How to Diagnose and Repair an Aircon Capacitor?

When the domestic aircon suddenly becomes inefficient or stops working, in most cases, the homeowners need to repair an aircon capacitor. The aircon is a basic need for the hot summer days, and everybody wants it in the room.

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A faulty capacitor worries homeowners who need in-depth knowledge about the internal components of the aircon. It is easy to understand that it is a component in the electrical circuit of the aircon that is crucial in starting and smoothly running the aircon.

What is a Capacitor, and Why is it Needed?

A capacitor is a small cylindrical device that provides the initial boost to start the aircon. Once the aircon starts, it keeps providing power; therefore, it is usually a start-and-run capacitor. The aircon capacitor is crucial in working the compressor motor because the motor cannot self-start at a single-phase supply without the phase shift provided by the capacitor.

When we install the capacitor, the single-phase supply becomes a two-phase supply, providing enough initial push to start the motor. The capacitor is a tiny component of the overall aircon system. However, the aircon cannot start properly if this capacitor fails to work.

Diagnosis of Aircon Capacitor

Homeowners must know how to check the working of the aircon capacitor; if you do not know, here is how you can check.

Start the aircon, and observe its working; if it does not start immediately, starts with a humming noise, or turns off on its own, you need to repair the AC capacitor. Once you diagnose this issue, you must promptly repair an aircon capacitor to avoid further damage.

Repair Air Conditioner Capacitor

This section explains how to repair an aircon capacitor. The following instructions will help you complete the process without any professional assistance.

1. Power off the Input Supply

Before initiating the replacement, or the repair work, remember you are playing with equipment connected with 220 v supply, and any negligence can cost big time. Therefore, it is wise to ensure that the input supply breaker is turned off and there is no input power to the aircon.

2. Remove the Access Panel

Countercheck the input supply; if it is off, you need to remove the access panel. This removal of the access panel is the first step in the process.

3. Inspect and Check the Capacitor

First, you need to locate the capacitor in the main circuit of the aircon. You will find a cylindrical device connected to the main circuit, the aircon capacitor. Inspect the capacitor physically for any burning or physical damage.

If the capacitor looks good physically, you must check the continuity through the digital multimeter (DMM). If everything looks fine and DMM is showing some value across the capacitor, the capacitor is in good condition; else, you need to remove the capacitor.

Repair an Aircon Capacitor

4. Remove and Discharge the Capacitor

Once you conclude the aircon capacitor is faulty, you need to remove it from the circuit. However, it is important to note that the capacitor stores electrical energy as an electric field and discharges when the external circuit is completed or a load is applied. Therefore, you can get shocked by the capacitor even if the main supply is off.

Remove the capacitor without touching it. Before removing the capacitor, take a clean snap of the capacitor connections. It would help if you discharged the capacitor to drain the stored electrical energy it has stored previously. You can discharge the capacitor by connecting a resistor across its terminals.

5. Get a New Capacitor

When you discharge the old capacitor, take it with you to find a new one of the same rating. Get a new capacitor of the same rating from an electrical components shop. Using the connection’s snap, connect the new capacitor in place.

6. Turn On the Condenser

Now you can turn the condenser on and have a test drive of the new capacitor. If the aircon starts normally, and you do not observe any unwanted or humming noise, you have successfully replaced the aircon capacitor. If the aircon does not start, it is better to call a professional for technical assistance.


It is tricky to repair an aircon capacitor because it is connected to the electrical circuit and can store electrical energy, making you feel a shock even if the main supply is turned off. Therefore, the replacement process is crucial, and one needs to know the replacement process to initiate the process.

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