Your air conditioner is running, but the fan isn’t spinning. What happened? This is a common issue with home AC units and should be an easy fix.
If your AC fan isn’t spinning, the most likely cause is a bad capacitor. Check the capacitor, then call an HVAC technician to replace it.
The rest of this article will tell you everything you need to know about the capacitor in your AC unit, including a few ways to test it. As soon as you determine that a bad capacitor is causing the problem, you can quickly have it replaced and get your central air conditioning back to normal.
Table of Contents
- What Is An AC Fan Capacitor?
- Why Do Fan Capacitors Go Bad?
- How To Test Your Fan’s Capacitor
- Method 1: Manually Start The Fan
- Method 2: Inspect The Capacitor
- What To Do If Your Capacitor Is Bad
- Other Reasons Your AC Fan Isn’t Spinning
- Power Or Connectivity Problems
- Debris And Blockage
- Faulty Fan Belt
- Broken Fan Motor
- Related Questions
- How much does it cost to replace an air conditioner?
- Why is my air conditioner running but not lowering the temperature?
- How long does an AC unit last?
What Is An AC Fan Capacitor?
A capacitor is a small, cylindrical device inside your AC unit that stores and distributes energy. It’s like a rechargeable battery designed specifically for air conditioning units. Every AC unit has a capacitor that jump-starts the fan.
When you turn on your air conditioning, the capacitor sends a high voltage jolt to the compressor, blower motor, and fan belt. As the AC continues to run, the capacitor collects and stores energy, effectively recharging itself. A functioning capacitor does not need to be replaced or recharged.
Why Do Fan Capacitors Go Bad?
Even though capacitors are rechargeable, they can wear down and eventually break. This is a common issue for AC units and one of the main reasons an AC fan will stop spinning.
Here are a few stressors that will cause your capacitor to die or go bad:
- Heat: Overexposure to heat will shorten the lifespan of an AC fan capacitor. If you live in a hot climate, your capacitor will get overworked and wear down faster than in a cool climate.
- Age: Your capacitor isn’t built to last forever. On average, a standard AC fan capacitor will last for 20 years before it needs to be replaced.
- Voltage: All capacitors have a voltage rating. If your capacitor’s voltage is too low for your AC unit, it will still work, but it will have a much shorter lifespan.
If your capacitor has died, you shouldn’t try to replace it yourself. The safest solution is to hire an HVAC professional to get the job done. That way, you won’t have to worry about replacing the capacitor again for another 20+ years.
How To Test Your Fan’s Capacitor
Before you call an HVAC specialist, you have to check that your capacitor is actually dead. This is the most common reason an AC fan will stop spinning, but it isn’t the only possible cause. Fortunately, testing your capacitor is quick and easy.
To test your capacitor, you can try to manually start the fan, or open the AC unit and inspect the capacitor for visible signs of damage. Use both of these methods to make sure your AC fan capacitor is broken before you call a professional to replace it.
Method 1: Manually Start The Fan
The capacitor’s job is to jump-start the AC fan by supplying a jolt of electricity. If it isn’t working, the fan won’t be able to start on its own. You can check the state of your capacitor by manually starting the fan with a stick.
Find a long, thin wooden stick that will slide between the grates of your AC unit. Do not use a metal object for this. If your capacitor is working, metal will conduct the electricity and seriously shock you.
Using the metal stick, push one of the fan blades to start it running. If it suddenly starts up, the problem is most likely your capacitor. If the fan still doesn’t start, it could be another issue (check the bottom of this article for other common problems that stop an AC fan from spinning).
Method 2: Inspect The Capacitor
If you want to double-check that your capacitor is broken, open your AC unit to check for visible signs of damage. You must completely shut off all power to your AC unit to do this. If you don’t know how to disconnect the power, it’s safest to call a professional.
Step 1: Shut off the power to your AC unit using the disconnect or breaker panel. The panel is usually located on the outside of your house or garage.
Step 2: Remove the service panel, or grate, from your AC unit. You will need a screwdriver and a pair of heavy gloves to do this.
