HVAC Troubleshooting: Pooling Water Under Air Conditioning

Posted on: June 27, 2016

If you notice a pool of water under your AC, it is a sign that your HVAC needs to be repaired or replaced. There are several things that can cause this common AC issue, so it’s important to call a certified HVAC technician to diagnose and repair the problem. 

Water is naturally created by the AC unit from the process of pulling in the hot/humid air from outside and cooling it through the unit’s cold evaporator coil. Condensation forms and that water is expelled by the drain line into your plumbing, condensation pump, or outside. If there is any issue with the parts that control this process, a pool of water will form under your AC unit. In this case, your AC is not running efficiently and could cause more expensive repairs, premature damage to parts and increased energy bills. Here are a few common causes for pooling water under AC:

  • Condensation pump – When the water is not expelled properly due to a faulty condensation pump, the continual presence of water in an AC unit will create mold and mildew build up and cause the system to clog. This is important to repair in a timely manner to prevent a snowball-effect of other problems because of a clogged unit.
  • Blocked drain hole – If condensation/water is not able to exit the unit due to a clogged drain hole, the water will have nowhere else to go but inside your home or pool around the unit. A clogged drain hole is caused by dirt, insects, debris or mold/mildew build up inside the unit. It could also be from a dirty evaporator coil in which case the dirt will mix with the water and fall down into the drainage pan, clogging the drain hole.
  • Frozen evaporator coil – Low refrigerant causes the coil to become much colder than necessary, in turn freezing it. A dirty air filter will also cause the coil to freeze from the lack of airflow. To defrost the coil, turn your AC off and call a licensed HVAC contractor to correct the problem.
  • Bad sealing – If the seals on your AC unit are not tight, it will cause an excess of air inside. The moisture from that air will build up when the warm air meets the cold air inside the AC unit. A HVAC contractor will need to reseal the outside of the AC to keep it properly isolated.
  • Poor installation – This is common with newly installed AC units. The problem of pooling water happens when condensate trap is not installed correctly, which will prevent the water/condensation from properly draining.

Action Air is dedicated to your home’s comfort and energy savings. If you are experiencing pooling water under your AC, call Action Air to schedule an appointment with one of our Nate-Certified technicians.