Have you ever noticed a PVC line connected to your A/C unit or your roof, or a pipe sticking out the side of your home with water dripping from it? That is the Evaporator Coil drain pan drain line. That is where the water that sweats off the evapoator coil drains out of. This line becomes even more important during the Monsoon Season or when there is humidity in the air. As warm humid air goes accross your cold evaperator coil, the coil will begin to sweat. The more humidity in the air the more the coil will sweat and water will start pooring off the coil going into Evaperator Coil pan and out through the drain line. Here is where the TRAP becomes very important. When the trap is filled with water, it breaks the vacuum built up inside the Evap Coil compartment allowing the water to drain out during the run cycle (While the unit is running). Without a trap the unit will only drain during the off cycle (When the unit is not running) because the vacuum created by the blower will hold the water in. Now during the Mansoon Season, your unit will have much longer run times because it will be removing a lot of moisture from the air, so without a trap breaking the vacuum and allowing the water to drain out during the run cycle, the pan will overfill and run down the return air duct and can cause water damage to your sheetrock or cause the return duct to collapse. If you have any thoughts that your unit may not be draing properly or you just want the peace of mind that your drywall wont bubble up or come crashing down do to water damage, Ultimate Comfort will be glad to come out and make sure your unit is draing properly.