Why Is Your Air Conditioner Cycling On And Off So Often?

A central air conditioning system that is working properly should cycle on and off a few times per hour. If your system is cycling every few minutes (or even every few seconds), something is wrong. When your air conditioner short cycles, it wastes energy -- and it usually doesn't cool your home adequately, either. Follow this guide to get to the bottom of the problem.

The unit may be iced over.

Take a look at your air conditioner's compressor unit. (This is the portion of the system that's generally found outside.) Does it have a buildup of ice on it? If so, this is what's causing the short cycling. Turn your air conditioning system off to let it thaw out. Once the unit is thawed, you'll want to do a few things to ensure it does not freeze over again.

  • Change the air filter. A dirty air filter slows air flow through the compressor, allowing the coils to become too cold and freeze over.
  • Vacuum off the fins. If these are caked in dirt or grime, air flow through the unit might be inhibited.
  • Clear debris from around the unit. Brush, trees, and other plants too close to the unit may impede airflow and contribute to freezing.

Once these tasks are complete, you can turn the system back on. If it freezes again or starts short-cycling again, call your HVAC technician. Your coolant levels may be low, and they must be topped up by a professional.

The filter may be clogged.

Even if the unit is not frozen over, a clogged and dirty filter may be causing your air conditioner to short-cycle. Your air conditioner has to work extra hard to push air through a clogged filter. This could cause it to overheat, which triggers a shut-off mechanism. The unit cools down and turns on again, only to overheat again a few minutes later.

Locate your air conditioner's filter. This is usually found indoors where the main air return duct meets your blower unit. Pull the old filter out of the slot and slide a fresh one in. With any luck, your short-cycling problem will stop. Then, remember to keep up with changing the filter every one to three months to prevent future issues.

Your compressor might be leaking coolant.

A leaky compressor can also trigger short-cycling even if the unit does not freeze over. Low levels of refrigerant cause the air conditioner to work harder, which triggers an overheating cycle similar to the one that arises from a dirty filter. You can try to detect a refrigerant leak by placing some plain sheets of white paper under the edges of your compressor. Let them sit for a day or two (ideally, you would do this on days when it is not raining). If you see any colored fluid on the paper, this means you have a refrigerant leak. Usually, the coolant in a residential air conditioner is rose colored, but yours may be a different color.

Unfortunately, refilling your air conditioner's refrigerant coils is not a job you can tackle yourself. Doing so requires a special license. Plus, it is far too easy to add too little or too much refrigerant if you don't know what you're doing. Arrange for your HVAC technician to refill your refrigerant for you, and your short-cycling should end.

Your air conditioner's control board might be damaged.

What if your unit is not frozen over, your filter is fresh, and you don't detect a coolant leak? Chances are, your short-cycling is due to a malfunction of your air conditioner's control panel. An HVAC technician can examine your unit and determine if this is the case. In many instances, a malfunctioning control panel will be covered under warranty if your unit is still in the warranty period. Repairing the panel can be a challenge, so your HVAC technician might end up replacing your unit entirely.

For more tips, contact a company like McKinney Heating & Air Conditioning.