8 Reasons Why Your AC is Short Cycling


Your home’s air conditioning system is built to detect an increase in temperature and initiate a cooling process. When your home begins to heat up, the thermostat in your AC picks this up and sends this message to your AC unit, which kicks in to cool your room. However, if the air conditioning system stops before it completely cools your home, it shows that there is a problem with your AC that needs to be fixed. This type of problem is what is known as short cycling.

When Does AC Short Cycling Occur

Typically, an AC cycle lasts about 20 minutes. However, your air conditioning system can have short cycles known as a short cycle. During short cycling, your AC turns on and off in brief bursts without cooling or heating your home appropriately. In short, cycling an AC becomes less efficient, thus increasing your home’s energy bills.

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It also causes wear and tears on your air conditioning unit. In turn, the comfort of your home will be compromised. You need to troubleshoot an AC that short cycles quickly to counter the possibility of more damage to occur. The first thing to do when troubleshooting is to identify the potential causes of the short circuit.

Low Level of Refrigerant

If the refrigerant level in your AC is low, the unit will not be able to cool your home appropriately. Therefore, this will put a lot of stress on several components of your AC, causing them to work harder. In turn, the air conditioning unit will suffer wear and tear and operate irregularly.

Iced or Dirty Evaporator Coil

Dirty evaporator coils are a common problem for homeowners who do not carry out routine preventive AC maintenance activities on their appliances; that is, the air conditioner. Your AC’s evaporator coil gets hot air out of your house. When your air conditioning unit cannot take the hot air out effectively, it will compensate for this failure by working very hard to accomplish the task. This might cause overheating in your air conditioner and, in extreme cases, shutting off.

Oversized Air Conditioner

An oversized air conditioner is not good for your home. You need to get an air conditioner that is neither too big nor too small for your space. If the AC is too big, it will cool your home quickly, then turn off. When this happens too often, your home’s energy bill will increase. You will also request more services from your HVAC specialist. Your AC may also cause uneven cooling in your home, which can be uncomfortable.

Dirty or Clogged Air Filter

When you fail to replace your AC’s air filters regularly, it may accumulate dirt. This build-up of dirt and debris will force your air conditioning unit to work harder than it should. When it becomes too clogged with dust, dirt, and many more microscopic particles, the AC will naturally work more to account for some of its lost functions due to clogging. Therefore, the parts that operate your AC’s compressor (view on Amazon) and blower become too stressed. These parts can become overheated, resulting in short cycles in your air conditioning unit. In an extreme case, your AC will completely break down and cost you a lot of money in repairs.

Now that you know the potential causes, how will you diagnose and fix the issue? Here are some of the measures that you can put in place to correct your broken AC and restore it to its normal function.

Air Conditioner Short Cycling Diagnosis

There are different types of short cycles. They include:

Air Conditioner Short Cycling in Minutes

If your AC switches off and on at short intervals, of not more than 5 minutes, the AC is most likely short cycling and should be repaired immediately. If the AC switches on and then off at short intervals of not more than 10 minutes, there is a high likelihood that it is short cycling. In both of these cases, you need to call an HVAC specialist form your locality to come and fix the air conditioning unit.

Unsteady On-Off Cycling of Your AC

An AC that short cycles can also produce sounds that indicate it is running at irregular intervals during a specified period. This happens despite having the same indoor thermostat setting throughout the given period. Your AC’s condenser/compressor unit is the heat pump equipment or the air conditioner, which is situated outside.

Fortunately, some of the causes of air conditioner short cycles are easy to fix and are not very expensive. Some causes, such as dust-clogging your AC’s thermostat or dirty air filters, can be sorted out by you. Other complex issues, such as short cycling issues, need a skilled person to work on it, like an HVAC technician.

AC Short Cycling in Seconds

When the short cycles happen in seconds – the AC condenser/compressor turns on and off in a few seconds – then the whole air conditioning unit is under the serious problem that needs to be fixed immediately. Shut off your AC unit and contact your HVAC Company or technician for solutions.

Normal Air Conditioner On-Off Cycling Times

When you have the right-sized air conditioning unit, the unit will work to cool your home at approximately half-time on an average day. It will not work more than 50% of its cooling capacity. Even though the real on time of your AC will differ for many other reasons, including the cooling coil cleanliness and the fan speed of indoor air handler, you will hear the running sound of your AC for approximately 10 minutes. It will turn off and remain off for ten minutes, too, before turning on once more. This cycle could also be a 20-minute cycle.

