Hundreds of components in an air conditioning system complete its entire structure. Among them, one of the most important parts is the capacitor. It’s shaped like a soda can and resembles an aluminum cylinder. Let’s explore what it is, how it works, and how to test the signs of a bad capacitor.
What is a Capacitor?
A capacitor is a Cola-like can that stores electrical energy. The cylinder-shaped device kick-starts the AC motor, which delivers an initial boost to the cooling cycle. Inside the cylinder, aluminum or mice are divided by some insulation material. The setup allows capacitors to store energy in an electrostatic field and provide constant voltage to the DC power supply.
Even if there are any fluctuations in the main AC power supply source, the energy stored is pushed onto the power circuit as needed.
3 Major Types of AC Capacitors
In most HVAC systems, there are three major types of capacitors. Such as:
1. Start Capacitors
First of all, we have the Start Capacitor — as it sounds. It provides a quick jolt to the AC’s motor and delivers an initial burst of electricity to start the cooling cycle. Thus, it works only briefly until the system gets started and runs smoothly. Just like giving a sprinter a push at the start of a race — it’s all about that quick burst of speed.
2. Run Capacitors
On the other hand, once the AC is humming, the run capacitor takes over. It supplies a steady state flow of low-voltage electricity. Unlike its counterpart, the run capacitor stays engaged throughout the operation. It stores and releases the electricity to maintain a steady current. It’s akin to a long-distance runner who paces themselves to maintain stamina across miles rather than seconds.
3. Dual Capacitors
A type of capacitor that does the work of starting & running capacitors at once. Yes! It’s often found in more modern AC designs. The design is like a soda can-shaped that saves space and simplifies the internal structure. This single canister can handle both starting and running duties. Thus, troubleshooting is easy if something fails.
How do Capacitors Function?
Capacitors are often compared to batteries because they store electrical current and release it when needed. Since our home electrical source is the grid station. It gets the high Voltage directly from the meter. To reduce the ultra power effect, only capacitor throws are required.
That’s why replacing a capacitor is not as simple as popping a new battery into a device. The task should be left to professionals, as incorrect handling can lead to electrical shocks or damage to your system.
Understanding Capacitor Specifications
The power of a capacitor is measured in Voltage and microfarads (MFD). The Voltage indicates how fast the electrical current moves through the capacitor. Likewise, the microfarads measure the capacity of the capacitor to store this current. Most capacitors typically range from 5 MFD to 80 MFD.
Numbers of Capacitors in AC Unit
It integrates both functions into a single unit and simplifies the overall design. That’s why the setup with two single capacitors offers a notable advantage. Thus, if one capacitor fails, a single one can be replaced to save cost.
Remember that both have different duties; they may wear out at varying rates. Only professional technicians will finalize whether it needs changes or not!
You may ask if there is a need to increase the number of capacitors.
Well, it’s not as long as the pair is working to the best of their collaboration.
5 Common Issues of Faulty AC Capacitors
Below are the consequences of a faulty capacitor:
1. Drop in Performance
A failing capacitor can’t maintain consistent power delivery to the AC system. Thus, it results in uneven cooling and reduced performance. It also makes it challenging to keep your home comfortably cool.
2. Increased Operational Costs
Faulty capacitors cause the AC system to run longer and work harder. As a result, it increases energy consumption. So, you get higher utility bills, like driving a car that has lost fuel efficiency.
3. Hard Starting
Capacitors provide the necessary energy burst to start the AC compressor. When they fail, the system may hesitate or stutter upon startup.
4. Frequent System Shutdowns
AC units may overheat or need a steady energy supply from a suitable capacitor to maintain operation. That’s why you have to experience unexpected shutdowns. This is akin to a computer crashing due to an insufficient power supply.
5. Compressor Overload
A malfunctioning capacitor puts additional strain on the AC compressor — one of the most vital and expensive components. It can lead to premature wear and potentially costly repairs or replacements.
6 Symptoms of a Bad AC Capacitor
Below are some of the most common signs when a capacitor gets terrible:
1. Blower Motor Failure to Start
When your AC’s blower doesn’t kick into gear, the issue is often due to a failing capacitor, which cannot store enough charge to power the blower motor. Your indoor air stays stagnant and warm since it lacks the energy to start the motor.
