LG Mini Split H04 Error Code

Updated 2026-08-30 · review status: manual-verified · reviewed by MiniSplitDecoder Editorial Team Last verified: 2026-08-30

Check your model first

  • LG official support (ceiling-mounted CH03/CH04 article)
  • Independent LG code references (MyPros+, TechFaultFix, BC Wide)
  • Wall-mount note (ErrorCodeFixes)

Match the model on your equipment label to the linked manufacturer documentation. The same code can mean different things across model families.

Quick answer

LG H04/CH04 means a drainage problem: the drain pump is not operating, the float switch is open, or the unit detects water overflow in the drain pan. LG says to reset the unit once and call LG support if the code persists. Homeowners can safely check for visible leaks and a clean filter; the pump, float switch, and drain-line work are technician jobs.

Severity: medium · DIY difficulty: easy

Safety

Stop at the breaker power-cycle and any plug-accessible checks (filters, remote settings, visible wiring). The outdoor unit's capacitor holds a lethal charge and the refrigerant circuit is both pressurized and (on R-32 units) flammable — opening panels or servicing the sealed system is licensed-technician work (EPA 608).

What H04 means

H04 (CH04) means a drainage error on LG units: condensate is not being removed the way the control expects - the drain pump (where fitted) is not operating, the float/drain-level switch is open, or an actual water-overflow condition is detected in the drain pan. LG's own support page for ceiling-mounted units states CH04 'indicates a drainage problem'; on wall-mount models it appears mainly where an optional condensate pump is installed.

Code meaning varies by series

  • LG official support (ceiling-mounted CH03/CH04 article): CH04 indicates a drainage problem - reset the air conditioner; if it persists contact LG Support; do not disassemble or replace internal parts yourself
  • Independent LG code references (MyPros+, TechFaultFix, BC Wide): CH04 = drain pump or drain level/float switch error: real water overflow or an open float-switch circuit interpreted as overflow
  • Wall-mount note (ErrorCodeFixes): LG wall-mount units use a gravity drain or an optional condensate pump - verify pump operation where one is fitted; code is uncommon on gravity-drained wall units

First checks before service

This page currently documents the safe reset triage. If the code returns, use the linked source manual or a qualified technician for code-specific diagnosis.

  1. 1. One-time fault event (power disturbance or transient sensor reading) common DIY

    Check: Power-cycle at the breaker/disconnect (or unplug for CPAP), restore, and run the system while watching for the code.

    Fix: If the code does not return after a full run cycle, the fault was transient — monitor, no repair needed.

  2. 2. Fault persists after a clean reset occasional pro only

    Check: If the code returns immediately or every session, note the conditions (startup, heating, after rain).

    Fix: A persisting code points at the component the manual assigns to this code — that repair is technician territory.

Related codes

Cross-references for the same fault family, by brand:

LG H24 · LG H25 · LG H34

Commonly searched as: "lg h04" · "lg error code h04" · "lg air conditioner h04"

Sources

Related Mini Split guides

Mini-Split Communication Error: DIY Checks · Mini-Split Flashing Light Decoder: Blink Patterns · Mini-Split Leaking Water Inside? The Clogged Drain Fix · Mini-Split Maintenance Checklist: Seasonal DIY Tasks