Air Compressor Pressure Switch

For your air compressor to runs properly, it is essential that the air pressure must be under extreme control. The air compressor pressure switch does just that. It determines when your air compressor starts, or stop when the pressures hits a certain limit.

From the mechanic point of view, the air compressor pressure switch, is one of the most important part, among the air compressor accessories. However, it is also the most often prone to break down. In this guide, I will give you insights onto how it works, the settings for it, as well as common air compressure pressure switch type and model.

On updated air compressor model, the pressure switch is automatically run, with the help of a sensor placed within, so it could rightly determine and display the exact pressure on the handy LED screen. On small air compressors or the older version, the pressure switch is purely mechanical. You will set up the lower and upper pressure using the big and small set-screws.

Air Compressor Switch Settings

Determine the right pressure

Calculate the correct amount of pressure to use for your air tools, and keep it as low as possible. Don’t put the pressure just as advertised by the air tools brands, as the higher the pressure, the more energy the machine consumes. Gather it up to a year, the savings in cost for setting the correct air pressure is considerable.

Lower and upper pressure limit

Your air compressor will have a lower and upper pressure limit. If the pressure reaches the upper limit, the machine stops. It will only resume operation once the pressure falls down to the lower limit.

The difference between the lower and the upper pressure limit is call the pressure band, or the pressure differential.

One quick rule is to have the pressure band of minimum 14 PSI. If this figure is set too small, the air compressor will stop and starts very regularly, leads to faster wear out and lower efficiency, as well as damage the pressure switch.

So do it this way:

  1. Find out the minimum PSI your air compressor requires to operate (this is in the manual book)
  2. Set the air compressor switch just a bit above that figure (just to be sure)
  3. Put that amount, plus 14 PSI to get your upper pressure limit

This is for the rule of thumb. For some air compressors, it could be better if the differential band is higher, helping the air compressors to have more time to heat up to get rid of any moisture and water inside.

How to set the pressure switch

Most pressure switch will have the big set-screw to set the lower pressure limit. The smaller set-screw will be used to set the upper pressure limit. Remember this fact when you read the step-by-step below. Also, set the Lower Limit Pressure 1st, the comes the upper limit pressure.

A. Set the lower-limit pressure

  1. Get start with an empty tank and runs it till it reaches the determined upper pressure limit
  2. Let the air goes out and decrease the pressure by open the drain.
  3. It takes some time for the air compressor to start again. When it starts, take note of the pressure – that is the lower pressure limit.
  4. Get the big set-screw to adjust the lower pressure limit.

B. Set the upper limit pressure – just repeat the steps above for the upper limit pressure.

Air Pressure Switch Type & Model

There are a wide range of air compressor pressure switch to choose from, with lots of shapes, styles, or some extra options combined. Belows are some of them:

Pressure switch with on/off settings

These types of switch has an on/off option. If on is chosen, the air compressor will starts and stops according to the set upper and lower pressure limit. This kind is popular among small air compressors. For large compressors, usually the switch will not have the on/off or auto options. Instead, the machine starts and stops with a motor starters.

Pressure switch with mechanical connection

Some switches are attached to the machine using a connection, with the common size of 0.25 inch, 3/8 inch or 1/2 inch.


The air compressor pressure switch is very important, as it controls the pressure at which your machine is running. Due to its constantly working, the pressure switch is highly susceptible to worn out, and break down. Therefore, enough care should be given, with monthly maintenance to ensure it works properly.

Find out more about other Air Compressor Accessoriessuch as the air compressor oil

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