Central Air Conditioner Drain
- A central air conditioner that is leaking water back into the house may have a clogged drain. Check your outside walls for a small piece of PVC or tubing that drips water when your unit is running. This is your condensate drain for your central air unit. If this pipe becomes clogged, water can back up and flood your condensate pan, causing it to overflow. Ensure the drain is not clogged by detaching it from the unit and blowing compressed air through it.
Central Air Conditioner Pan
- If you have recently been working on your central air conditioner, or working around it, you may have accidentally bumped or moved the condensate pan. The condensate pan is basically a small metal dish with a low spot and a drain in the center. If the pan is bent or tilted, water will fill the pan up and overflow, rather than draining through the center hole. Examine the pan and ensure water is draining from it, and that there is no standing water in the pan itself. Clean out the center hole, and ensure the pan is properly seated.
Window Unit Improper Installation
- If a window air conditioner is not installed at the proper angle, its condensate pan can be tilted back toward the window. This can cause water to overflow from the pan back in through your window, rather than draining outside. Ensure that your unit is installed so that it is tilting away from the house at a slight angle, when viewed from the outside. Examine the bottom of the unit's case, and see to it that the drain is not clogged.
Word of Warning
- Central air conditioners and window units are complicated appliances that contain hazardous gas under extreme pressure as well as high-voltage wires. Do not attempt to remove or disassemble your unit. Check the user-serviceable causes of an indoor leak, such as clogged drain holes and drainpipes, and then call a licensed service center to further diagnose the problem.