As air conditioners operate, they produce condensation: liquid water that settles out of the air that the unit cools. This condensate is funneled into a tube called the condensate drain tube, which carries it to a drain. Sometimes, the condensate drain tube becomes blocked, either by mold or by dust and other debris. This is one of the most common problems that air conditioners develop, so as a homeowner, it's important that you be aware of it and the ways that HVAC contractors fix it.

How do you know that you have a blocked condensate drain tube?

A blocked condensate drain tube won't stop your AC from working. In most cases, the AC unit will keep cooling your home as usual. As such, people sometimes overlook the blockage until it has been a problem for a while. But the signs are easy to recognize if you go look at your actual AC unit.

If your AC unit has a blocked condensate drain tube, there will be water on the floor around it. The water will be spilling out from the bottom or side of the indoor AC unit. Do check the liquid to make sure it is clear. If the liquid is colored, you have a refrigerant leak—which is a whole other type of problem. 

How do AC contractors fix a blocked condensate drain tube?

If your AC contractor arrives and confirms that your condensate tube is, indeed, blocked, then they may proceed in one of two ways. Usually, they will start by attempting to clear the blockage. Some do this with a tool that looks like a pipe cleaner. Others use a special suction device to suck out the grime.

If the HVAC contractor cannot clear the blockage, they will generally replace the condensate drain tube. They'll undo the fastener that holds it in place, and then slide the tube out. They'll cut a new section of tubing to the right length, attach it to your AC unit, and then tighten the fastener back up around it. 

After you have the tube cleared or replaced, make sure you sign up for annual AC cleaning appointments. By keeping the AC cleaner, you will help prevent the condensate drain tube from becoming blocked again. 

Condensate drain tubes do clog from time to time. While this will not stop your AC from working, it is definitely something you need to have an AC contractor address.

Contact a local AC repair service to learn more.