LG Multi V Error Code List

Error 03 means an indoor unit has stopped receiving signal from its zone controller. The unit works, it just is not being told what to do.

Error 204 means the outdoor unit is receiving no signal from the heat recovery unit — the box that lets one zone heat while another cools.

Error 237 means the indoor communications PCB received nothing from the outdoor unit for over three minutes. An RS-485 communication fault.

Error 242 is a network error at the central controller. Your building management interface has lost contact, even if the units still run.

CH05 and CH53 are communication failures between indoor and outdoor units. Shown as 05 and 53 on the outdoor display. The most common source of LG callbacks.

CH52 is an inverter communication error inside the outdoor unit. Shown as 52 on the outdoor display — a different fault from the indoor-to-outdoor codes.

CH21 is inverter compressor overcurrent or an IPM fault. Shown as 21 on the outdoor display. Potentially the most expensive fault on a Multi V system.

CH26 means the compressor failed to start. Shown as 26 on the outdoor display. Often a drive or supply problem rather than a dead compressor.

Error 35 means low side pressure dropped far enough to shut the system down. Usually a refrigerant leak — but a failed expansion valve reads the same.

Error 150 warns that liquid refrigerant is at risk of flooding back to the compressor. It is a protective warning before damage, not after it.

Error 50 means the outdoor unit has lost a phase of its power supply. Usually an electrical fault rather than an HVAC one — and dangerous to force past.

Error 42 is a low pressure sensor fault — the sensor itself, disconnected or shorted, rather than an actual pressure problem in the system.

CH04 is a condensate drain fault on an indoor unit. The system stopped to prevent water overflowing into the ceiling below — which is the real risk here.

Error 51 is a combination ratio fault — the indoor units connected exceed 130% of the outdoor unit's rated capacity. Usually a design or fit-out problem.

Error 200 is auto pipe detection failure. The system cannot work out which indoor unit is on which heat recovery port — and it recurs after any PCB replacement.