How to Keep Water Out of Air Compressor Lines

An air compressor is a popular tool that converts power into potential energy stored in pressurized air.

To keep water out of your air compressor lines, you can manually drain the air compressor tank or purchase an air dryer for around $1360 to automatically regulate the pressure dew point. Additionally, you can use a water separator filter to remove 50% of the water from the existing air or the storage tank cooling method for approximately $2000 per tank.

Keeping water out of air compressor lines is not only important because it can keep the machine running smoothly, but it can also keep your business or home dry and safe!

Keep reading to discover how water gets inside air compressor lines, how to remove moisture and what that might cost you, and how to keep water out of your air compressor altogether.

How does water get inside air compressor lines?

Water can enter the air compressor line through any number of leaks, holes, or openings. If there is a leak in one part of the system (for example, where it connects to an overhead tank), water will travel along that path until it reaches another opening and continues on its way to your machine.

Humidity from both indoor and outdoor air, which occurs during the compression process, and the overall condition of the air being used are just a couple of reasons for water to build up in your air compressor. The compressor’s filtration system isolates pure air from additional contaminants, such as moisture; however, sometimes, it does not work properly.

Water condenses whenever air is compressed. The water vapor in the incoming air will condense if the dew point is high enough after being compressed.

This is why water droplets form as a result of compression. Essentially, the more time you run your compressor, the more moisture it will collect.

What is the Pressure Dew Point (PDP)?

When looking for the root of the moisture buildup in your air compressor lines, it’s essential to understand pressure dew point and its contributing factors.

The dew point temperature of compressed air (usually around 72°F) at pressures higher than atmospheric pressure is measured using the pressure dew point. It describes the dew point temperature of a gas or air under pressure. This is important because the dew point is the temperature at which your compressed air becomes saturated. That air can hold no additional water vapor, so the steam begins to condense, thus resulting in water collection in the air compressor lines.

Compressed air dew point temperatures may decline depending on the surroundings. Compressed air produced by compressor systems without any ability to dry is often saturated at room temperature.

How is water harmful to your air compressor?

Excessive moisture is not only harmful to your air compressor because of the damage it can cause, but if left untreated for an extended period of time, water in the system could lead to more serious problems.

Water is harmful to your air compressor because too much moisture collecting inside an air tank or other components within the line can cause electrical problems with the motor, pump, and receiver.

Additionally, as the seasons change, this collected water can freeze during colder weather. This can cause the tank to crack and, of course, keep your compressor from working properly.

How do I remove water from air compressor lines?

If you suspect your air compressor has water buildup, there are a few steps you can take to drain its tank. This video details the process step-by-step.

Draining the air compressor tank:

Step 1: Turn off and unplug your machine.

Step 2: Place a bin or pan underneath the compressor’s drain plug to collect the released water.

Step 3: Twist the bolt to the left with your finger to begin releasing air (you may need a wrench to loosen the screw).

Step 4: Let all of the air drain out of the compressor first before turning the screw a few more times to the left and releasing the water (skipping this will cause the pressurized water to shoot out).

Step 5: Let the tank drain for as long as it takes for the water leakage to stop. Once it stops, re-tighten the bolt with a wrench and toss the water collected in the pan/bin!

How often should I drain my air compressor tank?

In order to prevent corrosion and prolong the lifespan of your air compressor, you should drain your tank frequently.

It is recommended to drain your air compressor tank after each use, either manually or automatically.

This habit will keep it functioning smoothly and ready for each usage!

What is the cost of replacing your air compressor?

If you’ve followed the above protocol and your air compressor still isn’t functioning properly, it’s time to consider a replacement. How much will this set you back?

While the average small, portable air compressor costs about $375, the industrial version is around $1400 (with parts and labor included).

Now you can see why proper maintenance is so vital.

How can I prevent water from penetrating air compressor lines in the future?

There are a few different ways to keep moisture out of your air compressor system so that you don’t have to drain it manually between each use.

