LG, the South Korean electronics company, makes ductless mini-splits, multi-zone systems that run several rooms from one outdoor unit, and central air conditioners for ducted homes. Most of it is inverter-driven and run by circuit boards, which makes LG systems quiet and efficient and gives them a particular set of failures. In Larkspur, San Rafael and Sausalito homes, an LG repair usually starts with an error code, a control board, or a refrigerant leak that has slowly sapped capacity.
LG equipment we work on
- Ductless mini-splits — a wall-mounted head, or a ceiling cassette, connected to its own outdoor unit.
- Multi-zone systems — two or more indoor units on one outdoor unit, each with its own remote or wall control.
- Central AC — ducted LG air conditioners and heat pumps that use the home’s existing ductwork.
Error codes and control boards
LG units report faults with codes shown on the indoor display or the wall controller. A code is a direction, not a diagnosis: it tells us which circuit tripped the protection, not which part failed. Control board malfunctions are a common LG complaint, and they deserve careful testing, because boards are often blamed for problems that start somewhere else:
| Code or symptom points to | Often actually caused by | What we test |
|---|---|---|
| Communication fault | Damaged or loose wire between units, poor connection at the terminal block | Wiring, voltage at the terminals |
| Sensor fault | Failed thermistor, corroded plug | Sensor resistance against its chart, connector |
| Inverter or compressor drive fault | Supply voltage problem, overheating, compressor issue | Supply voltage, heat sink, compressor windings |
| Unit dead, no display | Breaker, fuse on the board, surge damage | Power path, fuses, board inputs |
| High-pressure or overheat fault | Dirty outdoor coil, failed fan motor, blocked airflow | Coil, fan, clearances |
Only when the inputs and outputs prove the board itself is faulty do we replace it. That avoids paying for a board that fails again because the real cause was a wire or a sensor.
Refrigerant leaks
An LG system that cools a little less each month, runs longer than it used to, or pushes up the power bill may be losing refrigerant. The leak is usually at a flare joint, a service valve or a line set damaged during installation. We find it, repair it, evacuate the system and weigh in the correct charge; adding refrigerant without a repair only delays the next call. If your bills have climbed without a clear reason, see high energy bills and refrigerant leak.
Multi-zone: whole system or one room?
On a multi-zone LG system, the first question is how much has stopped. Every room down points to the outdoor unit, its power or its drive. One room down points to that indoor unit, its sensors, its line set or the valve that feeds it. Two rooms that seem to respond to each other’s remotes usually have crossed communication wires.
Keeping LG units healthy
Rinse the indoor filters every few weeks in heavy use, keep plants and debris clear of the outdoor unit, and have the coil and blower wheel cleaned about once a year. A clean system keeps its pressures and temperatures in range, which is easier on the electronics too. Our ductless mini-split service covers cleaning and repair.
How we work
We are independent and not affiliated with LG. You get an itemized price after the diagnosis, factory certified parts that carry the manufacturer’s warranty, and a labor warranty on our work. Same-day service is usually possible when you call before noon.