How to drain an air compressor: a step-by-step guide

If you use a compressor, it needs to be properly maintained. It is not enough to simply clean the external parts, and check pressure gauges or valves for defects. It is important to drain the air compressor tank. Read more about how to drain the air compressor in this article.

how to drain an air compressor

Features of water ingress

Before proceeding to study the question of how to drain an air compressor, you should study the principle of water penetration inside. During the use of the compressor, the air is sucked in, so then you get compressed air.

The air contains moisture, or rather, water vapor.

The water vapor then begins to condense into water droplets. They accumulate and then drain. Together with moisture, pollution, and dust that is in the atmosphere are absorbed.

Oil can penetrate inside, which lubricates the seals. Over time, more water starts to accumulate, and the measurement is in gallons.

What happens if water gets into other parts of the compressor?

If the water penetrates further, it can cause several problems. First, water provokes rust.

Because of this, the structure of the device may deteriorate, which may cause the air tank to explode. Water may penetrate the inside of the instruments, due to which they deteriorate.

If water starts to accumulate, it takes up a lot of space. Because of this, the amount of air is reduced. This can cause air to enter the compressor tank. This significantly reduces the efficiency of the device. And the display of the pressure gauge will show incorrect information.

Particles and contaminants that are sucked in with the water can prevent airflow. Because of this, contaminants get inside the air tools, causing them to deteriorate.

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Air compressor tank drain frequency

As you know, water contains many contaminants. In combination with other contaminants and dust, the cocktail causes severe damage to the compressor and pneumatic-type tools. Quite often, people wonder how often it will be necessary to drain water from the air tank of the device.

If you operate your device daily, draining an air compressor should be done every few days. If this is not done, moisture and dust will accumulate. This negatively affects the performance of the device, as well as other pneumatic tools.

If you only use tools intermittently, the drain should be done after every 3-4 uses. If you do not use the compressor for a long time, it is better to empty the air tank beforehand.

This is because water and dirt that accumulate inside the air tank can cause significant damage to pneumatic tools.

Air compressor drain features

You need to understand that draining water from an air compressor is not a very difficult task. In total, several important steps help extend the life of the device and effectively carry out the work. The process can be manual or automatic. Everything will be discussed in more detail below.

Manual drain features

If you plan to do all the work manually, there are a few important steps that need to be followed.

Determining the location of the drain valve

Almost all air compressors have a drain valve at the bottom. Often the air compressor drain valve can be present on the side. Side options are more convenient because they are easier to open and close. However, it is impossible to completely drain the water.

The drain valve, which is on the side, helps to drain the water by air pressure. Until there is such pressure, it is impossible to drain the water. In this case, rust can clog the holes. Therefore, it is better to choose air compressors that have a drain valve at the bottom.

Valve opening

If your drain valve open is on the bottom, water will immediately flow out. Under it, you need to put a tray into which water will drain. This prevents the soiling of the floor.

After that, you need to add water to the air tank to clean it of contaminants.

A compressor tank that is on the side will require air pressure. You have to start the compressor to create air pressure. After a few minutes, it can be turned off. Open the valve and wait until the air completely pushes out the water. Keep a container in which the dirt will drain.

Valve closure

Once the compressor tank is empty, the valve can be closed. You can use thread tape that will be on the drain valve before closing. This prevents leaks.

Checking for leaks is pretty simple. Start the air compressors first, and apply a soapy solution with the drain valve fitting. If the water forms bubbles, you have to turn the valve harder using a wrench. Then repeat the leak test.

If a leak occurs, remove the valve and tighten the threaded tape tightly. Next, check. If this does not solve the leak, the valve needs to be replaced.

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Features of automatic drain

Many refuse to use the manual method because of its laboriousness. Therefore, people prefer the use of an automatic drain valve that is powered by electricity. This is the best solution if the air compressors have a large capacity.

You need to remove the valve that is on the device. After that, it is replaced with an electronic device. Thereafter, you have to set how often the compressor will merge. If you use the compressor every day, the timer is set to 1 time per day.

The automatic valve needs 12V power. Don’t forget to put a pan so that the water flows into it. There are a few precautions to take if you are emptying your air compressor:

  • first, disconnect the compressor from the power source;
  • protect yourself with goggles and gloves;
  • tilt the device so that the water flows better;
  • once draining an air compressor is complete, close the valve tightly. If necessary, use adhesive tape to seal;
  • test for leaks using soapy water.

Work carefully so that the compressor does not fall. Even a slight impact can ruin the integrity of the device structure, so avoiding breaks will be more difficult.

How to store an unused air compressor?

Once you are familiar with the principle of emptying the air compressor, you should learn how to store it when you are not using it.

It is important to first make sure that the compressor is empty. If moisture remains, it can cause corrosion.

Storage should be in a dry and cool place. This avoids damage to the internal and external elements.

Can the compressor start if the drain is open?

It is often necessary to start the device if the drain is open. However, if you do this, the compressor cannot build up pressure.

This can cause the compressor to burn out. You may start the device if the drain is partially cracked.

This is handy if you plan to paint a vehicle or run a sandblaster. Regardless of the scenario, the compressor will run, causing water to harm the project.

If you open the drain a little, you can drain the water during operation. This creates a dry air source.

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The volume of water created by an air compressor

As soon as the air inside the compressor tank begins to compress, this contributes to an increase in pressure.

If there is some moisture in the compressed air that gets inside, water vapor condenses under pressure. Because of this, water forms inside. The longer the device is running, the more moisture will accumulate.

Can the air compressor be tilted when draining?

The answer to this question depends on where exactly the drain valve is located. If the device is small and is designed for up to 6 gallons of water, tilting the device is not difficult.

This also has to be done if the compressor tank is on the side.

When tilted, moisture from both ends begins to exit through the tank drain valve at both ends.

Otherwise, when air is released and pressure is formed, most of the water will come out.

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When it comes to maintaining an air compressor, there can be different questions. Detailed answers to them will be presented below.

Do I need to drain my air compressor?

Yes, you need to drain the air compressor. The steps depend on which device you are using.

Often the manufacturer indicates the exact order of maintenance in the instruction manual. Almost everyone says that you have to drain the water from the compressor every day.

Where is the drain valve on an air compressor?

Condensate drain valves are compact devices. Almost all of them are located at the bottom of the device.

Depending on whether the air compressor’s tank drain valve is open or closed, water may drain or remain inside. So, everything must be checked.

What happens if you don’t drain water from the compressor?

If you don’t drain your air compressor, rust will build up inside the compressor tank. In this case, the drain will rust, due to which its performance will deteriorate.

Instead of air, the container accumulates water, so it will come out of the air hose.


As you can see, it is extremely important to drain the water from the air compressor tank. This depends on the duration of the device. It is significant to note that draining should be carried out at a certain interval, depending on how often you run the device for compressed air.

Read More About How To Drain An Air Compressor

James Cole

Considering that most people continue to pay the masters in the service for a consultation, I decided to create my blog.

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