A friend's air conditioner ruined his upstairs ceiling the other day and it made me remember to warn you about this.
If the indoor part of your air conditioning system -- called the air handler -- is located in the attic, it's a good idea to check its drain system occasionally.
Here in the South, a big part of your AC's job is to remove humidity from the air. That moisture goes through the ductwork and into the air handler where collects on the cool coil inside. It then drips down and exits a drain in the unit. The drain should be plumbed with a pipe that takes the moisture outside.
Since the unit has a ceiling underneath, it should have a backup drain system. If the indoor unit is installed properly, it will have a sheet metal pan below to catch the water in case the primary drain fails.
But many times, the backup system doesn't function. That's what happened to my friend.
The drain pan may also have its own pipe that's plumbed to the outside. Problem is, many times blown attic insulation gets in the pan and stops up that pipe. You should check and make sure the drain pan is clear of debris and that the pipe connected to it is open.
The primary drain is probably plumbed to a "hidden" location. The outside end of the backup drain pipe should be placed where you'll notice it dripping. That way, you'll know something's up with the primary drain.
The alternative fail-safe method is for the pan to have an electromechanical float switch that cuts the unit off if the pan gets full of water. With the unit running, use your finger to trip the lever on the float switch and make sure the unit cuts off.
Here's hoping you never have unsightly water stains on the ceiling.
