How Do You Adjust The Cut In Pressure Switch?

Are you looking to ensure that your air brakes are functioning at peak performance? Adjusting the Bendix on an air governor is a crucial aspect of maintaining the air brake system of a vehicle. Proper adjustment helps to regulate the pressure and timing of the air compressor, ensuring efficient braking performance and overall safety on the road. In this article, we will provide a step-by-step guide on how to adjust the Bendix on an air governor, offering practical advice and expert tips for achieving optimal functionality. Whether you’re a commercial truck driver, a fleet manager, or an automotive enthusiast, understanding this process is essential for keeping your air brake system in top condition. Follow our instructions to learn how to adjust the Bendix on an air governor and maintain the safety and reliability of your vehicle’s braking system.

Key Takeaway
To adjust the Bendix on an air governor, start by releasing the air pressure in the system. Then use a wrench to turn the adjusting screw clockwise to increase the cut-out pressure or counterclockwise to decrease it. Check the pressure using a gauge and continue adjusting as needed until the desired pressure is reached. Finally, re-pressurize the system and check for proper operation. Always consult the manufacturer’s guidelines and follow proper safety precautions when working with air brake systems.

Understanding the Pressure Switch

The pressure switch is an essential component in controlling the operation of a variety of systems, including water pumps, air compressors, and HVAC units. It works by monitoring the pressure within the system and activating or deactivating the power supply to the pump or compressor based on preset pressure settings.

When the pressure in the system reaches the cut-in pressure setting, the switch closes the circuit to start the pump or compressor. As the pressure increases, it eventually reaches the cut-out setting, causing the switch to open the circuit and stop the pump or compressor. This cycle continues as the pressure fluctuates within the designated range.

Understanding the pressure switch involves knowing how to adjust the cut-in and cut-out pressure settings to ensure proper operation of the system. The cut-in pressure setting determines the lower limit at which the switch allows the system to start, while the cut-out pressure setting designates the upper limit at which the system stops. By adjusting these settings, users can fine-tune the performance of their equipment to meet specific requirements and prevent unnecessary cycling.

Identifying the Cut-In Pressure

When it comes to adjusting the cut-in pressure switch, the first step is identifying the cut-in pressure. This pressure level determines when the compressor should start working to pressurize the air tank. To identify the cut-in pressure, you will need a pressure gauge and a basic understanding of how the pressure switch works.

Start by locating the pressure switch on your compressor. It is typically a square or rectangular device with a plastic cover and electrical connections. Once you have found the pressure switch, locate the two small adjustment screws on the top or side of the switch. One of these screws controls the cut-in pressure, while the other controls the cut-out pressure.

To identify the cut-in pressure, you need to attach the pressure gauge to the air tank’s fitting. With the compressor off, the gauge will display the current pressure in the tank. This is the cut-in pressure level that should trigger the compressor to start working. You can then adjust the pressure switch as needed to ensure it aligns with the recommended cut-in pressure for your specific compressor model.

By identifying the cut-in pressure and ensuring it is set correctly, you can optimize the performance and efficiency of your compressor while minimizing wear and tear on the system.

Determining the Cut-Out Pressure

When determining the cut-out pressure for a pressure switch, it’s essential to understand the specific requirements of the equipment or system it is connected to. The cut-out pressure refers to the pressure level at which the switch is designed to stop the operation of the system or equipment in order to prevent over pressurization. This cut-out pressure is a crucial parameter that needs to be carefully determined and set for proper functioning.

To determine the ideal cut-out pressure, it is important to refer to the manufacturer’s guidelines and specifications for the particular pressure switch being used. These guidelines typically provide the recommended cut-out pressure range suitable for the specific application. It’s important to adhere to these recommendations to ensure the optimal performance and longevity of the equipment.

Additionally, conducting a thorough assessment of the equipment’s requirements and the system’s operational needs is essential. Factors such as the maximum pressure capacity of the equipment and the desired operational pressure range should be taken into consideration when determining the cut-out pressure. This assessment ensures that the cut-out pressure is set at a level that best supports the efficient and safe operation of the system or equipment.

Lastly, conducting tests and monitoring the system’s performance under varying pressure conditions can help in fine-tuning the cut-out pressure. This allows for adjustments to be made as needed to ensure that the system operates within the specified pressure parameters, maximizing its effectiveness and safety.

Locating the Adjustment Screws

Locating the Adjustment Screws

When adjusting the cut-in pressure switch, it’s important to locate the adjustment screws first. These are typically found on the pressure switch itself. The cut-in pressure screw is often labeled as “Differential” or “Diff,” while the cut-out pressure screw is labeled “Range” or “R.” The location and labeling of these screws may vary depending on the specific model and brand of pressure switch, but they are generally situated next to the contacts and terminals on the pressure switch.

Before attempting to locate the adjustment screws, it’s crucial to turn off the power supply to the pressure switch and any connected equipment. This will ensure safety during the adjustment process. Once the power is turned off, you can remove the protective cover on the pressure switch to access the adjustment screws. Some models may have a protective cover that can be easily removed by hand, while others may require the use of a screwdriver.

