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How to Remove Algae From an Air Conditioner

Kenneth Coppens

Air-conditioning units, found in homes both old and new, may seem like maintenance-free appliances. This erroneous mindset can result in damage to a home that a simple maintenance procedure could have prevented. Air conditioners create condensation that generally passes through a drain pipe that empties outside. Due to the constant moisture produced by the condensation, algae can form clogs in an air conditioner's drain pipe, blocking it. This causes water to back up and overflow inside the house, resulting in water damage to walls, furniture and floors. Fortunately, algae problems are a "quick fix," with the right tools.

Air-conditioner drains must be cleaned regularly.
  1. Locate the outside drain line near the air-conditioner unit.

  2. Remove the paper filter from a wet/dry vacuum cleaner, as the algae may ruin it. The filter is typically located in the top of the device, just below the hose connection. Read the manual for your vacuum model if you are unsure how to open the vacuum housing.

  3. Place the vacuum cleaner directly beside the drain line. Plug the vacuum cleaner into an electrical outlet, using a heavy-duty extension cord if necessary.

  4. Hold the vacuum cleaner hose against the opening of the drain line. Wrap a towel tightly around the connecting point to create a seal.

  5. Turn on the vacuum. Let it run for five seconds to suck out the algae.

  6. Locate the drain pipe access point on the inside of the house. This should be located directly on the other side of the wall from the outdoor drain pipe.

  7. Pour 1 cup of bleach into the pipe to kill any remaining algae. Repeat this process every spring to prevent algae buildup.