If your air conditioner is making a gurgling sound even when it's turned off, there might be a few possible explanations:
Residual water: Air conditioners remove moisture from the air as part of their cooling process. Some of this moisture can condense and collect in the unit's drainage system or pan. If there is water trapped in the drain pan or other components, it can produce a gurgling sound as it slowly drains away even after the unit has been turned off.
Refrigerant movement: Air conditioners use a refrigerant to cool the air. Sometimes, when the unit is turned off, the refrigerant may still be circulating or equalizing pressure within the system. This movement can cause gurgling noises, especially if there's a slight refrigerant leak.
Pipe expansion/contraction: The air conditioner's refrigerant lines and pipes can expand and contract with temperature changes even when the unit is off. This expansion and contraction might produce gurgling noises as the refrigerant moves through the lines.
Air in the system: Air bubbles or pockets trapped in the refrigerant lines can cause gurgling sounds as the air moves through the system.
Defective components: If there is a malfunction or damage to certain components within the air conditioner, such as the condenser or compressor, it might cause unusual noises, including gurgling sounds.
If the gurgling noise is persistent or accompanied by other issues like reduced cooling performance or leaks, it's best to have a professional HVAC technician inspect and diagnose the problem. They can identify the root cause and perform any necessary repairs to ensure your air conditioner functions correctly and efficiently. Additionally, regular maintenance can help prevent such issues and keep your air conditioner in good working condition.