Why Do AC Capacitors Fail: Three Possible Causes

Your AC capacitor may be the most important part of your air conditioner that you’ve never heard of. However, if your AC capacitors fail during the hottest months of the year, it affects your entire air conditioning system. 

At Comfort Specialists, we’re Roxbury Township's reliable AC repair experts. We understand the complex ins and outs of air conditioning, including the answer to the question, “Why do AC capacitors fail?” Below, we’ve compiled three of the most common reasons AC capacitors fail.

What Is an AC Capacitor?

Air conditioning capacitors are small cylinders that store electricity. Located in your AC’s condenser unit outside your home, capacitors create and provide the bursts of energy necessary to start and run your air conditioner. 

Capacitors typically come in pairs, either as two individual units or together as a dual capacitor system. The start capacitor provides the extra voltage required to jumpstart your AC’s fan and compressor. Without a start capacitor, your home’s energy source may not have the power necessary to start your air conditioning systems. After your AC starts, the run capacitor takes over and provides enough voltage to keep the fan and compressor running. 

If one or both of the AC capacitors fail, your air conditioner won’t work properly. If left unaddressed, it could end up costing you in repairs or even replacement of your AC unit. So, why do AC capacitors fail? Below, we give an overview of some of the most common reasons for AC capacitor failure. 

1. Overheating

Like many electrical components, AC capacitors are sensitive to heat and, therefore, prone to overheating. Because your AC capacitor is in the outdoor portion of your air conditioning unit, it sits in the sun all day long, which may result in overheating. 

The capacitor may also overheat if the air conditioner runs too hard for too long. This is why it’s essential to make sure your air conditioner is the right size for your space and that you keep it properly maintained. Changing the filter every few months and scheduling regular maintenance appointments can help take some of the burden off your capacitor during peak cooling times. 

2. Power Surge or Overload

Chances are low that your home or AC unit will get hit by lightning, but it could happen. A sudden energy spike from something like a lightning strike overloads the capacitor and fries it, burning it out and destroying it. Minor power surges or other fluctuations in power also overload the capacitor and may cause it to fail. 

Your AC capacitor may also fail if the fan motor burns out or is somehow impeded from spinning freely. The capacitor continues to send power to try and operate the fan but eventually overloads and burns out. Additionally, if your capacitor is the incorrect size or has the improper voltage required to adequately power your air conditioner, it may burn out.

3. Worn Out or Damaged Parts

Like any mechanical component, AC capacitors wear out over time. Depending on the amount of use, they can last up to 20 years. However, other factors, such as length and frequency of use, as well as prolonged high temperatures or humid environments, also affect the lifespan of your capacitor. 

If the air conditioning unit isn’t working correctly, your capacitor may sustain damage. A fan motor or compressor with worn-out bearings may cause the capacitor to work harder and fail. If the relay switch on your air conditioner malfunctions, it may cause the capacitor to overheat. Damage from lightning or power surges also affects the capacitors, causing them to fail. 

Comfort Specialists | Your Choice for AC Service in Roxbury Township

When you choose Comfort Specialists, you’re choosing a team of experienced technicians with your comfort and satisfaction in mind. Whether you’re asking, “Why do AC capacitors fail?” or wondering if carbon monoxide poisoning from AC is something you should be concerned about, we can help. 

With over ten years of experience and thousands of happy customers, our team of professional contractors handles any HVAC or electrical need that may arise. We offer satisfaction guarantees on our workmanship and equipment for as long as you own your home. We also provide 24/7 emergency services (with no additional charges for nights and weekends) and financing options to ensure that comfort fits into your budget.

For the most comprehensive air conditioning services in Morris County and beyond, contact Comfort Specialists. Call us today at 973-490-4881 to schedule a consultation.