Changed Capacitor AC Still Not Working | Identifying and Resolving the Root Cause

A failed capacitor is the most common cause of an AC not working. An Air Conditioner Unit may have capacitors in it. These capacitors are used to store energy and provide it to the AC fan and compressor motor upon start-up and when running. An AC will stop working due to a faulty capacitor.

If the AC still doesn’t work after the faulty capacitor is replaced it indicates that the AC has other failed components other than the capacitor. Other commonly failed components are the compressor, fan, blower, etc. all these components have an electric motor. So, the cause of failure can be boiled down to a failed motor too.

Why is AC Still Not Working after Changing the Capacitor?

An Air condition unit has several vital components like the compressor, fan, blower, etc. that operate using an electric motor. And motors require capacitors to start up and keep running. So, most AC failures are due to a failed capacitor. 

If the AC still doesn’t work after replacing the capacitor, the other possible causes of failure are the compressor, fan, or the blower motor not working. It may also indicate an electrical system failure, blown fuse, faulty thermostat, or clogged air filter.

1. Damaged Motor

The AC compressor, fan, and blower have electric motors in them. These motors may be damaged due to the faulty capacitor. Using an ohm meter check for continuity in the motor coils. If discontinuity is found it indicates that the motor is faulty.

2. Blown Fuse

Check the fuse of the AC using a multimeter or ohm meter. If the multimeter doesn’t show continuity between the two terminals or the ohm meter shows infinite resistance then the fuse is blown. Replace it with a good fuse.

3. Faulty Thermostat

If the AC thermostat is not working properly, the air conditioner may continuously cycle on and off or fail to work at all. Reset the thermostat. If it doesn’t resolve the problem, replace the thermostat with a known good one to see if it is the cause of the problem.

4. Damaged Electronics 

An air conditioner has several electronic circuits that control the different components of the AC. If any electronic component is damaged then the AC will not function. It is generally rare but happens nonetheless. Professional assistance is required to resolve this issue.

5. Clogged Air Filter

Dirty or clogged up air filters or obstructed ducts can cause airflow problems in the AC causing a frozen coil. Periodically clean or replace the air filter and keep the ductwork clean to prevent a frozen coil. Also, make sure that the AC has proper ventilation and air supply.

Procedure to Change an AC Capacitor

Changing an AC capacitor is a common maintenance task that can help restore your air conditioning unit’s efficiency. Here’s a step-by-step guide on how to change an AC capacitor:

Step #1: Safety First

Before you begin, prioritize safety. Turn off the power to your AC unit by switching off the circuit breaker or disconnecting the power source. Always use appropriate safety gear, such as gloves and safety glasses, when working with electrical components.

Step #2: Locate the Capacitor

The capacitor is typically a cylindrical or oval-shaped component located inside the AC unit. It stores and releases electrical energy to start the compressor and fan motors.

Step #3: Discharge the Capacitor

Even after disconnecting the power, capacitors can still hold a charge, which can be dangerous. To discharge the capacitor, use a screwdriver with an insulated handle to bridge the terminals of the capacitor, effectively short-circuiting it. Ensure there’s no charge by using a voltmeter.

Step #4: Disconnect Wires

Carefully take note of the wires connected to the capacitor and their positions. Use a pair of needle-nose pliers to disconnect the wires from the terminals. Label the wires if necessary to avoid confusion during reinstallation.

Step #5: Remove the Old Capacitor

The capacitor is typically held in place by a metal or plastic strap. Loosen the strap or mounting bracket and remove the old capacitor. Take note of the capacitor’s specifications, including its microfarad (μF) rating and voltage.

Step #6: Install the New Capacitor

Install the new capacitor, ensuring it matches the specifications of the old one. Attach it securely to the mounting bracket. Connect the wires to the new capacitor, making sure they are in the same positions as before. Use wire nuts or terminal connectors to secure the connections.

Step #7: Test the AC Unit

With the new capacitor in place, turn the power back on at the circuit breaker or reconnect the power source. Start your AC unit and observe its performance. Check for proper cooling and listen for unusual sounds. If everything is functioning as expected, you’ve successfully replaced the capacitor.

Frequently Asked Questions and Answers

Can I Run My AC Without a Capacitor

No, an AC cannot run without a capacitor. The capacitors of the AC are responsible for starting and running the compressor, fan, and blower motors of the AC. Without these capacitors, these components cannot function. So, an AC cannot be run without a capacitor.

Why Does My Air Conditioner Capacitor Keep Going Out

The primary cause of an air conditioner capacitor going out is exposure to excessive heat. Make sure that the AC is kept in the shade and that the air circulation inside the AC is not obstructed. Another cause may be using a 370 VAC capacitor instead of the 440 VAC one for cost-cutting purposes.

What Happens if I Put the Wrong Capacitor in My AC

Putting a wrong capacitor will damage the compressor, fan, or blower motor. The motors are designed to operate with a specific valued capacitor. If a wrong capacitance or voltage capacitor is used instead of the factory one, the motor will fail and may cause a severe electrical accident.

How to know if the capacitor is bad?

The first signs of a faulty capacitor are the AC not blowing any cold air, the compressor making a humming noise, or the capacitor itself making a clicking noise. Or if the capacitor is found to be bulging or any oily substance leaking from it, it surely is faulty. A capacitor tester may also be used to identify a faulty capacitor.

Conclusion

The primary cause of an AC not functioning is a faulty capacitor. If the AC still doesn’t work after changing the capacitor it indicates that the AC has other problems like the compressor or fan motor not working, a blown fuse, a faulty thermostat, a damaged electrical system, etc.