Why does my AC work for a few hours then stops?

Author: Veronica Harris  |  Last update: Wednesday, April 9, 2025

Some common reasons your air conditioner may not be cooling include: Clogged filter. Clogged drain. Condensate airflow switch.

Why does my AC work for a little while then stops?

Electrical problems are a common cause of short cycling. This may indicate that there is an issue with the electrical supply line or the capacitor could be broken or failing. This can be caused by the thermostat, electrical connections in the system, or the circuit boards.

Why does my AC trip the breaker after a few hours?

If your air conditioner is tripping the breaker, there can be a range of issues behind it, such as a dirty air filter, dirty condenser coils, fan damage in the outdoor unit, a faulty compressor, damaged or loose electrical wiring, or a bad circuit breaker.

Why does my AC stop working then starts again?

Dirty air filters restrict air flow, which can cause your AC unit to start and stop again. Check your air filter and replace it if it's dirty.

Why does my AC kick on then shut off?

If your AC unit is turning on and then off right away, there are several possible causes. These include thermostat problems, refrigerant leaks, oversized AC units, and dirty air filters. With the exception of a dirty air filter, most of these issues should be addressed by a qualified HVAC technician.

9 Reasons Why Your Air Conditioner Starts Then Stops Quickly

How to fix AC short cycling?

Fortunately, there are plenty of ways you can put an end to your air conditioner's short-cycling issues:
  1. Check your air filter. ...
  2. Check your thermostat placement. ...
  3. Check your air conditioner's refrigerant levels. ...
  4. Replace the low-pressure control switch. ...
  5. Check the compressor.

How to unclog an AC drain?

To unclog an AC drain line, turn off the power to the unit. Locate the drain line and use a wet/dry vacuum to suck out the clog. Flush the line with water using a garden hose or cup of water. Check and clean the drain pan under the indoor unit.

Why does my AC stop cooling after a few hours?

First, check your filters and coils for dirt and debris that may be impeding airflow. Once you've cleaned the filters and coils, run the air conditioner with just the fan so that the ice accumulation can melt off. If the AC still doesn't blow cold air, it could be that refrigerant levels are too low.

What is the first thing to check when the AC stops working?

Check these issues when the unit won't kick on: Check the thermostat and adjust the settings if it isn't set to Cool and an appropriate temperature setting to call for cooling. Examine the house circuit breakers for the AC unit and reset any tripped breakers. Check the air filter and replace the filter if it's dirty.

Why does my car AC work for an hour then stops?

AC Works Intermittently: When the air goes from cool to warm to cool again, you're experiencing intermittent problems. This is often due to a clog in the system, a failed compressor or compressor clutch, a faulty condenser fan, a clog in the system, or the actuator directing airflow has failed.

Will low freon trip breaker?

If the AC refrigerant charge is low, your air conditioner will work beyond its normal limits to try to keep the thermostat happy. This can be the reason the A/C is tripping the circuit breaker, and it also indicates that your system has a refrigerant leak that needs attention.

How do I know if my AC breaker is bad?

How to Tell if a Circuit Breaker Is Bad
  1. It's Frequently Tripping.
  2. You Notice Visible Damage.
  3. It Won't Stay Reset.
  4. It's Hot to Touch.
  5. You Notice a Burning Smell.
  6. You Experienced a Recent Electrical Surge.
  7. Your Breaker Is Old and Worn Out.
  8. You Have an Overloaded Circuit.

How much does a compressor cost for an air conditioner?

On average, AC compressor costs range from $800 to $2,300, with most folks paying $1,200 for a new one. However, your price will vary depending on factors like the size and brand of your compressor. Before you schedule your replacement, read on to learn about all AC compressor cost factors.

How to tell if AC refrigerant is low?

Here are some of the symptoms of an air conditioner with low refrigerant:
  1. Takes Your AC a Long Time to Cool Off. ...
  2. Indoor Air Not Blowing Cool Enough. ...
  3. Frost or Ice on Copper Lines. ...
  4. Water Pooling Around the Furnace. ...
  5. Listen for a Hissing or Bubbling Noise. ...
  6. Short Cycling. ...
  7. Electric Bills Higher.

What does short cycling mean?

In the heating, ventilation, and air conditioning (HVAC) business, short cycling is a phrase used to describe when a heater or air conditioner cycles on and off too frequently. It signifies a problem in your heating system's proper functioning and efficiency, in which it is not completing its heating processes.

Why does my AC keep tripping the breaker?

So what is causing this issue in the first place if the AC runs for a bit without much of an issue? There are a few causes: a dirty air filter, a dirty outside unit, an issue with the circuit breaker, a shorted motor, a compressor that is having a hard time starting, or a compressor that is grounded.

Why did my AC stop working then start again?

Obstructions. Some homeowners ask, “Why does my AC stop and start again with new components?” Dirt and debris in your condenser coils and air ducts can stress your AC unit. Eventually, your appliance may overheat and shut down. Schedule routine vent cleanings to prevent his problem from occurring.

Should I turn off AC if it's not cooling?

Yes, you should turn off your AC if it's not cooling.

How long do air conditioners last?

It's important to be aware of how long air conditioners last, so you don't get the unwelcome surprise of a broken air conditioner in the peak of the summer heat. In general, air conditioners that are properly maintained can last 15 to 20 years.

How do I know if my evaporator coil needs cleaning?

Here Are Five Telltale Signs That Your AC Coils Are Dirty And Need to be Cleaned
  1. Your electricity bill has been going up. ...
  2. Your unit seems to be running longer for no reason. ...
  3. Your home doesn't feel as cool as it should be. ...
  4. The Coil is Covered in Frost While Running. ...
  5. Higher Indoor Humidity.

How do I reset my central AC not blowing cold air?

Use these tips to reset an air conditioner using the reset button:
  1. Turn your thermostat to the “off” setting.
  2. Turn off the circuit breaker that powers your AC.
  3. Press and hold the reset button for three to five seconds.
  4. Restore power to your AC by flicking the circuit breaker back on.

Why does my AC cool then stop?

Dirty or Frozen Coils

If the condenser coil is dirty, your AC can't complete the cooling process. It can cause the unit to malfunction and shut down whenever you turn it on. To avoid this, clean the condenser coil regularly. You can use a coil brush to clear debris and a fin comb to realign the coil fins.

How to tell if an AC drain is clogged?

What Are the Symptoms of a Clogged AC Drain Line?
  1. Standing water near your air conditioner's condenser unit.
  2. A moldy smell around the drain or from your system's vents and registers.
  3. Water damage around the unit.
  4. An air conditioner that shuts off unexpectedly.
  5. An HVAC system that is not effectively cooling your home.

How much does it cost to unclog an AC drain line?

Flush Condensate Drain Line

The repair cost to have the drain line flushed runs between $75 to $250.

How often should I clean my AC drain line?

You should flush your AC drain line once every three months to keep it clear of debris and buildup. Keeping your AC drain line clean prevents clogs, backups, mold growth, and extra wear on your AC unit.

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