When your air conditioner compressor stops working, you might feel the heat right away. What to do when AC compressor stops working? A common first step you can try is resetting it. This simple step can sometimes fix minor issues that caused the compressor to stop. Often, a simple power cycle or resetting the AC breaker is all that is needed. This article will walk you through how to safely perform an air conditioner breaker reset and other steps to get your cool air back.
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Grasping Your Air Conditioner System
Before you try to reset anything, let’s talk about how your AC works. Your home air conditioner has two main parts:
- The indoor unit: This is usually a furnace or air handler. It blows cool air into your house.
- The outdoor unit: This is the big box outside. It has a fan, coils, and the compressor. The compressor is like the heart of the system. It pumps the refrigerant that cools the air.
When your AC isn’t cooling, even though the indoor fan might be blowing, the problem is often with the outdoor unit, especially the compressor.
Why Your AC Compressor Might Stop
Several things can cause an AC compressor to stop working. It might just need a quick reset, or it could be a bigger problem. Knowing the possible causes helps you decide what to do.
Common Reasons for Compressor Issues
h4>Overheating or Overload
Just like any hard-working machine, your compressor can get too hot. This often happens on very hot days or if the unit is working too hard. Most compressors have a safety feature called an AC compressor overload trip. This trip turns off the compressor to stop it from getting damaged by heat. A reset can clear this trip once the compressor has cooled down.
h4>Electrical Problems
Power surges, low voltage, or wiring issues can mess with the compressor. Sometimes, this causes an AC tripped breaker fix to be needed at your electrical panel. A reset can sometimes help after a power blink.
h4>Dirty Coils
The outdoor unit has coils (metal fins) that need airflow to cool the refrigerant. If these coils are covered in dirt, dust, or leaves, the unit can’t get rid of heat well. This makes the compressor work harder, leading to overheating and tripping the overload. The AC fan might run, but the compressor stays off.
h4>Low Refrigerant
The compressor pumps refrigerant. If the system is low on refrigerant (due to a leak), the compressor can struggle and overheat. A reset won’t fix a refrigerant leak, but it might let the compressor run for a short time, giving you a clue something is wrong.
h4>Bad Capacitor
The outdoor unit has a part called a capacitor. It gives the compressor an electrical “kick-start” to get it running. If the capacitor is weak or bad, the compressor might not start, even if the fan runs. Resetting the system won’t fix a bad capacitor. This often leads to the symptom of the AC fan running but compressor not.
h4>Mechanical Failure
Sometimes, internal parts of the compressor can wear out or break. This is a serious problem that needs a professional.
When Resetting Can Help (And When It Won’t)
Resetting your AC system is like restarting your computer. It can fix small glitches or clear temporary errors, like an AC compressor overload trip caused by a short period of heavy use or a minor power issue.
Resetting Might Help If:
- The AC worked fine, then suddenly stopped cooling on a very hot day (possible overload trip).
- You recently had a power outage or flicker.
- The outdoor unit just stopped running for no clear reason, and the indoor fan is blowing.
- You want to perform a simple troubleshoot AC not cooling step.
Resetting Will NOT Help If:
- There’s a strange noise coming from the outdoor unit (grinding, buzzing).
- You smell burning.
- The outdoor unit is dirty and blocked.
- There’s ice on the coils or refrigerant lines.
- The issue is a known refrigerant leak.
- The capacitor is clearly swollen or leaking (a sign it’s bad).
- The breaker trips right away every time you reset it.
Resetting HVAC compressor is a good first step for simple issues, but it’s not a magic fix for major problems.
Safety First: Always Turn Off Power!
Working with electrical appliances, especially one as powerful as an AC unit, can be dangerous. You MUST turn off the power before you do anything near the outdoor unit or the circuit breaker.
There are typically two places to turn off power to your AC:
- The main electrical panel: This is where the circuit breakers for your whole house are located. Your AC unit should have its own dedicated breaker (or pair of breakers).
- The outdoor disconnect switch: There is usually a small box mounted on the wall near the outdoor AC unit. This box contains a pull-out handle or a switch to cut power only to the outdoor unit.
