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Serving Staten Island's Heating and A/C needs since 1950


Short-Cycling Air Conditioner: What It Is, Why It’s Bad

air-conditioner-units-near-grassAmong the more common malfunctions that can occur with a residential air conditioning system is something called ­short-cycling. The brief definition of short-cycling is that it’s when the compressor of an air conditioner turns on and off rapidly—too rapidly to do much good and too rapidly for the good of the air conditioner.

We’re going to delve deeper into this common repair situation so you’ll have a better idea of when to call us for air conditioning service in Staten Island, NY.

The Basics of Short Cycling

The compressor is an essential part of how an air conditioner operates: it’s the component that changes the liquid refrigerant in the system into a hot, high-pressure gas that makes it travel through the system, first releasing heat and then absorbing it from indoors. The compressor doesn’t run continuously when the AC is on: the length of time it need to stay on depends on the temperature of the area its cooling and the moisture level. It can run from a few minutes to hours based on necessity.

However, if the compressor cycles on and off before completing the full cooling cycle, i.e. lowering the temperature to its set level, it is short-cycling. The length of a short-cycle isn’t set: it’s when the compressor doesn’t achieve its job of lowering temperature and humidity to the target before it shuts off. The best way to tell that it’s happening is not the length of time the compressor runs, but how often the compressor turns on and off several times in a row. This “stuttering” during an hour or so when it hasn’t happened before probably means a short-cycling AC.

Why This Is a Problem

“Well, it’s still cooling, isn’t it?” you might think. Yes, it is—but there are two huge problems from short-cycling:

  • If the compressor isn’t staying on long enough, the cooled air won’t have time to reach all the rooms. The house will have hot spots in it an generally less cool environment.
  • It causes the compressor to work much harder than it should. This leads to many issues, such as higher electrical bills, more repairs, and a shorter system life.

Why It Happens

There are quite a few reasons for short-cycling to start in an air conditioner, ranging from minor to major.

  • The air filter is clogged. Make sure to have the filter changed every 1 to 3 months during the time when the AC runs regularly.
  • The air conditioner is losing refrigerant. This is a big problem, since it will eventually cause the compressor to overheat and need to be replaced.
  • The thermostat is miscalibrated. If the thermostat is reading the wrong temperature, it may be prematurely signaling to the compressor to shut down.
  • The air conditioner is oversized. If the air conditioner has always short-cycled since it was put in, oversizing may be the cause. This is the biggest problem of all, and the only solution is to have a new central air conditioner installed. This is a good reminder of why you should only entrust HVAC installation to skilled professionals!

Bob Mims Heating & Air Conditioning: Serving Staten Island’s Heating and A/C needs since 1955.

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