How to Check Drainage in a Central Air Conditioner

Your central air conditioner produces gallons of water on a daily basis as part of its normal operation. As air flows over your A/C’s evaporator coil, water condenses out and drips down into a collector pan underneath the coil. From there, it runs out through a condensate drain line that’s connected to your sewer pipe. Underneath the air handler is a secondary collector pan with a separate drain line to carry the condensate away if the main line gets blocked.

A once-a-month check that your A/C drain lines are running freely can help prevent serious problems such as:

• Foul sewer odors wafting from your A/C vents caused by a dry trap on an improperly installed drain line.
• Costly water damage to your home and belongings from backups due to blocked lines.
• Clogged condensate lines that allow toxic mold to flourish and spread to your ducts and into your air supply.
• Condensate backups that trigger a system shutdown and leave you without cool air until your HVAC contractor arrives and resets the overflow sensor.

Checking the condition of your condensate drain lines is easy, just follow these four steps:

• Turn on your A/C at the thermostat and wait for 30 minutes.
• Go to your indoor unit and with a flashlight, check for any signs of water in the collector pan underneath the air handler.
• Find your main PVC drain line where it comes out of the sealed evaporator coil compartment and look for its clean-out “T”. Take the cap off the clean-out and insert a funnel into the fitting. Slowly pour a gallon of water into the funnel. If it flows through and doesn’t backup, you’ll know the main drain line is open and not blocked. Afterward, replace the clean-out cap.
• Check the auxiliary drain line to make sure it is free of debris or insulation that would clog it if it was needed.

If you’re experiencing central air conditioner drainage problems in your Coastal Bend home and need expert advice, contact us today at CCAC.

Our goal is to help educate our customers in Corpus Christi, Texas about energy and home comfort issues (specific to HVAC systems). For more information about air conditioners and other HVAC topics, download our free Home Comfort Resource guide.

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