Always turn off power at BOTH locations if you plan to touch or inspect the outdoor unit. For a simple reset involving only the breaker or thermostat, turning off the breaker is enough to cut power to the whole AC system.
The Simple Steps to Reset Your AC Compressor
Resetting your AC system involves cutting power to it completely for a short time and then turning it back on. This allows the system’s control board and safety features to reset. Here are the common methods:
h4>Method 1: Resetting Using Your Thermostat (Power Cycle)
This is the easiest method and often the first one to try. It performs a basic how to power cycle AC unit action.
- Set Thermostat: Go to your indoor thermostat. Turn the system switch from “Cool” to “Off.” If your thermostat has a fan setting, set the fan to “Auto” (not “On”).
- Wait: Leave the system off at the thermostat for at least 5-10 minutes. This waiting time is important. It allows pressure in the refrigerant lines to equalize and gives any tripped safety switches time to reset, like the AC compressor overload trip.
- Turn System Back On: After waiting, go back to the thermostat. Set the fan to “Auto” and the system switch back to “Cool.”
- Set Temperature: Lower the thermostat temperature setting to a level below the current room temperature (e.g., 70°F or lower) to tell the AC to start cooling.
- Listen and Check: Wait a few minutes (5-15 minutes). Listen for the outdoor unit to start up. Feel the air coming from the vents inside to see if it’s getting cool.
If this works, great! The issue was likely a minor glitch.
h4>Method 2: Resetting the Circuit Breaker (Air Conditioner Breaker Reset)
This method cuts power more directly and is a common AC tripped breaker fix. Use this if the thermostat reset didn’t work or if you suspect the breaker tripped.
- Locate the Breaker: Find your main electrical panel. Open the door to see the rows of circuit breakers.
- Identify the AC Breaker: Look for the breaker labeled “AC,” “Air Conditioner,” “HVAC,” or similar. It’s usually a double-pole breaker (two switches connected together). The size is often 20 amps, 30 amps, or even 50 amps, depending on your unit.
- Turn the Breaker Off: If the breaker is in the “On” position, firmly push the handle all the way to the “Off” position. If the breaker is already in a middle position (tripped), push it firmly to the “Off” position first.
- Wait: Leave the breaker in the “Off” position for at least 10-15 minutes. This ensures the entire system loses power and allows components like the compressor time to cool down and safety controls to reset.
- Turn the Breaker On: After waiting, firmly push the breaker handle all the way to the “On” position.
- Set Thermostat: Go inside to your thermostat. Make sure the system is set to “Cool” and the temperature is set low enough to call for cooling.
- Listen and Check: Wait 5-15 minutes. Go outside and listen for the outdoor unit to start. Check the air inside.
h5>What if the breaker was already tripped?
If you found the breaker already in the middle (tripped) position, this means something caused it to trip. Resetting it might get the AC running, but if it trips again soon, there’s a bigger problem that needs investigating. Common reasons include the AC compressor overload trip, a short circuit, or the unit drawing too much power due to another issue.
h4>Method 3: Resetting the Outdoor Disconnect Switch (Outdoor AC Unit Reset)
This method cuts power only to the outdoor unit. It’s often used by technicians but can be part of a DIY outdoor AC unit reset if you are careful. Always turn off the breaker inside first for safety before touching this box.
- Turn Off Breaker: Go to your main electrical panel and turn off the AC breaker as described in Method 2. DO NOT SKIP THIS STEP.
- Find Disconnect Switch: Locate the small box on the wall near your outdoor AC unit.
- Open the Box: Open the cover of the box. There might be a pull-out block, a switch, or a lever inside.
- Cut Power:
- If it’s a pull-out block, firmly pull the block straight out. Flip it over (it usually has “On” on one side and “Off” or nothing on the other) and re-insert it with the “Off” side facing up or out, or simply leave it pulled out.
- If it’s a switch, flip it to the “Off” position.
- If it’s a lever, push or pull it to the “Off” position.
- Wait: Leave the power off at both the disconnect and the breaker for at least 10-15 minutes.
