Updated at: 07-03-2023 - By: Sienna Lewis

Do you know what an air conditioner’s capacitor does? The capacitor is the most important part of an air conditioner. While that’s a good thing, this is also why it falls down so quickly.

Besides storing electricity, capacitors are also responsible for the air conditioner’s cool airflow. This article will provide you with the knowledge you need to better comprehend an AC capacitor.

What is an AC capacitor?

Air conditioning systems use a type of capacitor known as an AC capacitor, or “run capacitor,” which is a cylindrical item that provides energy to the motor. In addition to boosting your AC system’s initial power, the AC capacitor delivers continuous power to keep it functioning.

An air conditioning system’s capacitor is merely one part of the system as a whole. To be sure, this little worker, like the rest of the air conditioning system, is built to last. Your system won’t work properly if you don’t have a functioning capacitor.

What is an ac capacitor? And what does a capacitor do in an air conditioner? 7 steps to repair air conditioner.

Here’s all you need to know about the capacitor and how to troubleshoot and replace a broken one if you feel it’s faulty.

Types of Air Conditioner Capacitor

1 Electrolytic Capacitor

The + and – symbols on the leads and polarity of this air conditioner capacitor indicate its intended use. After diodes have rectified the DC voltage, it is commonly used to smooth it out. They helped to reduce the DC supply’s ripples. The bigger the capacitance of the capacitor, the less the ripple. Simple linear power supplies with step-down transformers demonstrate this application.

2 Safety Capacitor

The air conditioner’s inverter control circuit is usually equipped with safety capacitors. They are employed in the circuit’s live sections and can be classed as either X or Y types. It is important to be cautious when handling these capacitors because even if the power is turned off, there is still a small amount of charge that might lead to an electric shock.

In order for a device to function properly, it must have a method of removing any remaining charge from it after the air conditioner has been turned off. Before utilizing any capacitors, check to see if they have the appropriate certification marks, such as VDE, UL, or CE.

insulated gate bipolar transistors rapidly switching the AC supply generate harmonics, which are reduced by using capacitors in conjunction with inductor coils (IGBT).

3 Ceramic Capacitor

High-frequency content is bypassed using ceramic capacitors, which are employed as bypass capacitors They can be used to bypass high-frequency circuit noise that could harm delicate circuitry by being connected in series with the DC power input of integrated circuits.

Surface-mount capacitors are becoming more widespread in multilayer printed circuit boards as transformerless power supplies become more common due to their greater efficiency and reduced size. The harmonics created by the rapid switching of the AC power supply by the insulated gate bipolar transistors are reduced by using these capacitors and inductor coils (IGBT).

4 Capacitors for Starting and Running Air Conditioner

Single-phase electric motors frequently employ these capacitors. A capacitor-start motor’s START and RUN windings are connected by a START capacitor. The starting torque generated as a result of this difference was sufficient to start the motor even when it was coupled to a full load.

Additional torque can be gained by using the RUN cap. to fine-tune phase differences between the two windings. Single-phase compressor markings help identify the motor’s connections. Those are R, S, and C (corresponding to the RUN, START, and CUT windings, respectively). (common of the two windings).

Structure Characteristic of Air Conditioner Capacitor

1) The air conditioner capacitor’s working medium is aluminum foil, which is anodized to generate a very thin coating of aluminum oxide (Al2O3). The oxide dielectric layer and the capacitor’s anode form an integrated system that is mutually dependent on one another. Capacitors have electrodes and dielectrics that are completely separate from one another.

When it comes to air conditioner capacitors, the actual surface area is substantially larger than the apparent surface area of the anode and cathode aluminum foils. Capacitors are used in air conditioning systems for this very reason. Liquid electrolyte is frequently required because of the usage of aluminum foil with numerous finely etched holes.

3a) In the capacitor, the negative foil serves as an electrical conductor. As a result of the air conditioner capacitor’s cathode being electrolyte, an electrical channel must be constructed through another metal electrode and other sections of the circuit.

