Unit turns on but compressor does not start; only the fan runs and air is not cold.

Safety: Compressor circuits carry high voltage. Disconnect power before opening the outdoor or rear panel.

Steps:

• Listen for sounds: When cooling is selected, listen for a click (relay) and compressor hum. A brief hum then click-off suggests a capacitor or compressor issue.
• Check voltage: Have a qualified person verify correct supply voltage at the unit.
• Inspect capacitor: On non-inverter units, locate the compressor run/start capacitor. If it is bulged or leaking, replace it with the exact microfarad rating.
• Check wiring: Inspect compressor terminals and wiring for burns or loose connections.
• Professional tests: A technician should test compressor windings and, on inverter units, the inverter module output.

Note: Do not repeatedly attempt to start a non-starting compressor; this can cause further damage.