Haier ESA410M ユーザーズマニュアル

While your air conditioner is operating, it is normal to hear the following sounds:
Your new air conditioner is designed to give you many years of dependable service. This section 
tells you how to clean and care for your air conditioner properly. 

Air movement 

Air rotating around the fan.

Window vibration

Installation not correct. Refer to Install section

Pinging

Water droplets being thrown against the condenser (outside) coil. This 
helps cool the condenser coil.

High pitched hum

The compressor turning on and off.

Clicking

The thermostat turning on and off.

Gurgling

Refrigerant moving through the evaporator (inside) coil.