Why Air Compressor Will Not Build Pressure – Learn How to Fix It

Air Compressor Pressure Gauge Showing Pressure

Usually, your air compressor will not build pressure if there is something wrong with the pump.

But there is another reason that you must not overlook. If there are major leaks in your compressor, your air compressor may get slow to build pressure as well.

To know how the pump and the leaks are responsible for such a problem and how you can fix this, stick with me to the end of this article.

Reasons Why Air Compressor Will Not Build Pressure

An air compressor will not build pressure either because of the pump or because of any leakage.

Problems That Occur in the Pump

Your air compressor will not build enough pressure if the pump has problems. There are mainly 3 problems that I have identified. These are –

The Pump Is Not Properly Connected to the Intake Valve

The intake valve allows air to go inside the pump and blocks air to come out in the reversed direction. But when the valve is not properly sealed with the pump, air will eventually leak from there. When the pump lacks sufficient air it cannot provide the pressure that you require.

The Piston Rings of the Pump Have Issues

In the pump of an air compressor, there are pistons inside. On the pistons, there are piston rings that block air leakage from the piston area. If the piston ring has problems, then air will leak from the pump. Hence the pump won’t be able to provide sufficient pressure.

Pump Gaskets Have Problem

Different pumps have different numbers of gaskets. Some have one, some have two and some have a lot more than that. To understand how gaskets work, here is a small thing you should know first.

Inside the pump, there are two parts. One part of the pump keeps low-pressure air which gets inside through the intake valve. The other part keeps high-pressure air which goes to the tank from the pump.

A gasket keeps this low pressure and high-pressure air separated in the pump. When there is a problem with the gasket, it cannot keep the airs separated. For this reason, high-pressure air cannot go inside the tank. Hence, the compressor fails to build pressure.

Problems Due to Leaks

So far, you have seen how the pump is responsible for an air compressor to not build enough pressure. Now let’s find out why leaks are also responsible.

Leaks in the Pressure Switch

The pressure switch allows a compressor to run at a certain range of pressure. When the pressure reaches to cut out pressure the pressure switch turns the compressor off. It turns the compressor on again when the pressure reaches to cut-in pressure.

If the pressure switch leaks, then the pressure level never reaches the cut out pressure or it takes a long time to reach that pressure. So, you keep the compressor on for a long time and still, you don’t get enough pressure.

Leaks in the Tank

When there are major leaks in the tank, there will not be enough air inside to provide sufficient pressure. Possible reasons for a tank to leak air are:

  • When the tank is really old.
  • If the tank is made of low-quality material.
  • The hose is not properly connected to the tank.

Leaks in the Check Valve

Aside from the tank, there can also be leaks in the check valve that causes air to escape. A check valve allows air to go out with a certain pressure level. It stops air to come back in. However, when the disc of the check valve gets cracked, air leaks from the check valve.

How to Fix an Air Compressor Slow to Build Pressure

As annoying as this problem is, there are some simple steps that you can follow to get rid of this problem. The steps are –

Check if the Valves Are Functioning Properly

Whether it is the intake valve or the check valve, check all the valves thoroughly to see if there is an air leak or not.

When the valves are not functioning properly, air will definitely leak from there and it will cause the pressure to fall.

You should also check if the valves are properly tightened with the tank or the pump. Loose connection often leads to air leak which then drops the pressure.

Look Out for Leaks in Different Parts and Fix Them

There are mainly two reasons for an air compressor to leak.

  • If the connections are loose.
  • If there are holes on any part.

As I have said earlier, if there is a loose joint, the air will leak. So there is nothing more to say about that.

On the other hand, if there is any hole on any part of the compressor, you have to find that out and fix it. You can check out our article on air compressor leaking air to learn more about this.

Clean the Filters

In the compressor, if you have dirty filters, air will get blocked while flowing through the components. Blocked air will cause less pressure to build up in the tank. Because the blockage won’t allow sufficient air to flow into the tank.

However, when there is not enough pressure in the tank, a little to no air will be coming out from the compressor. So, it is highly recommended that you clean the filters properly.

Do a Pump Test to Find Leaks or Any Other Problems

To find out if it is a leakage problem or if there is any problem with the pump, you can do a quick pump test. To do so, follow these steps –

  • First of all, empty the tank by draining all air out.
  • Then close the outlet of the tank so that air can only go in.
  • Then set your desired cut in and cut out pressure in the pressure switch.
  • Now, start the compressor and record the time it takes to fill the tank.
  • When it reaches the cut-out pressure, the compressor will automatically stop.

After you are done with this test, if there is any leakage, you can easily identify it by following our guide as I have said earlier. And if you don’t find any leakage, then look in the pump and see if there is any problem there.

If you find pump problems, it should be one of the above-given problems. You can get rid of these problems by –

  • Properly connecting the intake valve.
  • Changing the piston ring if there is any problem
  • Replacing the gaskets if the gaskets are damaged.

Frequently Asked Questions

How do I increase air pressure in my air compressor?

Follow these steps to increase the air pressure in your compressor.

  • Empty the tank and run the compressor till it reaches the cut-out pressure.
  • Open a drain valve and let a little air out.
  • Now, wait for the compressor to start again.
  • Next, set up a new cut in pressure level.
  • Finally shut off the drain valve.

By doing so, you will see how the pressure increases in your compressor.

How do you use a pressure regulator on an air compressor?

A regulator is used in a compressor to regulate the pressure. That means you can use the pressure regulator to increase or decrease the pressure of your compressor.

To do so, all you need to do is to wait for your compressor to reach the cut-out pressure. After that, turn the regulator right and you will see that the pressure is increasing. Turn it left to decrease the pressure.

Does a pressure regulator reduce flow?

In a static system, where the flow is unchanged, a pressure regulator cannot reduce the flow of air. However, when it comes to a compressor, there is an option to control the flow with the pressure regulator.

So, here you can use the pressure regulator to reduce the flow. But you have to keep in mind that the air compressor will not build pressure if you reduce the flow too much.

1 thought on “Why Air Compressor Will Not Build Pressure – Learn How to Fix It”

  1. we using G 132w air compressor is not building pressure. i do first filter clean and fixing and run then air pressure building is very well in more then 8hrs than again same problem came what can i do pls teach me

    Mechanical Technician


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