After removing the cover, take a moment to familiarize yourself with the layout and components of the pressure switch. The adjustment screws are typically small and may require a screwdriver to turn. It’s important to carefully inspect the pressure switch to ensure that you have identified the correct screws for adjusting the cut-in and cut-out pressures. Familiarizing yourself with the position and function of these adjustment screws is essential before proceeding with any adjustments to the pressure settings.

Adjusting the Cut-In Pressure

To adjust the cut-in pressure on a pressure switch, start by disconnecting the power supply to the switch to ensure safety. Next, identify the cut-in pressure adjustment screw, usually located on the side of the switch. Use a screwdriver to turn the screw in a clockwise direction to increase the cut-in pressure or counterclockwise to decrease it.

Before making any adjustments, carefully read the manufacturer’s instructions as different pressure switches may have specific guidelines. It’s crucial to make small adjustments and then test the switch to ensure it’s functioning correctly. Utilize a pressure gauge to monitor the pressure levels as you make adjustments.

After making the necessary adjustments, reconnect the power supply and observe the pressure switch operation for any irregularities. It’s important to ensure that the cut-in pressure is set within the recommended range for the specific application. When adjusting the cut-in pressure, always prioritize safety and follow the manufacturer’s guidelines to avoid potential damage to the equipment or system.

Adjusting the Cut-Out Pressure

To adjust the cut-out pressure of a pressure switch, start by identifying the location of the cut-out pressure adjustment screw, often found near the top of the pressure switch. Turn off the power supply to the switch and release any pressure in the system before attempting any adjustments. You can accomplish this by draining the compressed air from the tank or system the pressure switch is controlling.

Next, use a screwdriver to turn the cut-out pressure adjustment screw clockwise to increase the cut-out pressure or counterclockwise to decrease it. It’s important to make small adjustments and then test the pressure to ensure it reaches the desired cut-out pressure. Be cautious not to over-tighten or loosen the adjustment screw too much, as this can affect the switch’s performance and safety.

Once you have made the necessary adjustments, turn the power supply back on and monitor the pressure switch to ensure it functions properly at the newly set cut-out pressure. It’s important to refer to the manufacturer’s guide for specific instructions on adjusting the cut-out pressure, as different pressure switches may have varying adjustment procedures.

Testing the Pressure Switch

To test the pressure switch, you will need a pressure gauge and a multimeter. Start by disconnecting the power supply to the pressure switch to ensure safety. Next, locate the pressure switch and carefully remove the cover. Once the cover is removed, use a pressure gauge to measure the actual pressure in the system. Compare this reading to the pressure setting recommended by the manufacturer. If the pressure does not match, it may be necessary to calibrate the switch.

You can use a multimeter to test the electrical continuity of the pressure switch. With the power supply still disconnected, carefully remove the electrical connections to the pressure switch. Set the multimeter to measure resistance and attach the probes to the terminals of the pressure switch. If there is no continuity or the resistance is not within the specified range, the pressure switch may need to be replaced.

After performing these tests, you can determine if the pressure switch is functioning properly or if it needs adjustment or replacement. It is important to follow the manufacturer’s guidelines and recommendations for testing and adjusting the pressure switch to ensure safe and efficient operation of the system.

Troubleshooting Common Issues

When troubleshooting common issues with a pressure switch, it’s important to address any inconsistent cut-in and cut-out pressures. This can be caused by a variety of factors, including a malfunctioning pressure switch, incorrect pressure settings, or a faulty pressure tank. First, check that the pressure switch is properly installed and the wires are connected securely. Ensure that the pressure settings are appropriate for the system and adjust if necessary.

Another common issue is a pressure switch that continuously cycles on and off. This can indicate a problem with the pressure tank, such as water logging or a pre-charged tank that needs adjustment. Inspect the pressure tank and re-pressurize as needed, or consider replacing the tank if it’s damaged or malfunctioning.

Additionally, if the pressure switch fails to turn on at all, it could be due to a faulty electrical connection or a defective pressure switch. Verify that the electrical connections are secure and inspect for any damaged wires or components. If there are no visible issues, consider replacing the pressure switch to restore proper functionality.

When experiencing common issues with a pressure switch, it’s essential to address the root cause of the problem promptly to prevent further damage to the system and ensure reliable operation. Regular maintenance and inspection of the pressure switch and associated components can also help to prevent potential issues from arising.


Adjusting the cut-in pressure switch is an essential task for maintaining optimal performance and efficiency in a variety of systems, from water pumps to air compressors. By properly adjusting the cut-in pressure, you can ensure that the system operates at the desired pressure levels, preventing equipment damage and maximizing energy savings. Understanding the correct procedures for adjusting the cut-in pressure switch is crucial for anyone responsible for the maintenance and operation of these systems.

In conclusion, mastering the process of adjusting the cut-in pressure switch is a valuable skill for ensuring the smooth and efficient operation of various systems. It allows for precise control over pressure levels, promotes equipment longevity, and helps to conserve energy. By following the recommended guidelines and procedures, individuals can confidently make necessary adjustments to the cut-in pressure switch, ultimately leading to improved system performance and longevity.

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