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Thursday, June 13, 2013

What causes an air conditioner to leak water? The answer is easier to understand when you realize that one of the primary functions of an AC is to remove water from your indoor air. Moist, humid air holds heat and makes it harder to cool your home. As the heat energy is extracted from the moist air, condensation forms when the warm air contacts the frigid evaporator coil. On a humid summer day, many gallons of water may be condensed out of the air. All that liquid has to go somewhere. If your system's working properly, the water travels down the condensate drain tube connected to your household drain system. If it's not—that’s what causes an air conditioner to leak water.

Here are some typical malfunctions:

  • Located beneath your indoor air handler, the condensate drain pan catches condensed water as it drips off the evaporator coil. The pan is attached to a drain tube or to a pump that conveys the condensate out of the drain pan and into a household drain. If the air handler is no longer level in its installed position, water may overflow the drain pan on one side instead of running down the drain tube.
  • Airborne spores circulated through your air conditioning ductwork and deposited into the drain pan may spawn mold growth. Mold or algae accumulation can quickly plug the condensate drain line, leading to water overflow. Have your HVAC contractor inspect and clean the drain system annually, including placing time-release biocide capsules in the pan to prevent drain-clogging mold growth.
  • A defective condensate pump may also result in an overflow. If your drain pan is accessible, you can test the pump by pouring water into the pan and listening for the sound of the pump energizing as the pan fills. If you can’t hear it, don’t run the air conditioner until a qualified AC service technician has diagnosed the problem.

In Chicago, Northwest Indiana and Southwest Michigan, the professionals at are your neighborhood heating and cooling specialists. Call us for more information about what causes an air conditioner to leak and how we can stop it.

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