But Why Does My Air Conditioner Turn Off by Itself? (10 Fixes!)

It may appear odd, but an air conditioner may, at times, turn itself off and then on, raising the house’s humidity and energy bills. But why does my air conditioner turn off by itself? You may ask!

The air conditioner turns off randomly due to an oversized unit, a faulty power cord or outlet, a wrongly-placed thermostat, a dirty filter or coils, or low refrigerant. Other issues include a clogged drain line, frosted coils, an electrical fault, or a failing component.

The failing component, in this case, could be the thermostat, compressor, or run capacitor, which an expert can help you diagnose. Interestingly, most issues are things you can fix yourself, and this troubleshooting guide will enable you to do just that.

Overall, what’s happening to your air conditioner is an HVAC term we call ‘short-cycling.’ Let’s talk more about short cycling and its effects. 

In a hurry? Below are the quick fixes to the ten issues likely to cause your AC to short-cycle.

Why The Air Conditioner Shuts Off Every Few Minutes and A Quick Troubleshooting Guide

What is an Air Conditioner Short-Cycling, and What are its Effects?

The term ‘short-cycling’ is an HVAC terminology that refers to the premature turning off of the air conditioner. Sometimes the AC turns itself on and off after a few minutes.

As far as short-cycling is concerned, it’s not a good thing when your AC short-cycles due to these effects:

• Higher humidity – Once your air conditioner starts going off by itself, the room becomes more humid, thus uncomfortable. Even worse, the excess moisture could attract mold, and you wouldn’t want that.
• Higher bills – The fact that your air conditioner turns itself on and off means it uses more energy. So, you will likely see an inflated energy bill at the end of the month.
• Short AC lifespan – Short cycling can wear down your air conditioner. The unit works hard to maintain the indoor temperature but may wear down much faster.
• Costly repairs – With the wearing down of the air conditioner comes expensive maintenance. You may need to replace one or two AC components, and that’s never cheap.

So, Why Does My Air Conditioner Turn Off by Itself, and How Do I Fix It?

As shared in the table above, there are ten reasons your air conditioner short-cycles. Let’s look at how you can troubleshoot them.

1. Oversized Unit

You should confirm that you have the right air conditioner size. If the unit is larger than the space it is supposed to cool, it may turn on and off every few minutes.

Fix

Use the table below to determine if your air conditioner matches your room’s square footage. You should replace it with the correct BTU rating if it doesn’t.

2. Faulty Power Cord or Socket

If your air conditioner is not getting enough power, it’s more likely to short-cycle. The reason for that could be a defective power cord or electric outlet.

If either is faulty, the air conditioner may turn on but not for long.

Fix

A multimeter is handy when checking if the power cord or electric outlet is faulty. Just probe the multimeter into the cable and socket separately and wait to see if they have continuity.

If any of them doesn’t show continuity, then that proves that it’s defective, and you should replace it.

3. Wrongly-Positioned Air Conditioner Thermostat

The air conditioner thermostat will likely malfunction if placed in the wrong position. That includes these places:

• Under direct sunlight
• In a hot room, such as the kitchen
• Close to air vents
• On the house’s shady side

The above locations are likely to trick the air conditioner into thinking that the room is hotter or colder than it is and may turn on and off by itself.

Fix

Choose a more centralized place to position the thermostat. That means away from air vents, direct sunlight, windows, the kitchen, and passages. Preferably, do it in the inside divider.

4. Filthy Air Filter

It’s advisable to change the air conditioner’s air filter every month. That’s because it’s likely to amass dirt and dust, which can clog it and prevent airflow.

Once there’s an airflow restriction, the evaporator coils may frost over and cause the air conditioner to overheat and short-cycle.

Fix

Consider replacing the air filter if it’s older than a month. The chances are that it’s dirt-clogged.

5. Clogged Condenser Coils

The air filter is not the only thing that could restrict airflow. Dirty condenser coils also have the same effect.

Since they are in the outside unit, they accumulate debris and dust over time. And once that happens, they struggle to exchange heat, forcing the compressor to shut down prematurely.

Fix

Inspect the condenser coils in the outside unit for dirt clogging and clean them. Consider using a condenser cleaning brush.

