4 Safe Steps to Test an AC Capacitor
Do you know how to test an AC capacitor? If you are the DIYer type, learning how to test an AC capacitor is one task you should have up your sleeves to maintain your air conditioning system in top shape. That’s because a bad capacitor can cause various issues, such as poor cooling performance or complete system failure.
On the other hand, when you test the capacitor before swapping it, you save yourself headaches with unnecessary expenses and can spot the issue from the get-go. While the process is relatively simple, we recommend following certain procedures and using the right tools for safety and accuracy.
That’s why we’re walking you through the process of testing an AC capacitor. And if you ever need professional assistance, our team at Service Minds One Hour Air Conditioning & Heating in Tampa is ready to help with reliable HVAC maintenance and repair services.
What is an AC Capacitor, and How Does it Work?
An AC capacitor is a small electrical component that stores and lets out energy to help power your air conditioner’s motors. These motors include the compressor, condenser fan, and blower motor.
The capacitor gives the unit the extra energy to start and keep the motors running as they should. Without a working capacitor, your AC system’s motors would struggle to work properly or may not run at all.
Capacitors are measured in microfarads (MFD), which indicates the amount of electrical charge they can hold, and voltage, which shows how much power they can safely handle.
While capacitors might seem similar to batteries, they don’t store energy long-term. Instead, they release energy quickly when the motor requires an extra boost.
Overall, AC capacitors can last between 5 to 15 years in good condition.
Different Types of Capacitors
Air conditioners use several types of capacitors, each with its own specific function:
1. Start Capacitors
The start capacitors provide a large gush of energy to get the motor running. They’re only used for short periods, typically when the motor first starts.
2. Run Capacitors
Unlike start capacitors, run capacitors deliver a continuous flow of energy to the motor while running, helping to maintain steady operation.
These are commonly found in AC units and keep the compressor and fan motors working efficiently.
3. Dual Capacitors
These combine the functions of both start and run capacitors into a single unit. Dual capacitors have three terminals labeled “C” for common, “Fan” for the fan motor, and “Herm” for the compressor motor.
You can often find them in systems with two motors, like many residential air conditioning units.
What Types of Units Have AC Capacitors?
You can usually find capacitors in air conditioning systems that have single-phase motors. These motors require extra energy from a capacitor to start and run like a horse.
Permanent split capacitor (PSC) motors are another common type of motor that you can find in residential air conditioners. PSC motors rely heavily on capacitors to keep the system running consistently.
So, if you have a home AC unit, chances are good that it uses one or more capacitors.
How to Test an AC Capacitor?
Now, let’s get down to business. If you want to test an AC capacitor, the process is straightforward. However, we recommend that you follow these steps to the letter:
Step 1: Check AC Capacitor Ratings
Before starting, find the capacitor’s working voltage and capacitance (electrical capacity) value on its label. These ratings are central in this step, as you’ll need to compare your test results and figure out whether the capacitor is working correctly.
Step 2: Turn Off the Power Supply
To avoid any risk of electric shock, head to your breaker box and shut off the power to your air conditioning unit. Always make sure there is no power coming to the unit before continuing.
Step 3: Discharge the AC Capacitor
A word of caution here: capacitors can hold electricity even after the AC unit is off. So, to avoid injury, use insulated tools to shorten its terminals and discharge the capacitor.
This step is super important for your safety before you test the device.
Step 4: Get Capacitor Readings Using a Multimeter
Set your multimeter to measure capacitance. Connect the multimeter test leads to the capacitor terminals (C and Fan or C and Herm for dual capacitors).
The multimeter will display a reading in microfarads (MFD). Compare this reading with the value printed on the capacitor. If the reading is more than 10% below the labeled value, the capacitor is likely bad, and you should replace it.
The bright side is when you take the time to test your AC capacitor, you can help prevent significant problems. Not only that, but you make sure that your AC system stays in good working order for a long time.
Signs That Your AC Capacitor is Bad or Failing
At this point, you may be wondering how to know when your AC capacitor is wonky or on its last legs. Don’t worry. You will spot several signs showing trouble. Here’s what you should watch for:
- Higher Energy Bills: A faulty capacitor may drop your AC unit efficiency. This jacks up your energy consumption.
- Smoke or Burning Smells: A damaged capacitor can sometimes release a smoke or burning odor.
- Lack of Cool Air: If the capacitor isn’t working, the compressor may not be able to run. This is when you get warm air instead of cool air.
- Unusual Noises: Clicking, buzzing, or humming sounds could signal that the motor is struggling to start due to a failing capacitor.
- Slow Cooling Cycles: If your air conditioner takes longer to cool your home or randomly shuts off, the capacitor might be the culprit.
- Frequent AC Shut-offs: If you have a worn-out capacitor, your AC unit may shut off unexpectedly, disrupting the cooling cycle.
Test your AC capacitor for any of these symptoms in case you have doubts. If necessary, replace it.
Ready to Test an AC Capacitor: Service Minds on the Way
Testing an AC capacitor is a simple yet important step in keeping your AC system. You just need the right tools and steps. But we also understand that this process can be intimidating at first. So, if you’re not comfortable testing or replacing the capacitor yourself, getting a pro is a smart move.
Are you in the Tampa area? Our team at Service Minds One Hour is here to help. Our skilled HVAC techs are like superheroes. They are always ready to swoop in, handling top-notch services from AC maintenance to complex repairs.
And the best part is that we are always on time, or you don’t pay a dime. So, you don’t have anything to lose. Satisfaction guaranteed! Call us today!