How Often Should Air Dryer Purge

How Often Should Air Dryer Purge?


You’re driving your truck on a sunny morning and alas! All of a sudden you find that your air dryer is purging every 30 seconds! Does this situation sound familiar?

If so, throw away all your doubts. With this guide, you’ll have a definitive answer on how often should air dryer purge

Moreover, we’ll give you some insight into why an air dryer is needed, what it does and what would happen if it wasn’t there at all. That way, you’ll have a clear picture of the whole thing.

So without wasting time any further, let’s get the engine started!

Air Dryers- the Basic Knowhow

Before we know how often an air dryer should purge, let’s understand the mechanism of an air dryer. What does it actually do? Why is it important?

Let’s find out all the answers together.

You may have some basic idea about an air dryer. Here’s a clear picture.

Why is an air dryer needed?

Trucks that are equipped with air brakes have an air compressor. The job of a compressor is to keep the air tanks of the truck full.  Wonder why?

A little off-topic, but it’s necessary for the compressor to keep the tanks full. That way, there is enough air available to brake the car. 

Now coming to the air drying part. Whichever part of the world you may live in, the air most certainly has moisture and humidity.

This is constant even if you live in a super dry area. This air that carries moisture goes through a compression process by the air compressor. When air is compressed, it is automatically heated.

As this heated air passes through the discharge line to the air tank of the truck, it slowly cools down. Now I guess we all know what that leads to. 

If not, we’re here to jog your memory. 

When hot moisture carrying air cools down, it leads to condensation. In our context, this water drips down and pools to the bottom of the air tanks, pipes, and hoses of the truck.

Moreover, sometimes compressor oil or contaminants from the air filter of the compressor also end up collecting with the pooled water. 

What does an air dryer do?

If this water and debris are not removed, it can cause corrosion and damage to vehicles. So it’s crucial to remove the condensed moisture from the tank. Here’s where our air dryer saves the day!

So we told you why an air dryer is needed. But what does it exactly do?

An air dryer is made to remove or decrease the amount of humidity and debris that get collected to the air tank. 

What is air dryer purging?

The process of the air drying spitting out this debris is known as purging. The problem occurs when the air dryer keeps purging way too frequently.

Sometimes the situation could also be reversed. You may find your air dryer not purging at all. This is when troubleshooting or having an idea about the purging process really comes to help. 

The purging system works on its own. There is a pressure that is set beforehand in the air compression system. When the air compressor reaches the preset pressure, the air dryer purges.

Air Dryer Troubleshooting

Now let’s address what you’ve been waiting for. Did you find that your dryer is having problems purging? What should you do if you find yourself in this dilemma?

#Air leak

Firstly, it’s not okay for your air dryer to be purging every 30 seconds. If you find yourself in such a situation, this may be because of an air leak.

Like we previously mentioned, the air dryer only purges when the air compressor reaches a specific preset pressure. But if there’s a leak in the pipes or the air compressor, then a problem arises.

The leak doesn’t allow pressure to build up inside the air compressor. Thus, the air dryer also doesn’t purge. If you don’t fix this leak asap, it could lead to a buildup of water and debris in the air tank.

This will harm your vehicle and performance in the long run. 

You can check if there’s a leak from the pipes by pouring some soapy water on them. If there’s any minor leak which may be causing this, you’ll be able to tell.

The leak from the pipe will form bubbles in the soapy water. Even if there’s only a small air leak, you can nip the problem at the bud with this solution.

#Old air pipes

Also, if you find your air dryer purging way too frequently, you may want to change the small lines that carry air from the governor to the air dryer.

Even if these lines look like they’re working well, they may be damaged inside. So before you try rebuilding your air dryer from scratch, try doing this.

#Plugged Cartridge

If it’s not old pipes either, then this could be because of a plugged air cartridge. You see, the components in your air dryer need changing every once a while. If you don’t frequently service your truck, it could lead to such problems. 

In general, the dryer cartridge needs to be changed at least once a year. If you don’t remember the last time you’ve done this, then maybe it’s time to hit the garage. 

How Often Should Air Dryer Purge?

Now that we’ve looked at the problems you could possibly face, and their solution, let’s defeat the final boss. 

So how often should your air dryer exactly purge? Sadly, there’s no “one shoe fits all” solution to this. 

In short, if all the components of your compressor and air dryer are working smoothly, your air dyer will purge when the compressor reaches the pressure that was preset. 

Moreover, this will also depend on how often you’re braking the vehicle. This is cause every time the air governor unloads the air compressor, the air dryer purges. 


We hope you enjoyed reading our post and found something new. 

If you have any lingering queries on how often should air dryer purge, feel free to comment. 

We’d love to hear from you. Also, tell us about your experience with an air dryer. We’ll be waiting!

As an Amazon Associate I earn from qualifying purchases.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top