Noise (hissing, swishing, gulping) [air conditioner]

Note Normally, flowing or blowing sounds are primarily caused by the flow of refrigerant through the air conditioner. These sounds are normal and the noise will eventually stop.

Why you hear water flowing sounds when you turn the air conditioner on

When you turn the air conditioner on, the amount of refrigerant that travels to create cold air is increased, and its speed gets faster. At this moment, as the refrigerant moves, you will hear water flowing noise sounding like “gulping sound”.

This is a normal sound generated when the air conditioner operates. The closer you get to the target temperature the less noise will be generated to completely disappear finally.

Why you hear water flowing sounds when the air conditioner stops

When operating the air conditioner, the refrigerant flows along the pipe from the outdoor unit to the inside air conditioner head unit(s). And, when the air conditioner is stopped, instantaneously, the refrigerant pressure is evenly distributed to make sure that it does not rush to either one of the outdoor unit or inside air conditioner head unit(s). Therefore, after the air conditioner stops operating, you might hear water flowing noise sounding like “gulping sound”.

• As the refrigerant is evenly distributed over the pipe, the noise will be reduced then completely gone.

• If you had a drain pump installed along with the air conditioner, then it might be a problem with the drain pump.

• If the noise from the drain pump becomes suddenly louder, then consult with the pump installation contractor or drain pump manufacturer.