Why Does Your AC Keep Turning Off? Top Causes & Fixes
June 4, 2025
Categories: Air Conditioning
When your air conditioner is working properly, it runs in cycles, with a typical cooling cycle lasting between 15 and 20 minutes, depending on your thermostat setting and indoor temperature. During each cycle, the system pulls warm air from your home, cools it down using refrigerant and an evaporator coil, and then distributes that cooled air throughout your living space. Once your home reaches the desired temperature, the system shuts off until the next cycle begins.
However, it’s important to note that if your AC keeps turning off shortly after it starts — sometimes within minutes — this frequent on-and-off cycling, also known as “short cycling,” is a sign of a larger issue that needs immediate attention. For example, you may have a faulty thermostat, low refrigerant levels, or a failing capacitor, all of which require the expertise of an AC repair technician.
To help you understand how you can reclaim your home’s comfort this summer, let’s explore the top causes and fixes for an air conditioner that keeps shutting down unexpectedly.
1. Thermostat Problems
One of the most likely reasons your AC keeps turning off is an issue with the thermostat. If this control does not accurately read the temperature, it will signal the system to shut off prematurely. A faulty thermostat could be caused by:
- Dead or low batteries (in battery-operated models)
- Placement too close to a heat source (like a window or lamp)
- Wiring problems or internal malfunctions
To fix the issue, start by checking and replacing the thermostat batteries. If the problem isn’t resolved, ensure that the thermostat is mounted in a location free from direct sunlight or heat. If none of these are the issue, it might be time to have a technician recalibrate or replace the thermostat.
2. Dirty Air Filters
Air filters that haven’t been replaced in a while can get clogged with dust, pet hair, and other airborne debris. When this happens, airflow is restricted, causing the system to overheat. Many modern HVAC systems are designed to shut down automatically to prevent damage when overheating is detected.
The good news is that checking and replacing an old air filter is easy. Give the filter a once-over. If it’s dirty or hasn’t been changed in three months, go ahead and replace it. This simple but essential maintenance task keeps your AC running smoothly.
3. Refrigerant Leaks
Refrigerant is the lifeblood of your air conditioning system. It absorbs heat from inside your home and releases it outside. If there’s a leak in your refrigerant lines, the system may not have enough refrigerant to complete a cooling cycle. This can cause pressure imbalances, leading the AC to shut down shortly after it starts. You may also notice signs like ice forming on the evaporator coils or strange hissing noises.
It’s important to note that refrigerant leaks need to be diagnosed and fixed by a licensed HVAC technician. They can safely repair the leak and recharge your system with the correct amount of refrigerant to prevent more costly repairs in the future.
4. Frozen Evaporator Coils
Evaporator coils are responsible for absorbing heat from the air in your home. When airflow over the coils is restricted, or when refrigerant levels are too low, the temperature inside the unit can drop too much, causing moisture in the air to freeze on the coils. Once frozen, the coils can no longer absorb heat efficiently. As a result, your system may shut down to prevent further damage or simply stop working altogether.
Turn off the air conditioner and allow the coils to thaw completely. This could take several hours, so be patient. After thawing, check and replace the air filter if it’s dirty. If the coils continue to freeze or the system keeps short cycling, call a technician to perform a more thorough inspection.
5. Electrical Issues or Faulty Capacitors
Your air conditioner relies on a network of electrical components to function properly. For example, capacitors, relays, and wiring all work together to help the system start up and continue running. If any of these components fail, they can cause the system to shut off unexpectedly.
Due to the complexity and danger associated with electrical components, it’s best to leave this work to a certified HVAC technician. A professional can safely test and replace faulty capacitors, repair wiring, and ensure that your system is running reliably. They can also recommend when a new AC installation is necessary.
6. Oversized AC Unit
It may seem logical that a larger AC unit would cool your home more effectively, but in reality, an oversized unit often causes more problems than it solves. When an air conditioner is too large for the space it’s supposed to cool, it lowers the temperature too quickly. This rapid cooling causes the system to cycle on and off more frequently than it should.
If your system is oversized, the best long-term solution is to replace it with one that is correctly sized for your home. A professional HVAC contractor can perform a load calculation based on your home’s square footage, insulation, windows, and other factors to determine the correct system size for optimal performance.
7. Clogged Condensate Drain Line
During operation, your air conditioner removes moisture from the air and drains it through a condensate line. Over time, algae, mold, or dirt can build up in this line, causing a blockage. When this happens, the water can back up into the system. Many modern units include a safety float switch that shuts the system down to prevent water damage.
Inspect the condensate line for visible signs of blockage. You may be able to use a wet/dry vacuum to clear it out. If you’re not comfortable doing this or the problem recurs, call a professional for a thorough cleaning and inspection to prevent future clogs.
8. Faulty Compressor
The compressor is often referred to as the heart of your air conditioning system because it pumps refrigerant through the system and maintains the necessary pressure levels. When the compressor begins to fail, the system may struggle to run for more than a few minutes. This leads to short cycling and insufficient cooling throughout your home.
A failing compressor is a serious issue that typically requires professional diagnosis and repair. In some cases, compressor replacement may be more cost-effective than continual repairs, especially if your unit is older.
Call Martinov Home Solutions to Resolve Short Cycling Issues
As you can see, there are many reasons your air conditioner might be shutting off unexpectedly, and many of them are signs that a bigger issue is brewing. Since ignoring the problem can only lead to increased energy bills, costly repairs, and even premature system failure, make sure you seek help from a qualified HVAC technician at Martinov Home Solutions. We handle everything from thermostat calibration and air filter replacement to electrical troubleshooting and compressor repair. No matter what’s causing your AC to short cycle, we’ll deliver fast, effective solutions that restore your comfort.
Contact Martinov Home Solutions today to schedule your central air or ductless mini-split repair and enjoy consistent, efficient performance from your HVAC system all summer long. You will also quickly see why we’re the right company for your air conditioning repair.