firmware and reacts to fast transients such as load inrush or a surge.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
Internal components failed. Invert soft start failed.
CauseInternal components failed — the inverter stage could not complete its soft-start ramp to the working voltage.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe DC component riding on the inverter's output current exceeded the permitted limit — the output waveform has developed an asymmetry, typically from an output-stage or current-feedback fault.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe inverter-stage current sensor returned an out-of-range or implausible reading, so the control board can no longer trust its inverter current measurement.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe internal DC bus voltage fell below its operating range. The bus is regulated entirely inside the unit, so a persistent low reading points to an internal conversion-stage fault rather than external wiring.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
AC Surge or internal components failed. Bus voltage is too high.
CauseAn AC surge or failed internal components pushed the internal DC bus above its protection ceiling.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
Internal components failed. Bus soft start failed.
CauseInternal components failed — the DC bus could not be brought up to its working voltage during the soft-start ramp.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseInverter internal temperature has exceeded the safe operating threshold. Causes include high ambient temperature, blocked cooling vents, failed cooling fan, or installation in direct sunlight.
Recommended fixCheck whether the ambient temperature is too high.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe temperature inside the enclosure exceeded its limit — high ambient temperature or blocked airflow is the usual reason.
Recommended fixCheck whether the ambient temperature is too high.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseGround leakage current above the safety limit was detected — insulation or grounding on the PV or AC side is letting current return outside the normal conductors.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseThe leakage current sensor returned an out-of-range or implausible reading, so the inverter can no longer verify that its leakage protection is working.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseA fault has been detected in the PV input stage — usually a short, ground fault, or isolation failure between the PV array and the inverter chassis. Wet connectors, damaged cable insulation, or moisture in a junction box are common causes.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseA safety relay inside the inverter has failed self-test or is stuck. The inverter is designed to refuse grid connection in this state, so this is not an issue you can clear with restart cycles.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 38
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fixTest the parallel communication line, restart still have problems please contact the after-sales service.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseThe unit lost contact with the parallel host (master) inverter — usually a fault on the parallel communication line or the host powering down.
Recommended fixTest the parallel communication line, restart still have problems please contact the after-sales service.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseThe synchronization signal shared across the parallel communication line is abnormal or missing, so the units can no longer lock their outputs together.
Recommended fixTest the parallel communication line, restart still have problems please contact the after-sales service.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseThe paralleled inverters are running different firmware versions; every unit on the link must match before the group will run.
Recommended fix1. Update all inverter firmware to the same version. 2. Check the version of each inverter via the LCD settings to ensure that the CPU versions are the same. if it is not the same, please contact after-sales personnel to update the firmware. 3. After updating, if the problem still exists, please contact after-sales.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseThe parallel configuration is set up wrong across the group — typically a mix-up between single-phase parallel and three-phase group settings on the units.
Recommended fixSingle-phase parallel system and group three-phase system setup error.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseAnother inverter in the parallel group has an active fault, so the whole system reports a group-level failure until that unit is cleared.
Recommended fixSpecific faults in other machines in the parallel system.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseOne unit in the parallel group was detected absorbing power from the others (negative power flow), which the protection treats as a load-sharing fault and shuts down.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseA read/write error occurred in the EEPROM that stores the inverter's settings and calibration, so the control board cannot reliably save or recall its configuration.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseThe battery's BMS is refusing discharge — it has signalled over the communication link that the pack must not be drawn down, and the inverter stops discharging automatically.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseThe battery's BMS has requested charging over the communication link — the pack needs energy, and the inverter starts charging automatically.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseThe PV1/PV2 parallel-mode setting does not match how the strings are actually wired — the unit expects paralleled inputs and does not see them, or the reverse.
Recommended fixPlease confirm whether PV1 and PV2 need to be set to parallel mode. if not, please turn off this function in APP. if necessary, please confirm whether the wiring of PV1 and PV2 is connected to parallel mode.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseAn internal temperature sensor is no longer detected, so the inverter has lost a measurement it needs for thermal protection.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
CauseThe BMS firmware version does not match what the inverter's protocol expects, so battery communication cannot run reliably until the BMS is updated.
Recommended fixUpgrade the firmware of BMS.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 37
CauseThe battery input circuit failed its self-check — the path between the battery terminals and the internal DC stage is not behaving as expected, which points to an internal fault rather than the battery itself.
Recommended fixRestart the unit, if the error persists, contact the repair center.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 39
BMS doesn't allow inverter to charge battery (LCD information code shown during BMS communication).
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fixInformational; inverter follows BMS instruction.
Source:T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf· page 17
Send us the code on your screen and a Felicity technician will reply with the exact steps for your unit. Support is free for life — a first diagnosis never needs a callout.
Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.