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HVAC Troubleshooting

Follow our interactive troubleshooting guide to find answers to your system’s problems. Choose from a selection of common HVAC issues or pick your product for help with fixes you can try yourself.

AC Drain Line Clogged? Here’s What You Can Do

When dust, dirt, and other particles build-up on your AC drain line over time, it can cause a clog that disrupts your entire air conditioning system from functioning properly. Luckily, a clogged AC drain line is a common problem, and with some minor AC troubleshooting done by a professional, the issue should be resolved quickly. Not to mention, regular AC maintenance, done by both yourself and a professional, will help you avoid the pesky issue of a clogged AC drain altogether, leaving you an air conditioner that runs smoothly all summer long.

Symptoms of a clogged AC drain line

Your air conditioner works to remove heat and humidity from the air inside your home and places it outside, so you can feel cool and comfortable in your home. While a number of issues could be preventing your air conditioner from completing this job, one of the most common is a clogged AC drain line.

Your AC drain line, also known as a condensate line, is a white PVC pipe that runs from the indoor unit of your air conditioner all the way to the outside of your home. As your air conditioner cools your home, it builds up moisture and water in the drip pan, also called the drain pan. The drain line is responsible for taking that excess fluid out of the drip pan and safely depositing it outside, so the air conditioner can continue its cooling process. But, if the water in the drip pan grows mold or mildew, it can clog the drain line as it goes through. Additionally, general dust, dirt, or debris could get caught in the AC drain line, preventing it from functioning properly.  

The following symptoms are a good indication that you might have an AC drain line clog in your air conditioner: 

    How to unclog an AC drain line 

    If your air conditioner isn’t working, and you think your AC drain line is the culprit, it’s always safest to have an HVAC professional fix the problem instead of trying to troubleshoot it yourself. As soon as you notice a problem, turn off your air conditioner completely and contact a professional. When a technician comes to assess the drain line, they will likely start by checking the drip pan for any excess water build-up, and clean it out with a towel or vacuum. 

    Next, they’ll move on to the actual drain line. To unclog a condensate, or drain line, the HVAC technician will use a vacuum, wet vac, or simple snake to remove the clog. Similar to if you were unclogging a sink, when the HVAC technician unclogs your drain line, they should pull out a lump of, essentially, gunk that was causing the clog. Once the blockage has been removed, the technician will clean the drain line with PVC pipe cleaner and water. Before they leave, they’ll test the drain line and run your air conditioner to ensure the problem is resolved. 

    Tips to keep your AC drain line clear

    An important part of keeping your air conditioner running is keeping your AC drain line clear, which can be done with regular maintenance. Your air conditioner should be serviced by an HVAC professional twice a year, and during these routine visits, your technician will take action to keep your AC drain line clear. When an HVAC technician visits your home, they will clean the drip pan and check it for any leaks or water build-up. Plus, they’ll use traditional PVC pipe cleaner on the drain line to help prevent any potential clogs.

    If your AC drain line keeps clogging frequently, there are a few ways you can help mitigate the problem in addition to scheduling regular service with a professional. HVAC technicians can teach homeowners who face regular drain line clogs how to pour a cup of a household substance, like distilled vinegar, down their AC drain line to help prevent clogs. Additionally, keeping both your outdoor and indoor HVAC units free of debris, on and around the unit, will help prevent drain line clogging.

    AC drain line FAQs

    The more you know about your air conditioner drain line, the better equipped you are to keep it clean and clear. 

    Where is my AC drain line?

    Your AC drain line runs from the indoor unit of your air conditioner all the way to the outside of your home. You won’t be able to see the AC drain line from inside, but should be able to spot the white pipe somewhere outside your home.

    How do I unclog my AC drain line?

    If you suspect your AC drain line is clogged, do not try to unclog it yourself. Instead, contact an HVAC professional for assistance. Your technician will clean the drip pan, unclog the drain line with a snake, wet vac or other tool, then clean out the drain line with chemicals to help prevent future clogs.

    What happens if your AC drain line is clogged?

    If your AC drain line is clogged, your air conditioner can’t efficiently cool your home due to a blockage within the system. Some homes may have a drain pan condensate safety switch that will automatically shut down the indoor unit if the water level inside the drain pan begins to rise, in order to help prevent a clog. In that case, your system turning off or not running as it should might be a sign of a clogged drain line in your future. 

    But, if your system doesn’t have this safety switch, it will continue running with a clogged drain line. The water will eventually fill up the drain pan and begin to spill out, potentially leaking water and might even cause ceiling or drywall damage. Regardless of if your unit has a safety switch or not, if you suspect your AC drain line is clogged, turn off your system and contact an HVAC professional for help.

    What causes an AC drain line to clog?

    Your AC drain line can become clogged with mold and mildew that forms in standing water within the drip pan. Or, an AC drain line clog could be caused by general dust, dirt, dander or debris accidentally entering the drain line. 

    Can you snake an AC drain line?

    An HVAC professional can use a snake to remove a clog inside an AC drain line. Alternatively, a technician might also use a wet vac or vacuum to remove the blockage.

    Drain Line Clogged? Contact a Dealer

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