2. Unexplained Increase in Energy Consumption
Seeing your energy bills rise without an apparent reason could be a warning sign. When capacitors deteriorate, they force the AC system to work harder. Thus, to maintain the same level of cooling, AC has to work more than usual.
3. Persistent Humming Sounds
A constant humming noise from your outdoor AC unit can indicate a struggling capacitor. The sound may resemble a car engine that’s left idling too long. It means the capacitor is trying and failing to power up the system. The noise calls for help and signals that the capacitor cannot correctly start without intervention and might lead to a system shutdown.
4. Random System Shutdowns
If your AC unit turns off randomly, it is similar to a computer crashing unexpectedly. It’s another sign of a suffering capacitor. When it fails, the system lacks the consistent energy flow required and shuts down sporadically.
5. Complete Lack of Power
When the AC won’t turn on, it’s like a flashlight that fails to turn on because its batteries are dead. In this scenario, the “battery” of your AC, the capacitor, might be wholly depleted or damaged.
6. Signs of Overheating
The presence of smoke or a burning smell emanating from the AC’s exterior components. These can be as alarming as seeing smoke billow from under your car’s hood.
5 Causes of a Capacitor Failure
Below is the explanation of what happens when after a capacitor failure:
1. Age and Wear
Like most components, capacitors have a limited lifespan. Over time, the stress of continuous switching on and off gradually wears out. Typically, a capacitor might last anywhere from 10 to 20 years. Yet, excessive heat and frequent cycling can shorten this lifespan significantly.
2. Heat Exposure
Capacitors are sensitive to high temperatures. Since they are sheltered inside, the extended exposure to high heat can cause the chemicals inside the capacitor to degrade or the capacitor’s metal parts to expand. It results in physical damage or reduced functionality. This is more common in outdoor AC units in direct sunlight or poorly ventilated spaces.
3. Voltage Fluctuations
Surges or fluctuations in the power supply can overstress the capacitor beyond its voltage rating benchmark. These voltage spikes can occur due to lightning strikes or irregularities in the home’s electrical system.
4. Incorrect Sizing
A capacitor that is not of the correct size or is of poor quality can lead to early failure. The capacitor must be precisely matched in specifications (Voltage and capacitance) to the motor it powers. It won’t meet the proper energy requirement if it’s too large or small.
5. Electrical Failures
Faulty electrical components or wiring within the AC unit can also lead to capacitor failure. Short circuits and damaged wires can cause abnormal electrical behavior and overstress the capacitor.
How Long Do AC Capacitors Last?
Because it has to bear the power outages and the generator’s electricity shocks, keep in mind that you may have to replace them twice as per the lifetime of the AC.
Got it?
How to Test the Health of AC Capacitors?
Testing a capacitor isn’t as simple as checking the refringent leakage or clogged air filters. The health of a capacitor is determined after measuring the capacitor’s Voltage, current, and resistance value. It’s a hazardous job; only verified technicians can do it.
Our HVAC experts will be there soon at your doorstep, and they will perform the test this way:
- Safety First: Our technician will use a circuit breaker to eliminate the risk of electric shock.
- Accessing the Capacitor: The technician opens the compressor unit’s panel to reach the capacitor.
- Discharging the Capacitor: He uses an insulated screwdriver to short the terminals to discharge the capacitor and prevent accidental discharge safely.
- Removing the Capacitor: The wires are carefully disconnected from the capacitor, noting their configuration to correct reconnection later.
- Measurement: Then, he will set a multimeter in capacitance measurement mode and connect its leads to the capacitor’s terminals to read the capacitance value.
That’s why you don’t do it at any cost if you’re an average house owner.
Just call Ventiluxes.
Can You Replace AC Capacitors by Yourself? – Is it Possible?
If you’re experiencing issues with your AC system and suspect it might be related to a faulty capacitor, contacting a professional service like Ventiluxes can be wise. They can handle the job safely and efficiently, providing peace of mind and high-quality service.
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