LG Air Conditioner Error Code CH04

CH04 on an LG air conditioner indicates a drain pump or float switch error. The unit has detected either an actual water overflow condition in the condensate pan, or an open circuit in the float switch that the control board interprets as an overflow. The system shuts down as a safety precaution to prevent water damage. Diagnosis involves checking water level, drain line flow, float switch resistance, and drain pump operation.

No, you should not attempt to bypass or ignore CH04. The error exists to prevent condensate from overflowing, which can cause water damage to ceilings, walls, and flooring, and can create conditions for mold growth. Leave the unit off until the root cause has been identified and corrected.

Repair costs vary depending on the cause. Drain line cleaning or a simple wiring fix by a technician typically runs in the range of $75 to $150 for a service call. Replacing a float switch generally costs between $50 and $150 including parts and labor. A drain pump replacement can range from $150 to $350 or more depending on the unit model and labor rates in your area.

Some causes of CH04 are DIY-friendly. Clearing a clogged drain line, cleaning the condensate pan, and reseating loose wire connectors can often be done without special tools. However, testing float switch resistance requires a multimeter, and replacing the drain pump or float switch involves working with internal wiring, which is better suited to a technician if you are not comfortable with electrical components.

A power reset may temporarily clear the CH04 code, but the error will return if the underlying problem has not been fixed. If the condensate pan is full, the float switch is faulty, or the drain pump is not working, the fault condition persists after reset. Always resolve the cause before resetting to avoid repeated shutdowns or potential water damage.