In most air-conditioning systems, the condenser unit is located outside and is prone to accumulate dirt and debris from trees, and airborne dust. The condenser has a fan that moves air across the condenser coil. You must clean the coil on the intake side, so, before you turn off the power to the air conditioner, check to see which direction the air moves across the coils.
Here’s how to clean the condenser:
Step 1: Cut down any grass, weeds, or vines that have grown around condenser unit; they could be obstructing airflow. Keep an area clear of at least three feet on all sides.
Step 2: Turn off the power to the unit. A disconnect should be within site on a wall.
Step 3: Clean the condenser coil with commercial coil cleaner, available at refrigeration parts supply. Coil cleaner with a mild citric acid is the strongest chemical you should use. Instructions for use are included. Be careful not to force dirt into the fins where it can become lodged and block air flow. Flush coil clean being carefully not to bend or damage the delicate aluminum fins. Rinse the entire cleaner from the coils.
Step 4: Clean fins with soft brush to remove accumulated dirt. You may have to remove a protective grille to reach them. Clean fins carefully with garden hose, being careful not to bend the delicate fins with excess pressure. Clean fins very carefully: They’re made of light-gauge aluminum and are easily damaged. If fins are bent, straighten them with a fin comb, sold at most refrigeration parts stores. A fin comb is designed to slide into spaces between fins. Count the fins per inch on your coil to get the right size. Use it carefully to avoid damaging fins.
Step 5: Check concrete pad on which condenser rests to make sure it’s level. Set carpenters’ level front to back and side to side on top of unit. If pad has settled, lift pad with pry bar or piece of 2 x 4, then force gravel or rocks under concrete to level it.
During the fall and winter, outside condenser units should be protected from the elements to prevent leaf blockage and ice damage. Cover the condenser unit with a commercial condenser cover made to fit the shape of the unit or use heavy plastic sheeting secured with sturdy cord.