Over temperature
Also displayed as F18 on some models.
Fault — the inverter cuts its output and the red LED stays solid until the fault is cleared.
The exact meaning depends on your model:
Also applies to:IVPS2512IVPS2524IVPS3524IVPS5024IVPS5048IVPS7548IVPS-7548IVPS10048+9
Over temperature — The internal temperature of the inverter is too high.
Cause: The inverter has overheated.
Source: IVPS-IVPM User Guide.pdf, p.17 · ivps3524p1g1-lv-ivps5048p1g1-lv-ivps7548p2g1-ivps10048p2g1-manual.pdf, p.24
Also applies to:IVGM6KL-P1G1IVGM7K6L-P1G1IVGM8KL-P1G1
Battery Under Voltage Alarm — Battery voltage is too low, the battery should be charged.
Cause: Battery voltage has fallen to the low-voltage alarm threshold — the pack is nearly depleted and needs charging before the inverter cuts off discharge.
Source: Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf, p.51 · Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf, p.53
Also applies to:IVEM6048
Over temperature happen at PV circuit
Cause: The temperature of internal PV converter component is over the limitation.
Check whether the air flow of the unit is blocked or whether the ambient temperature is too high.
Source: felicitysolar IVEM 6048 Solar Inverter User Guide.pdf, p.37
Also applies to:IVEM12048-IIIVEM 8K-12K Series IIIVEM8048-LVIVEM8048
Over temperature happen at PV circuit
Cause: The temperature of internal PV component is over the limitation.
Check whether the air flow of the unit is blocked or whether the ambient temperature is too high.
Source: IVEM8K-12K-II_compressed.pdf, p.43 · FelicitySolar IVEM8048-LV Single Phase Hybrid Inverter User Guide.pdf, p.38
The output overcurrent is abnormal
Cause: The inverter's output current ran above the protection limit — an overload or surge on the connected loads, or a fault in the output stage's current control.
Restart the unit, if the error persists, contact the repair center.
Source: t-rex-10klp3g01-inverter-user-guide-english.pdf, p.28
Battery 1 Undervoltage fault — Battery 1 voltage is too low, the battery should be charged.
Cause: Battery 1 voltage has fallen below the permitted range — the pack is deeply discharged and must be charged before normal operation resumes.
Source: t-rex-25-50khp3g01-user-guide-en.pdf, p.46
SampSensor is error — Fault event: sampling sensor (current/voltage sensing circuit) error.
Cause: The current/voltage sampling sensor returned abnormal values — an internal sensing-circuit fault.
Source: LUX-S-1600LG01.pdf, p.22
Also applies to:LUX-Y-48100HCG01LUX-Y-48100HMG01LUX-Y-48100HR13G01LUX-Y-48100HR9G01
Relay Adhesion Fault — Main relay contacts have welded/stuck (relay adhesion).
Cause: A 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.
Restart, if the fault still exists, contact our engineer.
Source: LUX-Y-48100HG01-Lithium-Battery-User-Guide.pdf, p.20
Relay Adhesion Fault
Cause: A 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.
Source: LUX-Y-48100HG01MN User manual 358-S010025-03 0325(V2.0).pdf, p.27
It depends on the model — 11 devices use code 18. On the IVPS/IVPM Series it means: Over temperature. The card for each model on this page gives its exact meaning and fix.
18 is a fault code: the inverter cuts its output and the red LED stays solid until it is cleared.
Turn off the inverter and let it cool down. After the temperature is back to normal you can use it again. The exact steps for each affected model are listed on this page.
Prefer the full written guide? Read the complete Felicity inverter error-code guide
Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.