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Why Does My Air Conditioner Keep Shutting Off?

John Turpin is our resident home service repair expert here at Service Direct. He’s got the knowledge and experience to help homeowners like you make sense of most home repair issues. And with Service Direct, we connect you with top-tier service professionals to help with any repairs needed.

Find Out Why Your AC Keeps Turning Off

It’s happened more than a few times already and you’re racking your brain wondering, “Why does my air conditioner keep turning off?” There’s a good chance something’s wrong with it, but don’t call an HVAC expert yet. It’s possible the AC keeps turning off for an entirely simple reason, one that you can address yourself.

We know how frustrating it can be when your air conditioner keeps shutting off, especially during hot summer days. If you’re experiencing this issue, it’s essential to understand the possible causes and find a solution to your dilemma. In this article, we’ll explore some common reasons why an air conditioner may repeatedly shut down and provide solutions along the way.

Air Conditioning Shutting Off
Check out the list below for the most common causes your air conditioning is shutting off.

Common Reasons Your Air Conditioner Keeps Shutting Off

Do you want to know why your AC turned off by itself and won’t turn on? Or why it keeps turning off after 30 seconds? Check out some of the possible reasons below!

Thermostat Issues

One possible cause of your air conditioner shutting off is a faulty thermostat. Check if it is set to the desired temperature and mode. Ensure that it is properly calibrated and not affected by heat sources or direct sunlight. If you suspect an issue with the thermostat, consider replacing it or consulting a professional for assistance.

Clogged Air Filters

Blocked or dirty air filters can restrict airflow, leading to reduced cooling efficiency and causing the air conditioner to shut off. Check the air filters and clean or replace them if necessary. Regularly maintaining clean filters improves the airflow and prevents the system from overheating.


Air conditioners have safety mechanisms that shut off the system if it becomes overheated. Several factors can contribute to overheating, such as blocked vents, a dirty condenser coil, or a malfunctioning fan. Ensure that the condenser coil is clean, the vents are unobstructed, and the fan is functioning correctly. Regular maintenance and cleaning can help prevent overheating issues.

Faulty Capacitor or Relay

The capacitor and relay are electrical components that control the motor and compressor of the air conditioner. If either of these components is faulty or worn out, it can cause the system to shut off intermittently. For this issue, you should contact a trained technician. They can diagnose and replace these components if necessary.

Our resident home repair guru, John Turpin, explores a list of common reasons why your air conditioning is shutting off, including some advice on what to do.

Inadequate Airflow

Insufficient airflow can trigger the AC’s safety mechanism, causing it to shut off. Check for any obstructions or blockages in the air vents, fan, or ductwork. Ensure that furniture or other objects don’t block the events and impede airflow. Improving ventilation and air circulation within the space should help resolve this issue and ideally fix your AC that keeps shutting off.

Electrical Problems

One possible reason for an air conditioner shutting off all the time is it might have electrical issues. It could be due to a tripped circuit breaker or a loose electrical connection. Rule them out by checking the circuit breaker panel to ensure that the breaker for the AC isn’t tripped. Also, inspect the electrical connections and tighten any loose wires. If you’re unsure or uncomfortable working with electrical components, consult a professional technician.

Low Refrigerant Levels

Low refrigerant levels can cause the air conditioner to shut off as a protective measure. The refrigerant is responsible for absorbing heat and cooling the air. If it leaks or has insufficient levels, the system may shut down. If you suspect this is the issue with your AC, contact a professional HVAC technician to repair any leaks or recharge the system as needed.

Air Conditioning Fault Diagnosis
An HVAC expert has the tools and training to diagnose and repair faulty air conditioning units.

Malfunctioning Fan Motor

The fan motor plays a crucial role in circulating air throughout the system. If it’s defective or experiencing issues, such as electrical problems or overheating, it can cause the AC to shut off. For this issue, it’s best to reach out to a professional technician to diagnose and repair or replace the faulty fan motor.

Dirty Evaporator Coil

The evaporator coil is responsible for cooling the air in the air conditioning system. Over time, the coil can accumulate dirt and debris, affecting its efficiency and causing the air conditioner to shut off. Regular cleaning of the evaporator coil can help prevent this issue. However, it’s recommended to seek professional assistance for coil cleaning to avoid damage.

System Size and Load

An air conditioner that is undersized for the space it’s cooling may struggle with meeting the cooling demands. It could be why your air conditioner turns off after 30 seconds. Additionally, the air conditioner may shut off when the heat load in the room is excessive due to factors like heat-generating appliances or high occupancy. The AC does this to prevent damage. In such cases, consider upgrading to a larger capacity unit or implementing energy-saving measures that can help alleviate the issue.

Short Cycling

Short cycling refers to when the air conditioner turns on and off frequently in short intervals. This can be caused by various factors, including a malfunctioning thermostat, oversized AC, blocked vents, or incorrect refrigerant charge. Short cycling not only disrupts cooling efficiency but also puts unnecessary strain on the system, possibly leading to further problems.

Sensor Problems

Some air conditioners are equipped with temperature sensors that detect the ambient temperature and adjust the cooling accordingly. If the sensor is malfunctioning or incorrectly calibrated, it can cause the AC to turn off prematurely. In this case, just ensure that the sensor is clean, properly positioned, and functioning correctly.

Aging or Deteriorating System

Over time, air conditioning systems can experience wear and tear, leading to various issues that cause frequent shutdowns. Aging components, worn-out electrical connections, or general system deterioration can contribute to the problem. If your system is old or showing signs of significant wear, it may be more cost-effective to consider replacing it with a new, energy-efficient unit.

Faulty Compressor

The compressor is the heart of the air conditioning system. It’s responsible for compressing the refrigerant and facilitating heat transfer. If it’s faulty or has some issues, like a motor failure or electrical problems, it can lead to the air conditioner shutting off. Repairing or replacing the faulty compressor is usually the solution, but it requires professional expertise.

Air Conditioning Repair Contractor
Some issues are more common than others, so reach out to a pro when in doubt of what to do.

Air Conditioning Shutting Off FAQs

How long should an air conditioner’s cycle last?

On average, an air conditioner cycle typically lasts around 15 to 20 minutes to cool down a room. But shorter or longer cycles can occur based on the thermostat settings, outdoor temperature, and the AC unit’s efficiency. It’s important to note that frequent short cycles (less than 10 minutes) or excessively long cycles (more than 30 minutes) can indicate potential issues with the AC system. This means that your AC may need professional attention for diagnosis and adjustment.

Is it okay for the air conditioner to run all day?

According to HVAC experts, it’s perfectly okay for your air conditioner to run all day. But this makes it even more important to perform regular maintenance. This is because using the AC for 24 hours means it has more wear and tear on its system. Ultimately, it’s your decision to run your AC all day based on your comfort needs, energy efficiency goals, and environmental considerations. Try to find a balance that suits your preferences while being mindful of your energy consumption and the associated costs.

When should I contact a professional for help?

If basic troubleshooting steps like cleaning the air filter and checking the thermostat don’t resolve the issue, it’s best to contact a professional HVAC technician. Professionals have the expertise and experience to diagnose and fix more complex problems related to the electrical system, components, and refrigerant levels of the AC.

Hire a Local HVAC Technician

Remember, while some issues can be addressed by homeowners, it’s important to recognize when you need professional assistance. HVAC technicians are certified and experienced at diagnosing complex problems and performing repairs. Contact a pro if you’re uncertain or unable to resolve the issue yourself.

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