It is possible to intentionally and precisely control the thickness of the dielectric layer of the air conditioner capacitor because the anodic oxidation process produces the dielectric oxide film and its thickness is directly proportional to the applied voltage.

It is because of the air conditioner capacitor’s structure and operations that the air conditioner is able to perform normally. The capacitance value of the capacitor should be examined before it is inserted in the circuit to avoid short circuits, open circuits, and leakage. Make sure that the capacitor type, capacity, withstand voltage, and other markings are clearly visible when you install it.

The following points are introductions to air conditioner capacitor structure characteristics. Air conditioner capacitors aren’t just for cooling systems. However, there are several uses, including air conditioning inverters, color televisions, displays, LED lighting, and energy-saving bulbs. Capacitors used in air conditioners are most commonly found in home appliances, where their use is more widespread.

AC Capacitors are Main Reason for Failure in A/C & Heat Pumps

Bad AC Capacitor Symptoms

This could be the reason why your air conditioner isn’t blowing cold air: faulty capacitors

In the beginning, though, start with the simplest solutions: It’s possible that you need new air filters, but there are a number of additional possibilities.

It’s possible that your unit’s capacitor has to be replaced once you’ve ruled out the other possibilities.

The following are the most prevalent symptoms of a malfunctioning AC capacitor:

  • Heating and air conditioning units aren’t producing chilly air
  • When you switch on the air conditioning, it takes a bit to get going.
  • The sound of a humming from your air conditioning system
  • HVAC system shuts down by itself
  • When I turn on the AC, nothing happens.

Working Principle of Air Conditioner Capacitor

To start the air conditioner, the capacitor is essential. It is currently common practice for air conditioners to start and operate using capacitors. As a result of the damage to the capacitor, the air conditioner’s start current will climb too quickly, and the compressor will either fail to start or automatically power off during the startup process if the protective mode is activated. In order for the compressor to start up normally, the capacitor functions as conduction.

When your air conditioner is running, the capacitor accumulates and stores energy; in other words, it acts like a rechargeable battery. Thus, when your air conditioner needs a lot of energy, the capacitor can provide it and keep everything running properly. It is the compressor that powers the air conditioner’s compressor, blower motor, and fan motors, which all rely on the compressor to keep running and cool air flowing through your house.

Main Reasons for the Failure of Air Conditioner Capacitor

Using an air conditioner more frequently than normal increases the load on a capacitor’s lifespan. Although perfect circumstances are rarely realized, most capacitors are designed to survive twenty years under ideal conditions. For the vast majority of capacitors, there are three primary causes of failure:

1 Heat Exposure

The term “heat exposure” refers to the fact that one has been exposed to heat.

2 Voltage Capacity

Each capacitor in an AC air conditioner has a specific voltage rating. Capacitors with higher voltage levels are more expensive, so switching to a lower voltage level capacitor may be an attractive option. This, however, increases the capacitor’s lifespan by a large amount.

3 Shorter Lifespan

Aside from the fact that most capacitors have a twenty-year lifespan, this also means that they are only usable in particular scenarios. A capacitor with defective parts will have a shorter lifespan if it is older and consumes a lot of electricity.

As a result of an AC capacitor failure, additional components may be harmed. You should replace the capacitor as soon as you notice a problem with a fan or an electrical connection, to avoid additional costs and maintenance.

How to Test an AC Capacitor

If you see any of the above-mentioned symptoms, go outdoors to the condenser unit of your air conditioner.

The fan on top of the device can be seen via the vents. Locate a long, thin object if your air conditioner’s fan won’t turn on (a stick, screwdriver, pliers). The blades of the fan can be gently pushed into the vent. You have a defective capacitor if the fan starts spinning on its own and continues to do so.

Capacitor failure is the most likely cause of a buzzing noise from your air conditioner.

