How to Test Air Conditioning Piping for Leaks

All air conditioners contain freon that produces the cool air that flows into the vehicle or the home. The freon flows through all of the system's necessary components to turn the freon liquid into a vapor. Over time, the air conditioner system can develop leaks that can be visually seen on those components. There can be leaks that can be hard to detect with the naked eye and will require a type of leak-detection device to locate them.

Things You'll Need

  • Safety glasses
  • Flashlight
  • Chalk
  • Refrigerant leak detector
  • Turn on the air conditioner and turn all of its controls to the on position. Move the air conditioner fan speed selector to the high position.

  • Inspect the air conditioner pipes thoroughly for any visual signs of leaks while wearing safety glasses. Use a flashlight if necessary. Look for dark, wet stains on the pipes. Mark any locations of the leaks with a piece of chalk.

  • Turn off the air conditioner and re-inspect the air conditioner pipes for leaks while the system is off. Mark any leaks you may find with chalk.

  • Turn the air conditioner back on and turn the air conditioner fan speed to the high position. Set the refrigerant leak detector to the "Find Leaks" setting. Use the flexible end of the refrigerant leak detector to check the air conditioner pipes for leaks. Begin at the end of one of the air conditioner pipes and hold the end of the flexible line that is attached to the leak detector about a half-inch from the air conditioner pipe.

  • Move the flexible end of the leak detector slowly down the entire air conditioner pipe. If the leak detector detects a leak, its alarm will sound. Continue moving the end of the leak detector up and down the pipe to check for leaks. Be sure to keep the end of the leak detector about a half-inch away from the pipes for a more accurate leak detection. Mark any leaks revealed by the leak detector with chalk.