- Restore Power:
- Go back to the outdoor disconnect. Re-insert the pull-out block correctly (“On” side up/in) or flip the switch/lever back to “On.”
- Go back to the electrical panel and turn the AC breaker back to “On.”
- Set Thermostat: Go inside, set the thermostat to “Cool” and the temperature low.
- Listen and Check: Wait 5-15 minutes for the outdoor unit to start and check the air inside.
Important Note: Only use this method if you are comfortable locating and operating the outdoor disconnect switch. If unsure, stick to resetting the breaker and thermostat.
What Happens After You Reset?
After you perform the air conditioner breaker reset or thermostat power cycle, you should hear the outdoor unit fan start first, usually within a minute or two. Then, you should hear a click, and the compressor should start. The outdoor unit will get louder once the compressor is running.
Feel the larger of the two copper lines coming out of the outdoor unit. It should feel cool, and possibly wet from condensation. The smaller line might feel warm. This is a good sign the refrigerant is flowing and the compressor is working.
If the outdoor unit starts and begins blowing cold air inside, the reset likely fixed a temporary problem. If the AC unit won’t start, or the fan runs but the compressor does not (AC fan running but compressor not), you likely have a different issue.
Troubleshoot AC Not Cooling: What If Resetting Doesn’t Work?
If you followed the steps for resetting HVAC compressor and your AC unit still won’t start, or it starts but still isn’t cooling, you need to look for other causes or call a professional. Here’s a quick troubleshoot AC not cooling guide for DIY checks after a reset fails:
h4>Check the Air Filter
A dirty air filter can severely restrict airflow, causing the indoor coil to freeze up. This ice can prevent the system from working correctly. A clean filter is essential.
h4>Look at the Outdoor Unit
Is the fan spinning? Is the compressor running (listen for the humming/vibrating sound)? Is the unit free of debris like leaves, grass clippings, or toys? Clear anything blocking the sides or top.
h4>Listen for Strange Noises
Grinding, buzzing, loud clicks, or rattling sounds coming from the outdoor unit or compressor are signs of a mechanical problem. Turn the unit off immediately if you hear these sounds.
h4>Check the Thermostat Again
Is it set correctly? Is it calling for cooling (temperature set below room temp)? Is it in “Cool” mode, not “Heat” or “Fan Only”?
h4>Feel the Lines
If the unit is running (fan is on, maybe compressor too), carefully feel the larger insulated copper line coming out of the outdoor unit. It should be cold. If it’s warm or room temperature, the compressor might not be pumping, or you are low on refrigerant.
h4>Check for Ice
Look at the large insulated copper line and the coil on the outdoor unit. Look at the coil inside the air handler/furnace (if you can access it safely after turning off power). If you see ice, it means airflow is restricted (dirty filter, blocked vents) or you are low on refrigerant. Turn the system off and let the ice melt before troubleshooting further.
h4>Consider the Capacitor
As mentioned, a bad capacitor can cause the AC fan running but compressor not symptom. This part is located in the outdoor unit’s control panel. Testing or replacing a capacitor involves high voltage and should only be done by someone with electrical knowledge and safety tools. Visually, a bad capacitor might look swollen on top, but not always.
When to Call a Professional
Knowing when to stop DIY and call an HVAC technician is key. You should call a pro if:
- The AC unit won’t start at all after you’ve tried resetting the breaker and thermostat, and you’ve confirmed the breaker is on.
- The breaker trips again shortly after you reset it. This is a sign of a serious electrical problem or a compressor that is struggling or failed (AC tripped breaker fix is temporary).
- The AC fan running but compressor not symptom continues after resetting.
- You hear loud or unusual noises from the outdoor unit.
- You smell burning.
- You suspect a refrigerant leak (ice buildup, no cold air, hissing sounds).
- You’ve checked the basics (filter, clear unit) and the unit still isn’t cooling.
- You are uncomfortable performing any of the steps, especially those involving the electrical panel or outdoor unit disconnect.
- The problem started after lightning or a severe storm.
- You need help with resetting HVAC compressor and don’t feel safe doing it yourself.