Step 3: Locate the capacitor. It’s a small metal cylinder with prongs connecting to wires at the top. Don’t touch the capacitor – this is just a visual inspection.
Step 4: Inspect the capacitor for signs of damage. You should be able to see corrosion, swelling, or leaking fluid without lifting it out of the AC unit. If you see any damage, keep the power disconnected and call an HVAC specialist.
What To Do If Your Capacitor Is Bad
Now that you know you have a bad AC fan capacitor; your next step is to have it professionally replaced. It is possible to replace the capacitor yourself, but it isn’t recommended. There is a high risk of serious or even deadly shock unless you have professional HVAC experience.
On top of that, an HVAC specialist will get the job done right the first time. If you hire a professional, you won’t have to pay for another fan capacitor replacement for years to come.
Make sure you shut off your AC unit while you’re waiting for the replacement. Running the air conditioner with a bad fan capacitor will put strain on the fan motor and can eventually cause it to break. That could lead to much more expensive repairs!
Other Reasons Your AC Fan Isn’t Spinning
A bad capacitor isn’t the only problem that can cause your AC fan to stop spinning. Power issues, fan motor issues, and even blockage from debris can also affect the fan. Most of these problems are hard to spot if you aren’t an expert.
If you tested your capacitor and it doesn’t seem to be broken, you should call an HVAC professional to diagnose the problem. They’ll let you know what your next steps are and if you need to replace your whole AC unit.
Here are a few other issues that could stop your AC fan from spinning:
Power Or Connectivity Problems
If your AC isn’t running and the fan isn’t spinning, it could be a simple power issue. Circuit breakers often trip and shut off when they get overheated. Flip the switch on your circuit breaker to reset it, then try to turn on your AC again.
Debris And Blockage
Debris sucked inside your AC unit can block the fan blades and stop them from spinning. If you notice a lot of debris around your fan, try to unblock it with a wooden stick. You may need to shut off the power and remove the grate to manually clean out the fan.
Air filters can also get blocked by debris, which restricts airflow to your AC unit. This will cause ice to build up in the unit if you live in a cold area. Replace your air filters regularly to prevent blockage.
Faulty Fan Belt
The fan belt, like your AC fan capacitor, can wear down and break over time. Your fan belt might have slipped out of place or snapped from overuse. Fortunately, the belt can be quickly replaced for a low cost.
If your fan belt has broken, that’s a pretty good sign that your whole AC unit is getting older and might need to be replaced. Replacing the belt is a temporary fix. Talk to an HVAC company about updating your AC unit to avoid more expensive problems in the future.
Broken Fan Motor
If your AC is running but isn’t blowing cold air, the problem might be your AC fan motor. Unfortunately, this is a more complicated fix than replacing the capacitor.
While the capacitor starts the fan, the fan motor is what powers it and keeps it running. If you run your AC unit a lot in hot conditions, the motor can get overworked and eventually burn out. A burnt-out fan motor needs to be replaced right away.
Your HVAC specialist might recommend a full system replacement if your fan motor is broken. This seems like a big investment, but it’s the easiest way to save on future repair costs. AC units aren’t built to last forever!
How much does it cost to replace an air conditioner?
If you need to replace your entire AC unit, be prepared to invest $1,500-$4,000 for the device and installation service. The exact cost will depend on the size of your home and the type of AC unit you want to install.
The initial price is high but remember this; a brand-new AC unit installed by a professional will function for years without expensive repairs.
Why is my air conditioner running but not lowering the temperature?
If your AC unit is on but isn’t actually cooling your home, the problem might be your thermostat settings. Aside from that, it could be a blocked air filter, leaky duct, or low refrigerant. Call an HVAC specialist to diagnose the problem.
How long does an AC unit last?
The exact lifespan of your AC unit will depend on its model and the year it was made. In general, a central AC system can last for around 20 years without replacement. Modern AC units will last even longer.
If you live in a hot climate and run your AC frequently, it will wear down faster. Routine maintenance and inspections are important to keep it from overheating.