Question

Why do we need to replace our AC capacitor regularly? What's wrong with it after some time? Is there some way to check if it's still good before buying a new one for replacement?

Answer 1

The AC capacitor is an essential component in an air conditioning system that stores and releases electrical energy to help start the compressor and fan motors. Over time, capacitors can degrade and become less effective due to various factors, such as voltage fluctuations, high operating temperatures, and general wear and tear. There are two main types of capacitors in an AC unit:

1. Start Capacitor: This capacitor provides the extra voltage necessary to start the compressor motor. Once the motor starts running, the capacitor is taken out of the circuit by a relay.

2. Run Capacitor: The run capacitor is continuously in the circuit while the AC is running, providing a steady electrical phase to keep the compressor and fan motors running smoothly.

Here are some reasons why capacitors may need replacement:

1. Age: Capacitors have a limited lifespan, typically ranging from 5 to 15 years, depending on the quality and usage. After this period, they are more prone to failure.

2. Heat: AC capacitors are subject to high temperatures when operating, which can cause the electrical components inside to deteriorate over time.

3. Electrical stress: Voltage fluctuations or power surges can weaken the capacitor, reducing its efficiency.

4. Manufacturing defects: In some cases, capacitors may have manufacturing defects that can lead to premature failure.

If you suspect that your AC capacitor might be faulty, there are a few ways to check before buying a replacement:

1. Visual inspection: Look for signs of physical damage, such as bulging or leaking, on the capacitor. These are indications that it has failed and needs to be replaced.

2. Capacitor tester: A multimeter with a capacitance testing function can be used to check the capacitor's capacitance. If the reading is significantly lower than the rated capacitance, the capacitor is likely faulty.

3. Listen for unusual sounds: If the AC is making humming or clicking noises when you turn it on, it could be a sign of a faulty capacitor.

4. AC not starting: If your AC is not starting or having trouble starting, it could be due to a failed start capacitor.

Keep in mind that capacitors store electrical energy even when disconnected from the power source. If you are unsure about how to check the capacitor yourself, it's best to seek assistance from a qualified HVAC technician. They can diagnose the issue and replace the capacitor if necessary to ensure your AC system functions properly.