A professional can diagnose complex issues like a failing compressor, a bad capacitor, a refrigerant leak, or electrical faults safely and correctly.
Preventive Steps
While resetting can help fix temporary issues, regular maintenance helps prevent them.
- Change Filters: Change your air filter every 1-3 months. This is the easiest way to ensure good airflow.
- Clean Outdoor Unit: Keep the area around the outdoor unit clear. Periodically rinse the outside of the coils with a garden hose (make sure power is off first!).
- Schedule Tune-Ups: Have a qualified technician perform yearly maintenance. They can check refrigerant levels, clean coils properly, test electrical components like the capacitor, and identify potential problems before they cause a breakdown.
Taking care of your AC system can help reduce the chances of needing to troubleshoot AC not cooling or dealing with an AC unit won’t start problem.
FAQ
h3>Frequently Asked Questions About Resetting Your AC Compressor
h4>How long do I need to wait after turning the power off before turning it back on?
Wait at least 10-15 minutes. This allows time for the system’s safety controls to reset and for pressure in the refrigerant lines to equalize.
h4>Can resetting my AC fix a refrigerant leak?
No. Resetting only cycles the power. It cannot fix mechanical problems like leaks or low refrigerant levels. If you suspect a leak (ice buildup, warm air, hissing), call a professional.
h4>My AC fan is running, but the outdoor unit is quiet. Is this fixed by resetting?
This symptom, AC fan running but compressor not, often points to an issue with the compressor itself, the run capacitor, or a safety switch that has tripped. While a reset might clear a temporary safety trip, if the issue persists, it’s likely a component failure (like a bad capacitor) that needs professional diagnosis.
h4>Is resetting the AC breaker the same as resetting the whole system?
Yes, resetting the circuit breaker is the most complete way to cut power to the entire AC system (indoor and outdoor units) for a reset. Turning the thermostat off and on is a power cycle but doesn’t remove power as thoroughly as the breaker.
h4>How do I find the right breaker for my AC?
Look at your main electrical panel. Breakers are often labeled. Look for “AC,” “Air Conditioner,” “HVAC,” or similar. It’s usually one of the largest breakers, often a double breaker (two switches connected). If they aren’t labeled, you might need to turn breakers off one by one until the AC unit loses power (confirm by trying to turn it on with the thermostat).
h4>Can I damage my AC by resetting it?
No, simply power cycling the unit by using the thermostat or breaker should not damage it, as long as you follow the waiting period. Repeatedly resetting a breaker that keeps tripping is not recommended, as it indicates a serious underlying problem that needs to be fixed.
h4>What does an AC compressor overload trip mean?
It means a safety feature in the compressor turned it off because it was getting too hot or working too hard. This can happen due to very high outdoor temperatures, dirty coils, low refrigerant, or internal issues. Resetting can clear the trip, but the underlying cause needs to be addressed if it happens often.
h4>My outdoor unit makes a loud hum but doesn’t start. What does that mean?
This often suggests the compressor is trying to start but can’t. A common reason is a bad start or run capacitor. Resetting might not help. This usually requires professional repair.
h4>How often should I reset my AC?
You should only reset your AC when you are troubleshooting a specific problem, like the AC unit won’t start or troubleshoot AC not cooling. It’s not something you need to do regularly as part of maintenance. If you need to reset it often, there is a persistent issue that needs investigation.
Summing It Up
Dealing with a hot house because your AC isn’t working is frustrating. Knowing how to safely perform an air conditioner breaker reset or a thermostat power cycle is a valuable first step in troubleshooting. Often, this simple action of resetting HVAC compressor can resolve minor glitches and get your cool air flowing again.
Remember to always prioritize safety by turning off power before working near the unit or breaker box. If resetting doesn’t work, or if you notice worrying signs like strange noises or smells, it’s time to call a qualified HVAC professional. They have the tools and knowledge to diagnose complex issues and perform necessary repairs, ensuring your system runs safely and efficiently. Regular maintenance is your best bet for avoiding breakdowns and keeping your AC compressor happy in the long run.