Why Is My Air Conditioner Spraying Water?

Origins of Water in the System

• Any water found in your air conditioning system comes from condensation accumulated on the copper coils. Air conditioners cool by blowing indoor air across copper coils filled with cold refrigerant. These coils "sweat" in much the same way a cold glass of water sweats in a hot room. The water then drains from the coils in to a condensate pan, which contains a drain to the outside. Air conditioners do not have any water in their mechanism outside of condensate, so any water leaks in your unit are involving this portion of the system.

Central Air Conditioning Condensate Drain Clog

• If your central air conditioning condensate drain becomes clogged, water can back up in to the system. In most newer air conditioning units, this will cause the system to shut down, but in older models, water can make its way into your duct work. If you have water leaking through your cold air registers, this is the most likely source. Examine your condensate pan and drain to make sure it is draining properly, use compressed air to blow out the condensate drain from the unit's side.

Improper Installation of Window Unit

• A window unit that is not seated in its window properly will leak water back in to the house and can actually spray water if water gets on the circulation fan. Window units are constructed in such a way that, when properly installed, they slope slightly toward the outside of the house. This allows condensate to drain to the back of the unit and safely drip away from the home. If the window unit is installed improperly, water can actually drain back in to the home.

Malfunctioning Condensate Pan

• If your condensate pan has been disturbed, it may not be draining into the condensate drain properly. It is a relatively delicate mechanism, in that it is typically constructed of sheet metal and is carefully sloped to allow water to drain through a hole in its center. If you have recently been moving boxes around your unit in the attic or doing renovations, consider checking to see if the pan has been moved and adjust it accordingly. Ensure that water drains through the center drain by pouring a small amount of water in the pan.