why does contactor on ac keep going out


Why does Contactor on AC keep going out

Are you tired of the constant frustration of your AC's contactor going out? It's a common problem that many homeowners face, but fortunately, there are solutions available. In this article, we will explore the reasons behind why the contactor on your AC keeps going out and discuss possible fixes to prevent this issue from recurring. By understanding the underlying causes and implementing the appropriate measures, you can enjoy cool air without the hassle of a faulty contactor.

Understanding the Contactor

Before we delve into the reasons why a contactor on an AC may keep going out, let's first understand what a contactor is and what it does. The contactor is an electrical switch that controls the flow of current to the compressor and condenser fan in your air conditioning unit. When the thermostat calls for cooling, the contactor allows electricity to flow, activating the compressor and fan. Without a functioning contactor, your AC system will not be able to cool your home effectively.

1. Poor Electrical Connections

One of the most common reasons why a contactor on an AC keeps going out is poor electrical connections. Over time, the terminals on the contactor can become loose or corroded, impeding smooth electrical flow. Additionally, wires may become frayed or damaged, further exacerbating the problem. When the electrical connections are compromised, the contactor may fail to engage or disengage properly, leading to frequent burnouts.

To address this issue, it is crucial to regularly inspect and maintain the electrical connections on your AC's contactor. Start by turning off the power to the unit and removing the access panel. Carefully examine the terminals for signs of corrosion, such as a greenish residue. If present, clean the terminals using a wire brush and apply an anti-corrosion solution. Next, inspect the wires for any damage and replace them if necessary. Ensuring secure and clean connections will help prevent the contactor from going out prematurely.

2. Voltage Spikes and Power Surges

Another common cause of contactor burnouts is voltage spikes and power surges. These sudden increases in electrical voltage can overload the contactor, resulting in its failure. Voltage spikes can occur due to lightning strikes, utility company issues, or faulty wiring. Power surges, on the other hand, are abrupt increases in voltage that may last a few seconds or minutes. They can be caused by appliances turning on and off, faulty wiring, or even issues with the electrical grid.

To protect your AC's contactor from voltage spikes and power surges, consider installing a surge protector. A surge protector is an electrical device that redirects excess voltage away from your appliances and protects them from damage. It acts as a barrier between the incoming electricity and your AC system, absorbing or redirecting the excess voltage. By installing a surge protector, you can safeguard your contactor and other sensitive electronic components from potential electrical disturbances.

3. Overheating

Overheating is another common reason for contactor failure. AC units generate a significant amount of heat while operating, and if the contactor is exposed to excessive heat for extended periods, it can deteriorate and malfunction. This problem is often more prevalent in areas with high ambient temperatures or insufficient airflow around the unit. Overheating can also be caused by dirty or obstructed condenser coils, clogged air filters, or a malfunctioning fan motor.

To prevent contactor overheating, ensure that your AC unit is properly maintained. Regularly clean or replace air filters to promote adequate airflow. Clear any debris or vegetation around the condenser unit to allow for proper heat dissipation. Inspect the condenser coils for dirt or damage and clean them if necessary. If the fan motor is not functioning correctly, have it repaired or replaced promptly. By addressing these issues, you can help prevent your contactor from burning out due to overheating.

4. Age and Wear

Over time, contactors naturally degrade due to normal wear and tear. The electrical contacts inside the contactor can become pitted, worn, or bent, reducing their ability to make proper contact. As a result, the contactor may experience frequent arcing, leading to burnouts. Additionally, the plastic casing of the contactor can become brittle and prone to cracking, exposing the electrical components to moisture or other contaminants.

If your contactor is old and showing signs of wear, it is advisable to replace it with a new one. Upgrading to a more durable and reliable contactor will provide peace of mind and a more consistent performance. Consult with a professional HVAC technician to determine the right contactor for your AC unit and ensure it is installed correctly.

5. Electrical System Issues

Sometimes, the problem may not lie solely with the contactor itself but with the electrical system supplying power to your AC unit. Issues such as improper wiring, incorrect voltage, or inadequate electrical capacity can also contribute to contactor burnouts. If the electrical system is not properly configured to handle the load, it can put excessive strain on the contactor and other components, leading to premature failure.

If you suspect that your electrical system is causing contactor issues, it is essential to have a qualified electrician inspect and evaluate it. They will be able to identify any wiring or capacity issues and make the necessary adjustments or upgrades. Ensuring that the electrical system is compatible with your AC unit's power requirements will help extend the life of your contactor and enhance the overall performance of your cooling system.


In conclusion, a contactor on an AC that keeps going out can be a frustrating and disruptive issue. However, with a better understanding of the underlying causes and the appropriate preventive measures, you can avoid this problem in the future. Regularly inspect and maintain the electrical connections, protect against voltage spikes and power surges with a surge protector, prevent overheating by practicing proper AC maintenance, consider replacing an old contactor, and address any potential electrical system issues. By implementing these steps, you can enjoy a reliable and efficient AC system with a contactor that remains in good working order. So, bid farewell to the inconvenience of a faulty contactor and embrace the comfort of a consistently functioning air conditioning system.


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