If your heat pump or AC runs for twenty or ten minutes or even longer, then shuts off for the same amount of time before turning on again, then your AC is not short cycling, but operating as it should. Short cycles occur when there are irregular intervals in the cycle.

In hot weather, the air conditioning unit may run almost constantly. Check the temperature of air coming from your AC. If the air is cooler, then your AC unit is working as expected.

Reasons Why Your Home Air Conditioner Compressor Short Cycles Rapidly

Short cycling is abnormal. When it happens in very short intervals, it is alarming. What causes the rapid short cycling of your home’s air conditioning unit?

  • AC Coil Icing

The cooling or evaporator coil is iced over because of improper charge or the refrigerant or reduced airflow due to a dirty filter or dirt. Inspect the air handler to find out if the coil in there is dirt or ice blocking the handler.

When your air conditioner’s power source is cut and air if not flowing within your unit, the air can flow through your AC because the coil clears, ice melts, and your air conditioning system will be restored to its normal working condition. However, if the coil of your AC is frost or ice blocked again, it will not cool your home as expected.

Examine your AC’s cooling coil within the air handler of your air conditioner, if you can spot it. In some air conditioners, you cannot be able to see the coil directly until you remove the access panel. The cooling coil can be located on the end outlet of your AC’s air handler. For a vertical unit, it can be seen on top of the blower fan assembly.

If you observe a thick frost or ice covering your Ac’s cooling coil, it is likely that the ice has blocked the coil. Turn off your AC unit to melt the ice. Re-start your AC later on. However, your AC will have to be checked by an HVAC specialist for further diagnosis and a tailored solution.

Loss of Air Conditioner Refrigerant

When refrigerant leaks from the system, you can repair the issue to stop your unit from short cycling. However, you can fix this issue temporarily by recharging your AC system as you wait for an HVAC specialist to come and fix the leak in the system. This will save you from spending a lot of money on refilling the refrigerant.

Some heat pumps and air conditioners have a low-pressure button that switches off the compressor motor in case there is insufficient refrigerant. This switch or button is installed to offer your system protection from damage. Therefore, if your thermostat sends a signal to the AC to cool, and the condenser/compressor fan responds by running, but the compressor remains off, this button/switch is broken. Call an HVAC specialist or repair company to fix the problem.

You Need to Know This About Your AC

If you’re noticing problems with your AC, you need to know what’s causing the issue and if you’ll need to get the AC repaired or replaced. Having a working AC is crucial for any home, and fixing it is just one form of home improvement, but there are many more.

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Bad refrigerant TEV, Cap Tube or Metering Device

If your AC’s thermostatic expansion valve sticks without releasing refrigerant into your AC’s cooling coil, the compressor will build dangerously high pressure on its outlet end, which is also the high side of your AC system. In some compressor units, a high-pressure cut-out switch or safety switch is installed, which turns off the compressor motor. When there is abnormally high pressure on the system, the AC’s safety control switch is tipped.

Oversized Air Conditioner

In some cases, the short compressor on-cycling was problematic since the air conditioning unit was installed in your home. If this is your reality, there is a high likelihood that your AC unit is very big, or it has a lot of BTUs for your home’s room size that is to be cooled.

If your home cools faster but has high levels of humidity, the chances are that your air conditioning unit is too big. A good-sized AC will cool your house and lower the levels of humidity of your home. You can, however, counter this issue by running your AC’s blower fan at a slower speed. You can also open your interior door to make the space being cooled larger or move your thermostat. All these measures will help mitigate this problem.

Overheating Electric Motors

Some fan motor and home compressor motors have circuitry, which turns off the motor during a thermal overload or when your air conditioning unit overheats. Your AC’s motor might be getting hot because of bad voltage or other great cycling demands from the AC’s controls, or mechanical damage, or failing bearing, or lubrication failure or any other fault in your air conditioning unit.

Some motors have advanced features that allow them to automatically reset their thermal overload switch immediately after the motor cools, which will force the motor to start running again. Some people cool the outdoor compressor by showering the unit with water from their garden hose.

These are some of the main reasons why your air conditioning unit keeps short cycling. Use the solutions provided herein to fix these issues. You should contact an HVAC specialist if need be. However, you should consider buying a new AC if your current AC is old.


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