The most frequent problems with aircon capacitors and how these can be repaired or replaced.

The aircon capacitor plays a vital role in providing the necessary power to start and run the motor of the air conditioning unit. If the aircon capacitor malfunctions, it can cause the system to fail, resulting in inconvenient breakdowns and costly repairs.

1. Capacitor Failure Due to Ageing

Like any electrical component, aircon capacitors are subject to wear and tear over time. Capacitors have a finite lifespan, typically around 5 to 10 years, depending on the quality of the capacitor and the frequency of use. As the capacitor ages, its ability to store electrical charge diminishes, leading to inefficient operation and eventual failure.

Symptoms of an aged capacitor include an aircon unit that fails to start or has difficulty starting, producing unusual humming noises, or running inefficiently. The solution to this issue is to replace the old aircon capacitor with a new one. If you notice any of these signs, it is recommended to have a professional technician inspect and replace the faulty capacitor before it leads to further damage.

2. Overheating of the Aircon Capacitor

Another common problem with aircon capacitors is overheating. Overheating can occur when the capacitor is working under stress for an extended period or when the air conditioning unit is overused. Excessive heat causes the internal components of the capacitor to break down, resulting in a failure. The overheating can also be caused by poor ventilation around the capacitor, damaged wiring, or incorrect capacitor sizing.

If your aircon capacitor is overheating, you might notice that the air conditioner is not functioning properly, and the unit may even shut down completely after a short period of operation. To address overheating, the first step is to check the airflow around the aircon capacitor. Ensure that the air conditioning unit is clean and free from obstructions. If the issue persists, replacing the overheated capacitor with a properly sized replacement is necessary.

3. Capacitor Under-Voltage or Over-Voltage

Aircon capacitors can also experience issues related to voltage imbalances. If the voltage supplied to the capacitor is either too low (under-voltage) or too high (over-voltage), it can cause the capacitor to fail. Under-voltage can prevent the capacitor from starting the motor, while over-voltage can cause it to overheat and burn out.

Voltage fluctuations can occur due to problems with the electrical supply, power surges, or issues within the air conditioning unit itself. To fix this issue, it is essential to first determine the cause of the voltage fluctuations. Installing a voltage regulator or stabilizer can help maintain a consistent voltage level, protecting the aircon capacitor from damage. If the capacitor has already failed due to these issues, replacing it with the correct voltage rating is necessary.

4. Capacitor Leakage

Leakage is another frequent problem that can occur with aircon capacitors. When the capacitor is damaged or old, it can develop a leak, typically in the form of an electrolyte leakage. This often occurs with electrolytic capacitors, which are commonly found in air conditioning systems. When this happens, the capacitor may swell, leak, or even explode in severe cases.

A leaking aircon capacitor can cause the air conditioner to stop functioning correctly, and if not addressed, it may result in further damage to the system. The solution to this problem is to replace the leaking capacitor as soon as possible. Professional technicians can inspect the capacitor and determine whether it is still serviceable or needs to be replaced.

5. Incorrect Sizing of the Capacitor

If the aircon capacitor is too large or too small for the air conditioning unit, it can cause a variety of performance issues. An oversized capacitor can result in inefficient operation, while an undersized capacitor can lead to starting problems and even motor failure. It is crucial to ensure that the capacitor is properly sized according to the specifications of the air conditioning unit.

If you suspect that your aircon capacitor is incorrectly sized, it is best to have a professional HVAC technician evaluate your aircon unit and replace the capacitor with one that is properly matched to the system’s requirements. Incorrect capacitor sizing is a common cause of air conditioning problems, but the issue is easy to resolve with the right replacement part.

6. Dirty or Corroded Terminals

The terminals of an aircon capacitor can accumulate dirt, dust, and debris over time, which can hinder the flow of electricity and cause a malfunction. Corrosion can also occur, particularly in areas with high humidity or moisture, leading to poor electrical contact and eventually, capacitor failure.

Cleaning the terminals of the aircon capacitor and checking for any signs of corrosion can help prevent this issue. If the corrosion is severe, the capacitor should be replaced to ensure that the air conditioning unit operates efficiently. Regular maintenance and cleaning of the air conditioning system can help prevent terminal issues from developing in the first place.

7. Capacitor Damage from Power Surges

Power surges, often caused by lightning strikes or electrical storms, can cause significant damage to an aircon capacitor. A power surge can overwhelm the capacitor’s ability to store electrical charge, leading to immediate failure. In some cases, the capacitor may even burst or explode due to the excessive voltage.

To protect the aircon capacitor from power surges, consider installing a surge protector or a whole-home surge protector to safeguard the air conditioning unit. If the capacitor has already been damaged due to a power surge, it will need to be replaced. Surge protection is a worthwhile investment to avoid recurrent damage to your system.

8. Capacitor Failure from Short Circuits

Short circuits in the air conditioning system can lead to aircon capacitor failure. A short circuit can cause an electrical overload, damaging the capacitor and preventing it from performing its intended function. This type of failure typically results in the air conditioning unit not starting or running inefficiently.

If you suspect a short circuit is the cause of the aircon capacitor failure, it is crucial to have a professional technician diagnose and repair the electrical issues within the system. Once the short circuit is repaired, the damaged capacitor can be replaced to restore the functionality of the air conditioning unit.

The aircon capacitor is a vital component in an air conditioning system, and its failure can lead to significant issues with your cooling system. Understanding the common problems associated with capacitors—such as ageing, overheating, voltage imbalances, leakage, and incorrect sizing—can help you identify potential issues early on.