Troubleshooting

What every LG mini split error code means, from CH01 to CH67, checked against LG documents: what you can check yourself, when to call a technician and what repairs cost.

A heat pump blowing cold air in heat mode is often doing exactly what it was designed to do. The most common reason is a defrost cycle, which typically lasts 5 to 10 minutes. The second is expectation: heat pump air usually leaves the vents at 85 to 100°F, compared with 120 to 140°F from … Read more

A Trane heat pump blinking light isn’t automatically bad news. On the outdoor unit’s defrost control board, one flash per second means normal operation. Faster flashing, at two, three or four flashes per second, means the board has detected a problem with the defrost system or the refrigerant circuit. Before you decode a Trane heat … Read more

Carrier heat pump fault code 84 means “High Pressure Lockout for 4 Hours” on Infinity variable-speed models. The outdoor unit’s high-pressure switch has tripped repeatedly, so the control shuts the heat pump down for four hours to protect the compressor. It’s easy to confuse with code 83, which is the low-pressure lockout. Carrier heat pump … Read more

Daikin error code U4 means the indoor and outdoor units of your mini split or heat pump have stopped communicating. Daikin’s official code list calls it a “malfunction of transmission between indoor and outdoor unit.” The system shuts down because the indoor side can no longer tell the outdoor side what to do. The good … Read more

If your Mitsubishi mini split has stopped and is showing a code like P8, E6 or U4, the first letter already tells you most of what you need. P codes point to the indoor unit. E codes mean two parts of the system have stopped talking to each other. U and F codes come from … Read more