do ac non reversint contactor go bad


Why Do AC Non Reversint Contactors Go Bad?


Air conditioning is a vital component of modern living, providing us comfort and relief during scorching summers. One crucial part of an air conditioning system is the contactor, a device responsible for turning the outdoor unit on and off. However, like any mechanical component, contactors can experience failure over time. In this article, we will delve into the reasons why AC non reversing contactors go bad and explore potential solutions to mitigate these issues.

Understanding AC Contactors and Their Function

AC contactors are electromagnetic switches that control the flow of electricity to the compressor and condenser fan motor in an air conditioning system. These devices are typically located in the outdoor unit and are responsible for starting and stopping the outdoor unit's operation based on the temperature setting on the thermostat.

Common Causes of AC Non Reversint Contactor Failure

Contactors are designed to handle heavy electrical currents, but various factors can contribute to their failure. Let us explore some of the most common causes:

1. Excessive Electrical Load

Air conditioning systems draw a significant amount of electrical current during operation. If the electrical load exceeds the contactor's specified capacity for an extended period, it can lead to contactor failure. This can occur if the system has an undersized contactor or if there is another issue causing the unit to consume excessive power.

2. Age and Wear

Contactors, like most mechanical components, have a limited lifespan. The electrical contacts within the contactor can become worn and pitted over time, leading to reduced efficiency and eventual failure. Furthermore, the plastic housing of the contactor can deteriorate due to prolonged exposure to harsh weather conditions, resulting in cracks or other damage.

3. Electrical Voltage Spikes

Sudden voltage spikes can occur due to electrical storms, power surges, or faults in the electrical supply. These voltage spikes can cause severe damage to sensitive components, including contactors. The sudden surge in electrical current can lead to overheating and welding of the contactor's electrical contacts, rendering it inoperable.

4. Contamination and Corrosion

Outdoor air conditioning units are subject to various environmental factors such as dust, dirt, moisture, and corrosive chemicals. Over time, these contaminants can accumulate on the contactor's electrical contacts and prevent them from making proper electrical connections. Additionally, corrosion can occur due to exposure to moisture, further hindering the contactor's performance.

5. Poor Maintenance

Regular maintenance is crucial for the smooth operation of any mechanical system, including air conditioning units. Failure to perform routine cleaning and inspection can lead to the buildup of dirt, debris, and corrosion on the contactor, reducing its lifespan. Neglecting maintenance can also allow minor problems to go unnoticed, which can eventually result in severe contactor failure.

Signs of a Bad AC Contactor

Identifying a failing or faulty contactor is essential for prompt repair or replacement. Here are a few signs that may indicate a bad AC non reversing contactor:

- Frequent tripping of circuit breakers: If the circuit breaker that supplies power to the outdoor unit trips repeatedly, it could be due to a faulty contactor.

- Hot contactor housing: When a contactor is excessively heated, it may indicate that it is failing to function correctly.

- Buzzing or humming sound: Unusual noises, especially a buzzing or humming sound emanating from the contactor, can indicate worn-out or malfunctioning contacts.

- Outdoor unit not turning on/off consistently: When the outdoor unit fails to start or stop consistently, it may be due to a faulty contactor.

Preventive Measures and Solutions

While contactor failure cannot always be prevented, taking preventive measures and implementing solutions can prolong their lifespan. Here are some steps to mitigate contactor issues:

1. Proper Sizing and Installation

Ensuring that the contactor is correctly sized for the electrical load of the air conditioning system is crucial. Oversized contactors can lead to poor performance, while undersized contactors can experience excessive stress and premature failure. Proper installation following manufacturer guidelines is also vital to avoid any loose connections or other installation-related issues.

2. Regular Cleaning and Maintenance

Cleaning the contactor and its surrounding area regularly can help prevent the buildup of contaminants such as dust, dirt, and debris. It is recommended to inspect the contactor during routine maintenance and clean it using a soft brush or compressed air if necessary. Additionally, addressing any signs of corrosion promptly can extend the contactor's lifespan.

3. Surge Protection

Installing surge protectors can safeguard the air conditioning system from sudden voltage spikes. These surge protectors act as a barrier, preventing excessive voltage from reaching sensitive components like the contactor. Investing in surge protection devices can significantly reduce the risk of contactor failure due to electrical surges.

4. Timely Replacement

Regular inspection of the contactor can help identify signs of wear, pitting, or other damage. If any significant issues or signs of failure are detected, it is essential to replace the contactor promptly. Early intervention can prevent further damage to the system and ensure proper functioning.


AC non reversing contactors are prone to failure due to factors such as excessive electrical load, age, electrical voltage spikes, contamination, and poor maintenance. Identifying the signs of contactor failure and implementing preventive measures such as proper sizing, regular cleaning, surge protection, and timely replacement can help prolong their lifespan. By addressing these issues proactively, homeowners can ensure the smooth functioning of their air conditioning systems and avoid unexpected breakdowns during sweltering summer months.


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