LG Mini-Split Code CH25
Soft lockoutShown as: Outdoor LED01 (red) blinks 2 times, LED02 (green) blinks 5 times
AC low / high voltage. The line voltage feeding the outdoor unit is outside the acceptable range, so the unit shuts down to protect the inverter.
Manual wording: “25 AC Low / High Voltage”
Documented for: LG Multi F / Multi F MAX outdoor units and LS091HSV / LS121HSV single-zone systems
Likely causes, most common first
- Voltage to the system is too low or too high
What you can safely check yourself
- Check the breaker is fully on and not partially tripped
- Check the outdoor disconnect switch is on
- If the house has just had a brownout, surge, or power outage, turn the system off at the breaker for three minutes and back on
When to call a technician
If the code returns, an electrician or HVAC technician needs to measure the supply voltage under load. Persistent low or high voltage is a house wiring or utility problem, not a unit problem.
A LG mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- MULTI F / MULTI F MAX Outdoor Unit Installation Manual (LG Electronics U.S.A., Inc., Multi F and Multi F MAX multi-zone heat pump outdoor units (LMU series) with standard wall-mount, Art Cool, cassette and ducted indoor units) · checked 2026-08-25
- Defining Common Error Codes - Standard Wall-Mounted High-Efficiency Single Zone Systems (LG Electronics U.S.A. - Commercial Air Conditioning, LS091HSV and LS121HSV systems (LSN091HSV / LSN121HSV indoor units, LSU091HSV / LSU121HSV outdoor units)) · checked 2026-08-25