What Size Air Compressor To Blow Out Sprinklers

When talking about what size air compressor to blow out sprinklers, volume is going to be the key. It’s less the size of the compressor than the volume of air available for the initial “push” that counts. Once you get the water in the lines moving you have to keep it moving until the most of it is blown out, similar to blowing out RV water lines or buried garden hoses. For blowing out our sprinkler system, we need to know the exact size of an air compressor for sprinkler blowout because different sizes of air compressor require different CFM, PSI, and tank sizes.

What Size Air Compressor To Blow Out Sprinklers

What Size Air Compressor To Blow Out Sprinklers

It is very important to choose the right air compressor for blowing out your sprinkler system. In this article, we will cover all the aspects and will help you what size air compressor to blow out sprinklers. So let’s get started!

When it comes to choosing an air compressor for sprinkler blowout, mainly we have to consider CFM, the volume of air, and psi, the pressure of that air.

Doing an annual blow out each fall, you can save costly system repairs and maintenance cost down the line.

Factors To Consider When Selecting An Air Compressor To Blow Out Sprinklers

Here are some points to keep in mind before buying an air compressor for sprinkler blowout:

1- Constant Air Flow

2- Horsepower (HP)

3- CFM

4- PSI

5- Portability

6- Noise Level

7- Durability

Constant Air Flow:

Blowing out a sprinkler system requires a minimum of 2 minutes continuous air flow at 20CFM. Before buying an air compressor for sprinkler blowout, check out whether it can supply 20 CFM air for at least 2 minutes.

Horsepower (HP):

Horsepower (HP) is mainly the power that comes out of an air compressor motor. We all know that an engine is the heart of an air compressor. So, for blowing out sprinkler system, you have to choose at least a 4 HP air compressor.


The rate at which a compressor can draw in air and compress it is expressed as CFM, or cubic feet per minute.

For blowing out sprinkler system, a minimum of 6 CFM is required to carry out operation smoothly. It can allow you to go for a large to small pipeline diameter for the zone by zone blowout.

The ideal air compressor for sprinkler blowout typically produces between 20 to 50 CFM at 50 psi.

CFM Calculation Formula

You can calculate a rough estimate of the required CFM for your sprinkler blowout using this simple formula:

GPM per Zone / 7.5 = CFM Requirement

In other words, take the GPM of each sprinkler zone and divide it by 7.5 to get a quick estimate of the required CFM. For example, a 150 GPM system divided by 7.5 would require 20 CFM of compressed air. If you plan to blow out multiple zones at a time, your CFM requirements will increase accordingly.

Lower CFM ranges are ideal for smaller pipes under 1”, while larger CFM ranges may be required for pipes larger than 1”.


The degree to which the air is compressed and held in the air tank is expressed in terms of PSI, or pounds per square inch.

Regardless of the required CFM, the psi should always remain balanced for blowing out your sprinkler system. If an air compressor doesn’t produce enough air, water drops will remain in the pipes. On the other hand, if the PSI is too high, the compressed air can crack your sprinkler pipes and break sprinkler heads, causing permanent damage to the irrigation system.

Polyethylene pipe is more likely to break above 50 psi, while rigid PVC pipe can handle slightly higher pressures of up to 80 psi.


For blowing out sprinkler system with an air compressor, you must have to pick a portable one. Because you may have to move your air compressor from one pipe to the other, so it is very important that you are using a portable air compressor to make your task convenient.

Noise Level:

We always recommend going for a quieter air compressor, specially for blowing out your sprinkler system. You can get some air compressors for lesser price from the market, but their louder noise will create much trouble. And, the high noise level is one of those troubles that can make your task hectic.


Last but not the least; also make sure you buy the air compressor from a renowned brand, which is known for its durability, because you have to blow out your sprinkler system every year. If your air compressor is not durable, it will not be able to carry out the task next year. So always consider this point when picking up an air compressor for sprinkler blowout.

Which Air Compressor To Choose:

When you are determining about the size of air compressor to blow out sprinklers, you must keep these below mentioned points in mind:

Powerful or Portable?

When you are determining about the size of air compressor to blow out sprinklers, you must keep the right balance between air compressor’s power and portability.

Air compressors are available in a wide range of capacities and configurations, from high-capacity stationary ones to light-duty portable units. You have to calculate the required amount of pressure required to blow out your sprinkler system by calculating your area and the required CFM through formula we discussed above.

Make sure the air compressor is powerful enough to provide the required CFM. But at the same time, your air compressor needs to be portable so you can move it where required.

Electrical or Gas-Powered?

The power source of an air compressor is another important aspect to keep in mind while blowing out sprinklers. Some air compressors are designed to run on electricity, while others on gasoline.

Gas-powered air compressors are heavier, noisier and more expensive than the electrical air compressors. Gas-powered air compressors require more maintenance and are unsuitable for indoor use. So, if you are willing to keep it only for outdoor use, like blowing out your sprinkler system, then you can go with a gas powered air compressor.

But generally we always recommend going with an electrically powered air compressor, until or unless you expect to use your compressor primarily in places where electricity is unavailable.

Electrically powered air compressors are intended for household applications plug into a standard 115-volt household circuit although some of the larger stationary compressors must be hard-wired into a 230-volt circuit.

Having said that, always keep in mind, when using an electrically powered air compressor for blowing out sprinkler system; it’s never advisable to use an extension. Instead, extend your reach by using a longer rubber air hose between the compressor and your sprinkler blow-out port.

Low Maintenance or Greater Longevity?

The maintenance cost of an air compressor is also an important aspect to keep in mind while blowing out sprinklers. Some air compressors are designed to be oil lubricated, while others are oil-free. Oil-lubricated air compressors need to be properly maintained.

It requires oil to minimize wear and to keep their parts running smoothly. Oil-lubricated air compressors tend to be heavier than the oil-free compressors and require more maintenance, but they also generally last longer. Oil-free air compressors are, as the name indicates, designed to run without the addition of oil. That makes them a popular and automatic choice for the occasional user.

Why it is important to Blow out Sprinkler System?

The main purpose of blowing out sprinkler system is to clear out all the little amount of remaining water from the pipes.

If this blow out process done properly, all the pipes in sprinkler system will be cleared and dried out, preventing the pipes from rot and corrode during winter months.

Many people just cover the sprinkler nozzle, valve heads with a plastic cover, thinking it will prevent their sprinkler system from freezing.

But that’s not the case. If you don’t properly blow out your sprinkler system, this water stars freezing inside the pipes, valve heads and in the sprinkler nozzle.

This freezing of water can cause a widespread damage of pipes from inside, can damage your valves, and can shatter your sprinkler nozzle.

So when you restart your sprinkler system after the winter, you will not get the same performance you experienced earlier.

And this is all because your sprinkler system is damaged from inside due to that freezing water.

Therefore, before you turn off your sprinkler system in colder months, it is very important to understand what size air compressor to blow out sprinklers to prevent it from any damage during winter days.

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