How to Replace an AC Capacitor

There are replacements available at your local hardware store. After that, you may begin installing:

A breaker panel can be used to turn the electricity off to your air conditioning system.

Step 2: Remove the condenser unit’s side panel to gain access to the capacitor.

Discharge the electricity from the capacitor.

Step 4: Remove the old capacitor and observe how the wires are connected to each other.

Unscrew all three HERM, Fan and C capacitor connectors from the motherboard. Remember which colour wires connect to which connector by taking a picture or making a note.

Step 6: Replace the old capacitor in accordance with the manufacturer’s instructions.

Step 7: Replace the condenser unit’s side panel.

How to Choose a Replacement Capacitor

Choosing the correct AC capacitor replacement is a must if you’re going to do it yourself. When it comes to replacing a capacitor, size and shape aren’t as important as the voltage rating and the microfarads (F).

The microfarad rating must match your current capacitor’s, even if the voltage rating is different. Your capacitor’s voltage and microfarads are clearly labelled, and may say “35/5 F and 370V.” Remember to include this and your air conditioner’s model and manufacture when you go shopping at a local home goods store.

What really matters is that you get the correct voltage (and microfarad) for the capacitors you need, regardless of the form or size of the capacitors themselves.

Frequently Asked Questions about Air Conditioner Capacitor

1. What does a capacitor do for an air conditioner?

If you want to start your air conditioner with a full charge, you need capacitors. Capacitors do this by exchanging electrons between the two conductive plates that make up the device.

2. How much does it cost to replace a capacitor on an air conditioner?

The typical price of an HVAC capacitor is $170. Professional installation is included in the price of $120 to $250. Branded products might cost as much as $400 or more. Brand, model, voltage, and labor costs all play a role in the final pricing.

3. How long does an AC capacitor last?

The air conditioner capacitor has a lifespan of between 10 and 20 years. However, heat exposure is one element that can shorten their lives. Having a capacitor that’s too small or designed with the wrong components can shorten its life expectancy.

4. Why is AC running but not cooling?

There’s a Blockage in the Condenser Unit

5. Can I replace the AC capacitor myself?

You certainly can. Alternatively, it might be a capacitor or a compressor. To see if it’s the capacitors, it’s possible to do a self-diagnostic and then call in a technician if the problem still persists. When it comes to fixing or replacing a capacitor, there is no “DIY” fix.

6. How do I know what capacitor to get for my AC?

The full load amps should be multiplied by 2,650. This quantity is multiplied by the voltage of the supply. The owner’s manual will list the total amps drawn and the voltage supplied. The capacitor’s MicroFarad value is the outcome of this calculation.

7. Do air conditioner capacitors get weak?

Capacitor failures are also possible as a result of power surges.

A summer thunderstorm’s lightning strike might clearly overwhelm and burn up your HVAC’s electrical equipment. Capacitors can be damaged over time by even weaker power spikes. Weaker spikes in the electrical grid may be to blame for these occurrences.

What Size Capacitor Do I Need For Air Conditioner?

8. Should I turn off AC if it’s not cooling?

It’s time to do one more thing if your air conditioner isn’t working. This can’t be stressed enough. Your HVAC service company can help you by turning it off. Whenever a customer’s air conditioner isn’t cooling adequately, we instruct them to turn it off.

9. What does a bad capacitor look like?

Typically, poor caps have a bloated or domed top. The electrolyte can also seep out of particularly faulty caps on occasion. Afterwards, you may notice a brown crust surrounding the capacitor or even on top of it.. Most of the time, it has the appearance of a stale coffee stain.

Sansone AC Repair Services in South Florida

There is no better choice than Sansone when it comes to AC capacitor replacement. We’ve been in business for more than four decades, and we’re proud to offer the greatest HVAC services and customer attention to people of South Florida.

To learn more about our fast, efficient, and cost-effective AC repair services, give us a call or fill out the form below to get started.