Understanding HVAC Guidelines

Central AC Not Cooling Properly? Troubleshoot, Repair And Clean The Condenser Coil

23 February 2016

Marilou Girard

If your central air conditioning system puts out warm, humid air in the home instead of cool, comfortable air, you may have a problem with the outdoor unit's condenser coil. The condenser coil is an essential part of the air conditioning system that changes heated gas refrigerant into cool liquid refrigerant. If the condenser is dirty or damaged, it won't work properly. In many cases, a malfunctioning condenser coil can damage the compressor. Here's how you troubleshoot, repair and clean the condenser coil to cool your home. 

Why Is the Condenser Coil Important?

The condenser coil is the large, flat piece that lines the inside of the outdoor unit's cabinet. The coil not only releases heat from the unit and exchanges gas to liquid, it also protects the unit's internal parts from the damages caused by bad weather, dirt and foreign objects. It's important that you clean and maintain the condenser coil properly to avoid issues like those previously mentioned. 

In addition, the condenser coil relies on tiny, tooth-like aluminum structures called fins to perform the functions above. The fins cover the entire surface of the coil. If the fins clog up with debris or bend, they can't release heated air properly. The heat backs up into the compressor and causes a number of issues with your cooling system.

The compressor receives low-pressure refrigerant gas from the evaporator coil, then converts it to a high-pressure gas before sending it to the condenser coil to be cooled and liquified. If the condenser coil can't receive the heated gas or remove it from the unit, the compressor overloads from heat and breaks down. 

To prevent the problems above, clean the condenser coil's fins.

How Do You Clean the Condenser Coil Properly?

One of the first things you should do is disconnect power to the outdoor unit at the shut-off box, which sits somewhere close by the unit. Depending on the type of shut-off system you have, you may only need to pull a fuse from the box to cut power. Some shut-off systems require you to flip a switch from the "on" position to the "off" position. If you're unsure about how to cut power to the unit, turn the entire AC system off at the circuit breaker inside the house.

Next, allow the unit to cool down. The cool-down time may vary, so check the unit periodically by carefully touching the housing. After the unit cools, remove the outer cabinet from the unit with an electric or manual screwdriver, then place the cabinet upright near the house to prevent damage to the metal.

Now, follow the steps below:

1. Suction the dirt from the fins with a low-powered vacuum, then wash the fins with a garden hose. Don't press the vacuum's hose directly against the fins or turn the water hose on high to avoid damaging the fins. A low stream of water will work well to remove the debris.
2. Examine the cleaned fins for damage. If the fins appear bent, use a fin comb to repair them, which you can find at most hardware stores. Place the fin comb at the top of the coil, then gently draw it downward until you reach the bottom of the coil. 
3. Repeat step two until the fins straighten out. 
4. Recover the condenser coil, then return power to the cooling system.

If any of the fins appear mangled or severely bent during the cleaning, contact an air conditioning technician for services. Severely damaged fins won't operate efficiently and can actually damage the condenser by blocking the flow of heated gas out of it.

For more tips on how to cool a hot, humid home or maintain your condensing coil, contact a company like Cape Fear Air Conditioning & Heating Co., Inc.

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