To do so, you can use air dryers, a water separator filter, or the storage tank cooling method.

Air Dryers

There are three different types of air dryers to consider that cost, on average $1,360:

  • Refrigerated Air Dryer
  • Deliquescent Air Dryer
  • Desiccant Air Dryer

Here’s how they work.

Refrigerated Air Dryer

This air dryer system dehumidifies the air through a rapid cooling, condensation, and drainage procedure. It’s similar to the air conditioning system in your home.

A refrigerated air dryer decreases the air to a specific temperature, which is about 42.5°F (or 6°C). As a consequence of this, the pressure dew point is 36°F (2°C). The water evaporates from the air and is separated, after which it is heated and routed through the lines for its final use. The average cost of these machines is $2000.

There are two types of refrigerated air dryers: non-cycling and cycling.

Cycling dryers use additional equipment like frequency controllers, which would allow the dryer to turn on and shut down based on the compressed air demand coming into the unit.

This feature ultimately makes it much more energy-efficient. While the price of a cycling dryer is much higher than that of a non-cycling version, it does show the lowest overall lifespan cost. 

Non-cycling dryers work by shutting down and restarting to maintain the desired temperature. In a refrigerated air dryer, the compressed air temperature is lowered to 37° F (almost freezing), which allows for water to drop out from its vapor state, resulting in dry air beneficial for most applications. They are a reliable and cost-efficient option.

Deliquescent Air Dryer

Deliquescent air dryers are much cheaper and easier to use than their counterparts.

These air dryers require no electricity; however, the dew point is only about 22° F lower than the temperature of the air entering the machine. Deliquescent dryers consist of a pressure vessel with salt tablets inside that soak up moisture from the air. Just run the compressed air through the dryer and allow the salt to remove the water, similar to a Brita water filter restricting contaminants in drinking water. They cost about $600.

Desiccant Air Dryer

Finally, there are desiccant air dryers, which have the broadest range of applications and can keep moisture out while lowering the temperature less than other dryers.

This method is based on adsorption, which means that the dryer contains desiccant material (a silica gel, for example) that attracts water molecules from compressed air. A desiccant air dryer consists of two tanks- the active tank that filters moisture and releases dry, compressed gas and the regeneration tank that dries the desiccant. These cost about $1500.

Utilizing a desiccant air dryer is just another way to keep the water out of your air compressor.

Water Separator Filter

A water separator filter is designed to remove all the moisture from the air compressor. It filters out all sorts of contaminants from the compressed air, delivering cleaner and drier air to your equipment.

This filter works to eliminate most liquid and solid particles from the air supply. This water separator filtration system acts as a centrifuge to remove large amounts of moisture from the air supply. Typically, a water separator filter will remove 50% of the water from the existing air. They are incredibly affordable at about $50 per device.

This is another effective way to keep the water out of your air compressor and ensure it is firing on all cylinders.

Storage Tank Cooling

The storage tank cooling technique of drying compressed air works by utilizing a temporary receiver tank (or storage tank) to hold the air for a period of time and transform some of the moisture in the air into water droplets before allowing for the drier air to exit.

If the air is stored in the tank for enough time, the air temperature in the tank will match the room temperature, and no more moisture will be produced. It is essential that the water that is collected by the receiver tank is drained after each use to maintain the integrity of the steel walls. A storage tank costs about $2000.

Storage tank cooling is a rather costly and time-consuming method but effective nonetheless. Because you still have to drain the storage tank, it’s really no different than manual draining of an air compressor.

In Conclusion

The more you know about your air compressor and the various options for keeping it dry, the better off you will be.

If you have a small business with an air system prone to water damage due to high humidity or other conditions, investing in preventative measures can save both time and money down the road.

Take these considerations into account when evaluating which of these methods are suitable for how to keep water out of your air compressor lines.

      Residential & Commercial Air Compressors