AC Capacitor Function: What Is It For?

Air conditioning systems contain an intricate network of coils, wires, and other parts that keep homes cool during hot Florida summers. The AC capacitor is among those parts. If your AC capacitor doesn’t function properly, your whole system won’t work.

As the top service providers for heating and air conditioning in Vero Beach, FL, we often handle calls where the AC capacitor function fails. In the paragraphs below, learn more about how it should function, common symptoms that indicate a breakdown, and what to do if yours won’t work. Call us at (772) 773-6926 if you recognize any of these issues. 

What Is an AC Capacitor?

An AC capacitor looks like a cylindrical battery and acts as a store for electrical power. The power helps your system begin cooling cycles. They work similarly to a car battery, providing just enough power to start the system.

When capacitors fail, your air conditioning system will struggle to function efficiently, driving up your power bill in the process. Such failures might also cause other components to break down from excessive wear and tear. This leads to expensive part replacements and repairs in the future.

How Does an AC Capacitor Function?

Your air conditioning system requires lots of power to maintain your preferred indoor temperatures. The AC capacitor will store electrical energy to provide the jumpstart needed to make the AC motor start cycling. When your AC has sufficient energy to run, the capacitor decreases the energy output to a small but steady amount that keeps your system running.

Each capacitor has a voltage rating that specifies how much energy it can handle at one time. For example, a capacitor with a rating of 50 volts can tolerate up to 50 volts of energy. When more voltage travels through the capacitor, the component might short out. 

Types of AC Capacitors

Most air conditioning systems contain two types of capacitors: start and run. Each AC capacitor functions at different points. A start capacitor delivers that initial jolt of electrical energy that kick-starts the cycle.

The run capacitor uses previously stored energy to keep the motor running throughout the cycle’s duration. Larger systems will typically use a dual capacitor, which requires two capacitors within the same case. Other systems use two single capacitors.

We often recommend a dual capacitor instead of a single capacitor. They save space and work more efficiently. If your capacitor stops working, we can more easily replace it.   

Symptoms of a Dysfunctional AC Capacitor

How can you tell if you have a malfunctioning AC capacitor? Most AC capacitors can last up to 20 years and provide signs that they need replacing. Some circumstances can shorten your capacitor’s lifespan, including:

• Extremely hot temperatures
• Power surges
• Lightning strikes
• Overworking due to other failing components or lack of maintenance

Whether you experienced these occurrences recently or you just have aging components, you might notice your system exhibiting some of these symptoms:

• Your unit doesn’t start when indoor temperatures rise above thermostat presets
• Your system powers down at random
• The vents don’t produce cool, refreshing air
• Your unit produces strange humming sounds during operation
• Your energy bills have increased substantially
• Your unit emits smoke or burning odors

If you observe any of these signs, you need to call for professional repair services. You should never attempt to troubleshoot your capacitor on your own. AC capacitors emit strong electrical currents. Without proper training and appropriate tools, you could sustain severe injuries from electrocution.

Capacitor Testing

A professional HVAC technician can test your capacitor on a service call when your AC isn’t working as expected. Your capacitor might appear undamaged on the surface. However, it could sustain internal damage that the naked eye won’t detect.

Your technician will have tools that allows them to easily test the AC capacitor function. Using a multimeter, they can check for electrical current, resistance, and voltage. When they identify the problem, they can help you review your options.

Sometimes the problem occurs from wiring issues. Loose, faulty, or burned wires can cause the capacitor to stop working reliably. When a capacitor itself sustains damage, it often requires complete replacement.   

Capacitor Replacement

When a licensed technician finds capacitor damage during a test, they’ll recommend replacements that work with your budget and system. The price of a new capacitor ranges between $80 and $400. The price depends on the brand name and your system's requirements.

We recommend choosing a quality capacitor from a reputable manufacturer. Otherwise, you could end up with system damage or premature part failure due to factory defects or unreliable materials. These issues can cause further damage to your AC system.

Experienced HVAC technicians can usually replace your capacitor within an hour or less. 

How To Prevent Expensive AC Repairs or Replacements

After seeing the hefty bill that accompanies capacitor problems, you probably want to know how to avoid expensive repairs. Since you can’t replace capacitors by yourself without risking serious injuries, you can take other steps to keep your system fully functional and efficient. We recommend scheduling regular HVAC maintenance services each year.

Your system will sustain some damage after years of use and exposure to extreme weather and temperatures. However, our maintenance services protect your system from additional issues associated with unrepaired problems. We’ll quickly pick up on mild damage, small repairs, and connection issues that cause bigger problems later.

We’ll calibrate your system to maintain optimal performance throughout the year. Professional maintenance services offer an economic and efficient way to prevent problems before they occur.

Protect Your HVAC System with Our Dependable Services

At Bates Air & Heat, we’ll give you an estimate before replacing the part. Learn more on our blog about issues like your AC unit not blowing cold air.

If your system works improperly because of decreased AC capacitor function, contact our professionals at Bates Air & Heat in Vero Beach, FL. When you have AC problems, you can reach us for timely HVAC services at (772) 773-6926 or contact us online to schedule an inspection.