Why Does My AC Keep Turning On and Off Every Few Seconds?

With average highs of 85 degrees, it can be tough to stay cool in Franklin during the summer. It’s even harder when your AC unit is turning on and off and not properly cooling your home. We’ll explore common causes of AC short cycling, troubleshooting tips, and when to call a pro for AC repairs.

AC Short Cycling: What It Is and Why It’s a Problem

When your air conditioner is working properly, it naturally cycles between blowing cool air and resting the system. This cycle typically features about 10 minutes of active time, followed by 10 minutes of rest. The rest time may be longer on cooler days or slightly shorter in hot weather. 

When your AC has a problem, this cycle gets disrupted — the system turns rapidly on and off in a process called short cycling. The length of the short cycle can vary, but in most cases, any cycle shorter than 10 minutes is considered a potential problem. 

Why is AC short cycling an issue?

Short cycling is a problem because it reduces cooling efficiency and increases wear and tear on your air conditioning system. During a cooling cycle, your AC compressor circulates refrigerant through the system to cool the air. During short cycling, the compressor turns on and off rapidly, preventing the refrigerant from cycling through the full system. This rapid on and off also stresses the system, increasing the risk of a breakdown. Professional AC maintenance is the best way to avoid AC short cycling and prolong the life of your air conditioning system.

Common Causes of AC Turning On and Off Frequently

A wide variety of issues can cause AC short cycling. The following problems are some common reasons for short cycling:

Thermostat issues

The thermostat is the key signaling component that tells your AC when to turn on and off. A faulty thermostat may tell the AC the right temperature has been reached, causing it to shut off too soon. 

A number of thermostat problems can cause short cycling, including a miscalibrated thermostat or low batteries. Another common problem is a poorly located thermostat. For example, a thermostat placed directly in front of an AC vent may cool off rapidly compared to the rest of your home, signaling your AC to turn off early. 

Clogged or dirty air filter

Clogged air filters are one of the most common causes of air conditioner problems. When AC filters are dirty, it becomes difficult for air to flow freely through the system. This can lead to the air conditioner overheating and detecting a higher temperature level than what is actually in your home.

When clogged filters lead to higher temperature readings, your AC may turn on more than it should. However, as air can’t flow properly, it will then shut off quickly to allow the system to cool. This can lead to short cycling. 

Energy Star recommends cleaning and changing your AC filters at least once a month and changing them at least once every three months (or as directed by the manufacturer).

Refrigerant problems

Refrigerants are the chemicals inside your AC that facilitate the heat transfer process. They absorb heat from your indoor air and move it outside, cooling your home. 

There is a set level of refrigerant inside your AC, which shouldn’t change. However, a leak may lead to low refrigerant levels, making it more difficult for your AC to transfer heat. This can cause your air conditioner to overheat as it works harder to cool your home, leading to short cycling. Low refrigerant can also lead to other issues, such as your AC running but not cooling.

Oversized AC system

It’s important to have the right size of air conditioner for your home. A unit that’s too small will struggle to cool your home, which can lead to the system overheating and breaking down. 

A unit that’s too large will cool your home too quickly, prompting the system to shut off early. Not only can an oversized AC system cause short cycling, but it will also use an unnecessary amount of energy and drive up your utility bills. 

If your home’s AC is the wrong size, the best solution is usually a new system. While replacing your AC is an investment, it can save you a significant amount in utility costs in the long run.

Electrical issues

The capacitor is an important electrical component inside your AC that helps direct power to the compressor motor. If there’s an issue with the capacitor, the compressor may struggle to move refrigerant through your AC to cool your home. Electrical issues can often be difficult to diagnose yourself, since these components tend to be located deep inside the AC. If you suspect an electrical problem, it’s best to call an HVAC pro.

How to Fix Frequent AC Cycling — Troubleshooting Tips

The following troubleshooting tips can help you diagnose the cause of AC short cycling:

• Step one: Check the thermostat. Make sure it has fresh batteries and is set to the correct temperature. Avoid placing it near windows, vents, or direct sunlight, as this can cause inaccurate readings.
• Step two: Clean or change the air filters. If your filters are dirty or over three months old, replace them. You may need to change them more often during heavy use, if you have pets, or live in a dusty area.
• Step three: Visually inspect the unit. Look for signs like ice buildup, excess condensation, or liquid pooling around your indoor or outdoor AC units.
• Safety note: If you see ice or fluids, don’t touch them. These could signal a refrigerant leak, which can be harmful. Stick to visual checks and call a professional if needed.

When to Call for AC Repair

If your AC keeps turning on and off every few seconds and you’re not sure of the cause, it’s likely time to call for professional support.

You suspect a refrigerant problem

Refrigerants are an essential cooling component of your AC and aren’t dangerous when they stay inside the system. However, if refrigerants leak out in their liquid or gaseous form, they pose a health risk. Common signs of a refrigerant leak include a sweet, chemical smell and liquids on or near your AC. If you notice any of these problems, turn off your AC, evacuate the home, and call a pro immediately for emergency AC repairs. 

You’re not sure what the issue is

If you’ve checked the thermostats and air filters and you’re not sure what’s wrong, calling a pro is the best way to get a quick and accurate diagnosis. A professional HVAC technician can solve electrical issues and broken components and help you choose a new AC if your current system is the wrong size for your home.

Call Dugan Air for AC Short Cycling in Johnson County, IN

Find a reliable solution for AC short cycling with support from Dugan Air. Our licensed pros deliver expert advice and professional repairs for all kinds of AC problems, from short cycling and breakdowns to choosing a new home cooling system. Contact us today for qualified HVAC repairs, fair rates, and personal customer service.