Why Won’t My AC Stay On?

The process of an AC shutting down and turning back on constantly is known as short cycling. Although this is a common occurrence within AC Units, it is not good for the lifespan of your AC. Short cycling occurs when the usual 10-minute cooling periods are greatly shortened. The shorter periods cause the compressor to turn on and off much more often than it should.

An example of this problem is as follows:

  1. Your thermostat is set to 72 degrees Fahrenheit. 
  2. AC begins to start up and cold air blows into the household.
  3. AC Suddenly stops the process after only 30 seconds-5 minutes.

This is bad for the system because it is constantly trying to reach the desired temperature without ever getting to it and maintaining it. This would be like constantly starting your car then shutting it off every minute or so. While it may be able to handle it for a while, it is not adding any benefit and will cause even more problems the longer it persists. 

Why does this happen?

There are a few different underlying causes of short cycling. The most common cause can be due to low refrigerant which can also cause ice build up and other problems within the system. Another cause could be using an oversized air conditioning system or the low-pressure control switch. This switch turns off the compressor if the amount of refrigerant is below the desired point for the system. Even if there is enough refrigerant, an old low-pressure control switch can fail causing the compressor to shut off prematurely. Many other parts of the unit can be negatively affected by this older switch. 

How can I fix this?

Short cycling is a big issue regarding cost, efficiency and health of the unit. There are a few steps one could take at home to find the underlying cause. However, consistent maintenance of the unit by a trained professional is the best way to prevent any of these problems from occurring.

If it is too late for preventative maintenance, here are a few steps to fix short cycling or at least find out why it is happening:

The initial step is to check on the filters within the AC. Many problems can be caused by clogged air filters, and it is a good idea to clean them even if it is not the root of this specific problem. 

The easiest step is to check the placement of the thermostat. If placed near the return air register or somewhere far from the central location of your home, it may get confused and produce the wrong readings. 

The above steps can be done easily at home. If short cycling still occurs, a professional will have to help with the next steps to find a solution. 

Refrigerant levels can be checked and refilled if necessary. They can look for leaks at the same time to help prevent any refrigerant loss in the future.  

Most cases of short cycling will be fixed after these steps are completed. On the off chance it is still causing problems, the low-pressure control switch should be replaced by a professional. 

After all this, the compressor may have to be replaced. Our HVAC professionals can check for each of these problems during the visit and make it easy for the customer. AC Tune Ups are recommended twice a year to avoid any problems such as short cycling. 

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