Should I Empty Air Compressor When Not in Use?

Should I Empty Air Compressor When Not in Use?

Are you wondering if you should drain your air compressor tank when it’s in storage? In this article, we’ll talk about why many people always drain their air compressors when they are not in use.

If you’ll be leaving your air compressor in storage, then it’s wise to empty the tank. Often, there will be a little bit of moisture in the air, and over time, this can begin to cause corrosion on the interior of the tank. Also, the continued pressure without relief could begin to cause problems. 

This guide will talk about when and why you should empty your air compressor. We’ll also discuss some of the dangers related to leaving your compressor tank full all the time.

Why Do You Need to Empty an Air Compressor?

The main reason to drain an air compressor during extended storage is to reduce the negative effects of moisture. In the next several sections, we’ll talk about four potential downsides to leaving your air compressor fully pressurized for extended periods.

Note: most modern air compressors are built to safely handle long-term pressure. The problems we are discussing today will be more likely over the long term. Know that air compressors can explode if allowed to corrode.

Here are several reasons to empty an air compressor regularly:

  • Rust in the tank
  • Rust in the lines and the tools
  • Moisture in the air (for painting)
  • Danger when unhooking hoses (depends on the compressor)

Below, we’ll look at each of these points in more depth.

Leaving Air Compressors Full Can Cause Rust in the Tank

The central principle to keep in mind is that there is water in the air, and when you fill your air compressor, this water can begin to accumulate within the compressor tank. The longer (and the more often) you leave the air compressor full, the more water your unit will be exposed to.

Now, air compressors are designed with an interior lining that will resist the corrosion of water. However, note the key word. Resists. One of the fundamental laws of life is this: water always wins. Even if it takes a long time.

Keeping this in mind, you could begin to see some reduction in the integrity of your air compressor tank if it is rarely emptied and repeatedly exposed to water. However, it’s not just your air compressor tank that will begin to show signs of wear when repeatedly exposed to condensation – let’s talk about several other risks.

Leaving an Air Compressor can Cause Rust in the Hose and Tools

Not only will water accumulation in your tank begin to cause rust in the tank itself, but it can also cause problems within the hose, or the tools that are attached to the tank. While the tank is a fairly simple structure (and will require a fair amount of time before rust begins to impact performance), hoses and attachments have much smaller parts.

Since attachments (like nail guns, paint sprayers, and more) are more calibrated, they could begin to show negative effects from rust sooner. So, by emptying your tank regularly, you’re not just saving your tank, you’re also protecting the tools and attachments.

Now let’s talk about another potential problem.

Built-Up Moisture in the Tank will Cause Moisture to Inhibit Projects

Perhaps you live in a very humid climate. If enough moisture builds up, you could see this impacting the actual projects. How so? Let’s use a paint sprayer as an example.

With a paint sprayer, you’re trying to rapidly and efficiently paint a wall or piece of furniture. However, if you have a small bit of water within the lines of the air compressor, you could achieve mixed results. If you’re using water-based paint, then the paint may be slightly diluted. However, if you choose to use oil-based paint, you could end up seeing some drips.

Overall, this isn’t a huge deal. However, if you’re a professional or you have a project that needs to be perfect, it’s something to consider. Your best bet is to regularly drain the air compressor tank and follow manufacturer guidelines for maintenance.

There can Be Danger when Unlatching Attachments from Full Air Compressors

Finally, in some air compressors, there might be a danger of uncoupling the hose or attachments while the unit is fully pressurized. This can be a particular problem if there was a long hose, and the hose is still full of pressure.

Some units have an automatic pressure release that will reduce these dangers; however, it’s important to check your model to ensure that you don’t have any issues. Regardless, for the sake of safety (and the overall integrity of the air compressor), it’s smart to get into the habit of releasing the pressure in the unit.

Now let’s talk about how often you should empty your air compressor.

How to Take Care of Your Air Compressor 

Let’s talk about a few things you can do to protect your air compressor.

How to protect an air compressor:

  • In general, empty the tank if it will be stored for several days
  • Follow the manufacturer’s guidelines closely

Now let’s go over these points in more depth.

Empty the Compressor Tank if It Will be Stored

A good rule is to empty your air compressor tank if the unit will be stored for more than a day or two. If you have an ongoing jobsite, many tanks will be made to stay full.

Many air compressors will be able to withstand full pressures for longer than a day or two. The purpose of releasing the pressure is to slow the effects of long-term corrosion.

One thing to keep in mind is the type of climate you’re in. If you live in a highly humid climate, then there’s a chance your unit will take in more moisture. In this case, you’d want to take steps to clear out your tank more often.

Now let’s talk about something a little boring (but very important, and often overlooked).

Follow the Manufacturer’s Guidelines Carefully

Air compressors are a little like snowflakes. Each model will operate a little differently and might require different maintenance. In this section, we’ll outline several reasons it’s so important to review your specific air compressor make and model.

To think about it another way, imagine two types of cars: a Toyota and a Ford. Yes, they are both vehicles, but each one will require vastly different maintenance. The same is true with air compressors, especially when comparing electric to gas models.

Here are three reasons to research your manufacturer’s guidelines for your air compressor:

  • They will have the most specific information
  • They will have specific warranty requirements

Let’s look at these in more depth.

Manufacturers have Specific Information about Air Compressors

As we mentioned, it’s important to find information related to your specific model of air compressor. While the internet is helpful, nothing replaces hearing instructions from the people who actually built the unit.

If you don’t have the manufacturer’s instructions (maybe you have an older model), try looking up the brand of the air compressor and calling or emailing the company – they will probably be able to provide you with an instruction manual.

However, this isn’t the only reason to read the instructions.

Specific Warranty Requirements for Your Air Compressor

Reading the manufacturer’s instructions will also ensure that you don’t void the warranty. Sometimes there are several small things that the manufacturers require for a specific air compressor.

This can be a little tricky because you might be used to leaving your old air compressor full all the time. However, if the new compressor has instructions that state you need to empty the air compressor every few days, then you’ll need to abide by this new rule; otherwise, your warranty won’t cover anything if something goes wrong (even if it wasn’t related to the tank).

Finally, contacting the manufacturer of your air compressor gives you someone to reach out to when something goes wrong (or you have a simple question). Many people don’t realize that they can reach out to these companies and get a response.

With all that said, let’s go over a few final thoughts.

Conclusion: Should You Store an Air Compressor with a Full Tank?

It’s important to follow your manufacturer’s guidelines when deciding when to empty and air compressor tank for storage. This will give you the best information regarding how and when you should empty the air compressor tank.

The truth is, air compressors vary quite a bit in how they are made, so you need to try to find specific information pertaining to your air compressor whenever possible.

In general, if you know your air compressor will be dormant for a couple of days, you should drain the tank and ensure that everything is properly cleared – this includes all the hoses or tools that were attached to the air compressor.

While air compressors are made to handle high pressures, leaving them full all the time will increase the chance of corrosion over time. Many air compressors will automatically drain the tank after a certain period of time. Familiarize yourself with your air compressor, and always play it safe.

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