6. Insufficient Refrigerant

If the refrigerant leaks, it cannot cool the air conditioner. The AC is even more likely to overheat once it does so; it will switch on and off.

Fix

Check for these signs to determine if the refrigerant/liquid coolant is leaking:

• A noisy refrigerant pipe
• Warm air coming from the air vents
• Higher energy bills

Once you confirm the signs, contact an HVAC professional to check and refill the liquid coolant.

7. Clogged Condensate/Drain Line

Sometimes the condensate line clogs by debris, which traps moisture in the drain pan. The effect is that the air conditioner may turn on and off randomly.

Fix

Check the condensate line for clogging; if it’s blocked, pour distilled vinegar into it and wait for 30 minutes. Then flush hot water after it to unclog the drain pipe fully.

8. Iced-Over Evaporator Coils

Due to poor airflow, ice builds over the evaporator coils over time and blocks them. Unfortunately, the coils short-circuit when they block.

Fix

Start by changing the air filter, as they could be the reason the evaporator coils are icing over. But if that doesn’t work or the air filter was recently changed, contact an HVAC professional.

9. Air Conditioner Turns Off After 30 Seconds Due to an Electrical Fault

Sometimes the issue is faulty wiring or the circuit board causing the short cycling. If there is an issue with the wires (either loose or damaged) or the circuit board (most likely burnt), the air conditioner will short-cycle.

Fix

Contact a qualified local electrician to help you fix the electrical fault.

10. Failing Air Conditioner Component

Lastly, your air conditioner could turn off by itself because of a faulty thermostat, compressor, or timer. If the thermostat is defective, it cannot read the correct temperature and will turn the air conditioner on and off at the wrong time.

Meanwhile, a defective compressor will overheat and shut down the air conditioner when it does, and the same goes for a malfunctioning run capacitor.

Fix

Have an expert check the three components for fault and replace the defective one.

Split System Air Conditioner Keeps Turning Off

Your slit system air conditioner keeps turning off because of one of these issues:

• It’s oversized (has a bigger capacity than what your room needs)
• Dirty air filter (which restricts airflow)
• Dirty condenser coils (which cause the AC to short-cycle)
• Refrigerant leakage
• Electrical fault
• Iced-over evaporator coils

People Also Ask

1. But Why Does My Window Air Conditioner Turn Off by Itself?

Your window air conditioner keeps turning off because it’s too big for the space (oversized), its thermostat is wrongly positioned (near a drain line or in an extra hot room), or the air filter or condenser coils are filthy.

But still, the issue could be the power plug or electric outlet that is defective, thus disrupting its power supply, or a faulty compressor, capacitor, or thermostat.

2. How Do I Fix My AC That Keeps Turning Off?

Here are the essential tips for fixing an AC that keeps turning off:

• Replace the power cord or electric outlet if any of them is faulty
• Replace the air filter if it’s dirt-clogged (most likely older than one month)
• Clean the condenser coils if they are dirty
• Unclog the condensate drain pipe by running hot water if it’s clogged
• Position the thermostat at a more central position, away from direct sunshine and air vents
• Have an expert check the compressor, run capacitor, and thermostat for fault

3. Why Does My AC Turns Itself On and Off?

Your AC keeps turning on and off by itself because the thermostat is wrongly-positioned or malfunctioning, the air filter is filthy, the compressor is overheating, or there’s an electrical fault. But still, the air conditioner could be oversized, thus unable to cool your space.   

In Conclusion, Why Does My Air Conditioner Turn Off by Itself?

Generally, your air conditioner is turning off by itself because it’s oversized, the power cord or outlet doesn’t is faulty, the thermostat is wrongly-positioned, or the air filter or coils are filthy.

Also, consider having insufficient refrigerant, a clogged drain line, iced-over evaporator coils, an electrical fault, or a defective compressor, thermostat, or run capacitor.

Also Read:

• Why Your AC Won’t Cool Past 75 Degrees
• Why Your AC Won’t Cool Below 80 Degrees
• Amana Air Conditioner Troubleshooting Guide
• Chigo AC Troubleshooting Guide
• Why Your Rheem Ac Won’t Cool
• Troubleshooting a Rheem Air Conditioner