When it comes to pressure switch for air compressor, you can guess this is an industrial device with a switch function. In most of the pneumatic or hydraulic systems, from small capacity and simple design to large size and complex structure, this equipment is installed and used widely.

However, it’s so difficult for beginners to learn about the pressure switch and how it works. So we want to bring useful information about this device for you to know how to use it properly.

First of all, we have a question you may want to ask about this device.

How Does A Pressure Switch Work On Air Compressor?

Pressure Switch Work On Air CompressorFor the principle of the pressure switch, you can understand as follows:

  • Once the high pressure is on the port of pressure, there are a series of influencing factors. The diaphragm begins to bend and push up the plate of pressure.
  • In case the pressure for the sheet is high to squeeze the spring, the plate of pressure starts to increase. When the force is large enough, the plate of pressure begins to increase till the contacts are connected.
  • Then the circuit is closed for power supply. After that, the sensor movement changes the places of electrical contacts inside the pressure switch to trigger a signal of electricity.

Besides, the scheme is responsible for performing the deflection mechanism connected with a plate of pressure. If the pressure is low, the device has not enough power to press the spring, so the circuit continues to open. So, you need a pressure switch here to control the operation.

Manufacturers often use pressure switches in the form of Manual Reset. These pressure switches may be connected to create or stop a circuit or to open and close a switch when not activated.

Best Air Compressor

How Do You Know If The Pressure Switch Is Bad On An Air Compressor?

When Your Air Compressor Cannot Disconnect Itself

Air Compressor Cannot Disconnect ItselfThe cause may come from a faulty pressure switch. Meanwhile, the machine automatically operates continuously, and it makes a large amount of power consumption and wastes high costs. In the long term, it can reduce the life of the machine.

You need to check the pressure switch at the electrical box on the machine. You use a screwdriver to spin the pressure switch anticlockwise until the device disconnects itself. The pressure switch can also be moved, creating poor contact. You should replace the new one if the equipment quality is low.

When Overloaded Compressors Occur

It may be because the idle mode settings are too high. It usually happens with air compressors that use mechanical pressure switches.

If the applied pressure is too high, the motor will generate too much heat to push up the pressure. You should check the settings of the pressure switch and adjust it.

Your Air Compressor Does Not Run

Air Compressor Does Not RunYou press the button to start the compressor, but nothing happens. Check if the pressure switch protecting the air compressor is jumping and reset it.

Remember to set the pressure switch of the air compressor following the manufacturer’s regulations. Do not try to set a pressure higher than the manufacturer’s recommended level.

If not, the machine can still operate normally at first, but after a while, it will seriously affect the engine and the life of the device.

For example, for an air compressor with a maximum pressure of 8 bar, you should only adjust the pressure to less than or equal to 8 bar. If your compressed air system needs to use a higher pressure than that, it is better to calculate it from the beginning to buy a compressor that suits the needs of the system.

How Do You Test Pressure Switch For Air Compressor?

Test Pressure Switch For Air CompressorThe main problem with the pressure switch is changing the setting value, or the internal electrical switch is not well connected. It is a mechanical switch, so it will easily be worn.

Then how to test this device?

It is easy to accurately check the operating status of the pressure switch when the machine is running with a thermometer.

Most of the time, you can hear the “click” sound when opening and closing the device. You can check pressure at the open or close pressure switch point.

If the pressure is closed, try to adjust it. If this doesn’t work, replace it now.

Another problem is a loose connection. In this case, the pressure switch opens and closes correctly, you can hear a “click” sound, but there is no electrical connection.

You can check with a thermometer. However, please be careful because the pressure switch turns on directly with high voltage (110 volts or 220 volts).

How Do You Adjust The Pressure Switch On Your Air Compressor?

The way of adjusting the pressure switch of the air compressor is very important because it ensures the compressor system operates stably and persistently. Knowing the technique of adjusting the pressure switch appropriately, you will significantly reduce operating risks as well as save a lot of repair costs.

When do you need to adjust the air compressor pressure switch?

adjust the air compressor pressure switch

  • When starting to use the air compressor
  • When changing the equipment used with compressed air, there is a different requirement of working pressure compared to the old air compressor.
  • When problems arise, the air pressure may be uneven or do not meet the requirements of use.

How To Do

How To DoFor small air compressors, the pressure switch controller will be installed on the pressure switch set, while for large-sized screw air compressors, the pressure regulator is located on the control panel of the machine.

First of all, you can adjust the air compressor pressure switch to suit your needs. When deciding which pressure is best for you and your air compressor, you need to remember to set the lowest possible pressure for your compressed application.

You should know that most air compressors have the 7 bar of pressure range, and it is installed when you purchase the machine. But if you want 4 or 5 bars, it’s the best way to lower the installation pressure down.

When you increase pressure, it will raise the electricity costs. If you have a large air compressor of 37kW or more, you can save a lot of money because the annual cost of electricity consumption drops when you set lower air pressure.

With small air compressors, the savings will be less. However, if you can save cost for your family, why don’t you try?

For The Cut-in Pressure

  • You start with the empty gas tank. You switch on the compressor and allow it to run until the cut-out pressure is reached.
  • You open an air release valve slowly to let air escape, then see how the pressure drops. Next, you wait until the machine boots up, record the pressure. It is the cut-in pressure.
  • You then adjust the cut-in pressure with the setting screw by turning clockwise to cut-out pressure. Lastly, you close the air valve. The air compressor will operate until the cut-out pressure is reached.

At this time, you repeat the cycle until you get the correct cut-in pressure setting. You open a release valve slowly to let the compressed air out and wait until the air compressor starts up.

After that, you record the pressure at the starting point (cut-in pressure) and adjust as needed. After this procedure, you have successfully set the cut-in pressure.

For The Cut-out Pressure

  • You can do this process in the same way as the cut-in pressure setting. Now just screw it in the differential pressure mode.
  • If you do not have this screw, you will see a pressure switch with a fixed type of adjustment. Remember to record the pressure when the machine last stops and watch it run again.
  • Next, you adjust the pressure difference according to your needs by turning it clockwise to increase (if you want a higher maximum pressure) or turning counterclockwise to decrease (if you wish to the lower maximum pressure).
  • Then, you open the air release valve, wait until the pressure drop is low enough to start the compressor, and close the valve.
  • Lastly, you wait until the compressor is in use and check the cut-out pressure. Like the cut-in pressure setting process, you repeat these actions to find the correct cut-out pressure.


You need to pay attention to set the cut-in pressure before cut-out pressure. You should also read the user manual because the procedure may vary depending on the type of pressure switch of your air compressor.

Furthermore, some pressure switches can only be adjusted under pressure. You don’t tighten any screws when there is no pressure in the tank or when you just remove the new pressure switch from the package.

The tip for you is that most factories install pressure switches at a cut-in pressure of 6 bar with a pressure difference of 1 bar so that the cut-out pressure is 7 bar.

Final Thoughts

We hope the above sharing on how to use pressure switches and the principle of pressure switches can help you to understand the pressure switch for air compressor. You can select and use it safely now without the need for professionals.

Moreover, when you know how to use and adjust the pressure switch for air compressor, you can help the compressor system to operate stably, sustainably, and save quite a lot of electricity and running costs.

If you have any questions, do not hesitate to leave here. We are willing to answer and discuss more the pressure switch for air compressor with you, guys.