Origin of Water in the System

• Air conditioners do not contain water in their cooling mechanism; it is a byproduct of their cooling system. Air conditioners take in air from inside the home and blow it across cold coils filled with Freon. These coils "sweat," in much the same way a glass of cold water will sweat in a hot room. This sweat is the humidity in the indoor air being removed. It drips down in to a condensate pan, which then drains outside the home. This is why, on especially humid days, an air conditioner can be seen to put out significantly more water.
  
  

Clogged Condensate Pan

• Most central air conditioners have user-serviceable condensate pans. They are located directly beneath the coils, and their exact location should be indicated in the service manual. Ensure that the pan is seated firmly, and that the hole in the low part of the pan, the drain, is not clogged. If an air conditioner is run without a filter for a prolonged period of time, hair and other debris can reach the condensate pan and clog its drain. The pan then overflows, causing a leak from the air handler. Clean out the drain and see if the leaking has ceased.
  
  

Unseated Condensate Drain

• The portion of the condensate draining system attached to the condensate pan drain is the drainpipe that runs outside your house to dispose of the water. This pipe can become loosened or slip off the condensate pan drain. Ensure it is firmly attached and that there are no obvious cracks or splits at the coupling.
  
  

Clogged Condensate Drainpipe

• A clogged condensate drainpipe will cause water to back up and overflow inside the condensate pan, creating a leak at the site of the air handler. Remove the condensate drainpipe from the pan and use compressed air to blow the clog out from the air handler's end. Use a funnel to pour water down the pipe and have someone outside the house ensure it flows freely from the other side of the drainpipe. Reattach the condensate drainpipe and check to see that the leak has stopped.