Dehumidifier fan runs but the compressor never starts; the unit blows room-temperature air only.

Safety: Unplug the unit before opening the cabinet.

Steps:

• Check modes and settings: Ensure the humidity setpoint is below the current room humidity and that the unit is not in fan-only mode.
• Listen for relay: When the unit calls for dehumidification, you should hear a click from the control board. No click may indicate a faulty relay or control board.
• Inspect wiring: Trace wires from the main PCB to the compressor. Look for loose connectors or burnt wires.
• Capacitor check: If your Tosot model uses a run capacitor for the compressor, inspect it for bulging or leaks. Replace the compressor run capacitor if it is suspect.
• Board replacement: If the wiring and capacitor are good but the control board never sends power to the compressor, replace the main control board.