How To Unclog A Central Air Drain System

If notice leaks or around your residential central air conditioner's outside unit, it has shut off, the drain system may be clogged. The job of the drain is to filter water outside, but it can get clogged with sludge. The sludge settles on the bottom because the condensate doesn't have enough force to dislodge it, which causes water backups.

A beginning DIY person should be able to easily fix the problem. Follow these tips to unclog the air conditioner drain system.

Prepare to Remove the Clog

For this project, you need the following:

  • work gloves
  • wrench
  • rag
  • wet/dry vacuum
  • funnel
  • plumbing snake
  • bleach
  • bucket

Turn off the power to the unit by unplugging the power cord, or turning off the breaker in the breaker panel. Look for two copper pipes close to the the unit just under the roof, or close to the home's foundation. You should now see a black, gray, or white PVC condensate pipe protruding from the wall.

Clean the Drain Pan and Condensate Pipe

Detach the housing panel on the outside unit to access the drain pan. The drain pan is commonly located at the bottom of the housing. Stuff a rag in the drain pan pipe to prevent water backup.

Set the wet/dry vacuum on "wet suction," and remove any filters. Suck the water out of the pan. Fill a bucket with water, and pour it down the drain to test. The water will flow down the drain easily if the clog has been removed.

Take the cap off the T-connector on the condensate pipe with a wrench. Insert the nozzle in the hole and suck the water out of the pan. Check the vacuum for sludge. Vacuum again, changing canisters as needed.

Turn the power back on, reattach the pipe connector, and try the unit again. If the unit is still clogged, proceed to use a plumbing snake.

Try a Plumber's Snake and Bleach

Turn the power off to the unit. Insert the tip of a plumber's snake in the condensate drain line. Keep pushing until you hit the clog. Rotate the snake back and forth several break the clog.

Funnel about one cup of bleach down the drain line to further dissolve the clog. To prevent future clogs, mix one-fourth cup of bleach,bleach with a gallon of warm water, and funnel it down the drain line..

Restore power to the unit, and reinstall the housing panel. If you don't trust your skills, or the unit still doesn't work, contact a plumber like Smedley & Associates, Plumbing, Heating, Air Conditioning.