Why Is My AC Unit Leaking?

Your air conditioner plays a critical role in keeping your home comfortable and safe through the summer. As it works, the moisture from the warm air condenses on the evaporator coil, which then drips from the system. Most of the time, the drip pan catches and drains it away through the condensate drain. Consider these seven causes of water leaking from your system instead of properly draining.

1. Clogged Condensate Drain

One of the primary causes of AC water leaks, and one of the easiest to solve, is a clogged drain. These will eventually clog due to dust, dirt, mildew and other contaminants, causing a backup of the condensate, which will leak out. Preventing a clog simply means routinely cleaning the drain. A technician will do this during a routine maintenance visit.

You can also clean your condensate line more frequently if you desire to do so. Find the access for the condensate line, usually a T-shaped vent tee with a cover or cap. Remove that, and pour 1/4 cup of straight distilled vinegar into the access. Wait about 30 minutes, then flush with water. The acid in the vinegar should dissolve or loosen any contaminants and allow them to come out. If the drain appears clogged, call a professional technician to mechanically clear the drain.

2. Low Refrigerant Charge

Your air conditioner needs a specific refrigerant charge to work properly. The system gets too cold when there’s insufficient refrigerant, especially at the evaporator coil. This causes the condensate to freeze on the coil, eventually shutting the system down to prevent damage as it restricts airflow. When the system thaws, the condensate from the melted ice may overwhelm the drain, causing it to overflow and leak. A qualified technician will check the refrigerant charge during routine maintenance and let you know if it’s low. If it is, they will likely recommend additional testing to find the refrigerant leak being it’s a sealed system under normal conditions.

3. Dirty Air Filter

Air filters are often the most neglected part of maintenance, sometimes staying clogged in the system for months. A clogged air filter restricts the airflow through the system, which prevents the refrigerant from absorbing heat, causing the evaporator coils to get too cold. This can cause a similar freezing issue as low refrigerant, which then leads to leaking. Check your filter monthly and plan to change it every 30 to 90 days if you have a 1- or 2-inch filter.

4. Exposed Refrigerant Lines

Most of your visible refrigerant lines should be covered in foam insulation to prevent condensation from forming on them. However, sometimes that insulation gets old and brittle and may fall off, exposing the lines. This can cause freezing on the pipes, especially if there’s a leak in the system. When this thaws, it often produces moisture where the drip pan can’t catch it, leading to what looks like leaking.

5. Poor Installation

Proper AC installation is critical to it running effectively. This includes ensuring that the unit is installed on a level surface to prevent unusual strain. However, it also means ensuring that the drip pan tilts appropriately to direct condensate to the drain hole. Installing an air conditioner without this attention to detail can cause the condensate to miss the pan altogether or direct the condensate away from the hole, both of which cause what looks like leaking.

6. Damaged Condensate Drain Pan

The most commonly used drip pan in the United States is an acrylic-coated galvanized steel. This can eventually break down, separating the bond between the acrylic and the metal. In some cases, you may develop holes in the drip pan, allowing the condensate to leak out rather than drain properly.

7. Faulty Condensate Pump

Depending on your AC model and its location, you may have a pump to help move condensate through the drain. Like other mechanical parts of your system, this will eventually fail but will do so prematurely if there’s a switch issue causing the pump to run while dry. A maintenance technician will check the pump during routine professional maintenance if you have one installed in your system.

Alps Heating & Air Conditioning, Inc. has been the HVAC service provider of choice for property owners around Anaheim since 1979. Our award-winning team offers heating and air conditioning repair, maintenance and installation together with attic insulation installation, duct design, water heater installation and repair and indoor air quality solutions. Call to schedule your air conditioning maintenance or repair appointment with one of our NATE-certified technicians today.