LG ductless-mini-split — LG single-zone systems in general service manual MFL41161610 Error Codes Directory

LG CH04: float switch error, or a missing jumper

CH04 reports the float switch circuit rather than a measured water level. On an indoor unit fitted with a float switch it points at drainage or the switch; on a model built without one it follows a short key missing from the float switch connector on the indoor board. Applies to: LG single-zone systems in general service manual MFL41161610 Whether your indoor unit has a float switch at all decides which half of this code applies, and that depends on the cabinet style and the exact model. Establishing it is the first thing document MFL41161610 asks a technician to do, which is why the characters alone cannot answer CH04 on any single-zone LG system. Owner-safe checks: Note whether water has appeared at or under the indoor unit, and whether the outside drain discharges during cooling. | Record the indoor model number, since whether a float switch is fitted at all depends on it. | Note any recent work at the indoor unit, particularly a board replacement or a service visit that opened the electrical cover. Qualified technician: The float switch connector, the short key, and the indoor board sit inside the electrical compartment and are technician work with the supply isolated. | Ask for the short key test described in the manual before an indoor board is quoted, because the manual conditions that replacement on it.