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How to Blow Out Sprinkler System with Air Compressor

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Having a sprinkler system on your property makes maintenance of your garden/yard a breeze.

But, you have to drain the system of all traces of water before the winter approaches to keep it functional for the next spring.

Else, you might have to reinstall the entire system again when the time comes.

This will leave you thousands of dollars poorer.

So, its better to go for an easy and cheaper alternative, i.e. learn how to blow out your sprinkler system with an air compressor.

This article will help you how to do this project without hiring professional help.

Why Is It Important to Winterize Your Sprinkler System?

You need to know why must you go through all the trouble to blow out your sprinkler system before learning the actual process.

As we all know, standing water is damaging, may it be inside the pipes or outside – on a surface.

The pipes of your irrigation system are designed to supply water to the land, not to house water remnants for an extended period.

The traces of water inside the pipings for a prolonged length of time can cause corrosion or mold buildup in the inner walls of the pipes.

Another worst thing that could happen is the embrittling of the pipes because of the ice formation when the temperature hits subzero level.

The traces of lingering water inside the pipes turn into ice when the cold spell begins, making them brittle and vulnerable to cracking.

In both circumstances, you will face costly repairs. Hence, you can avoid expensive and exhausting repairs by blowing out your sprinkler system before each fall.

How to Blow Out Your Sprinkler System with an Air Compressor

Now, we head to the actual task of teaching you how to blow out your sprinkler system using an air compressor.

Equipment Required for the Job

Make sure you have the following equipment at hand before initiating this DIY project to avoid frustration and wasting time.

  • Air compressor – a 4 – 6 gallon air compressor will do.
  • Air hose
  • Quick-connect adapter for the sprinkler bib
  • Protective goggles

Step by Step Guide

The following step by step process will help you successfully shut off the sprinkler system for the entire winter season.

  • Shut Off the Water Source

The first thing you need to do is to turnoff the water supply to stop the regular onslaught of water in the pipes.

The system will clear out itself to a great extent once the water supply is blocked.

However, remember that there will still remain traces of water inside the pipes.

They won’t drain naturally. Air compressor targets these lingering droplets.

  • Release the Pressure

In this step you have to drain out air from the system to release pressure on the pipes.

You can do that by opening the hose bib attached on the mainline of the irrigation system.

Don’t forget to cap valves on the backflow preventer to stop air from entering the pipes.

Make sure you keep the valves open of the section of the sprinkler system you’re working on to avoid bursting of the pipes.

  • Set Up the Air Compressor

Once you’ve drained out excess water and relieved pressure in the pipes, it is time to set up the air compressor.

Set and charge the unit according to the guidelines given in the owner’s manual.

It is important to only introduce the amount of that your sprinkler system can handle.

The power required for the task depends on the types of pipes the irrigation system has.

Rigid PVC pipes require 80psi, whereas 50psi is suffice for black polyethylene pipes.

You cannot blow out all the pipes of the sprinkler system at once.

You will have to go zone by zone because even the strongest and powerful household air compressor will be unable to blow out the entire sprinkler setup at once.

  • Connect the Air Compressor

Once all the lines are completely emptied, unplug the blow-out port to reveal an airhose adapter.

In the next step you need to take a long hose to connect its one end to the air compressor and other to the bib located on your sprinkler system’s mainline.

Make sure the hose isn’t cracked or leaking.

Remember, sometimes you might experience fitting issues between the bib and the airhose.

That’s when an adapter will come in handy. It will snugly fit the bib with the hose to prevent airleaks.

Keep a copy of your sprinkler layout within reach to know how much CFM will be required to blow out a section.

If you’ve correct information of the gallons released from each sprinkler head per minute,

You can calculate accurate CFM output you will need.

Divide the total water GPM of the zone you’re working on by 7.5 to get the CFM value needed for that section.

  • Turn On Your Air Compressor

Now that the air compressor is connected to the blow out line of the aimed zone,

Turn it on. Activate the system’s timer on the compressor by following farthest-to-nearest sequence.

If your sprinkler system is spread across a large property having high and low planes, go for the zones on higher planes first.

This practice will help you check the overall power of your compressor’s current settings and hose attachment to make timely adjustments.

Open your air compressor’s valve to let the air flow into the sprinkler system.

As the air works its way through the pipes, you will see debris and foliage sprouting out of the sprinkling outlets.

Make sure you have protective goggles on to protect your eyes from flying particles.

It will take around two minutes to blow out one zone. Drain as much water as you can from the sprinkler lines in the given time.

Refrain from running sprinkler heads dry for longer to avoid overheat and melting as they usually have plastic components.

Move to the next zone and let the previous one cool down. If necessary, you can dry the remaining water in second attempt.

When water stops sprouting out of the sprinkler, head towards the next zone. Repeat the same process for every segment.

  • Disconnect the Air Compressor

When the sprinkler of the last section stops emitting water, know that you’ve successfully saved your sprinkler system from winter-related problems.

It’s time to wrap up your equipment.

Turn off your air compressor and disconnect the hose.

Leave the blow-out port open for a while to let the excess air pressure bleed out of the lines.

Take air compressor and hose back to their storage place.

Time to call it a day.

A Golden Nugget: Prefer gasoline-powered air compressor – having at least 20+ CFM @ 50psi – over its electrical counterpart.

The latter could be dangerous as you will be working with water lines.

Conclusion

It is better to take timely action and drain your sprinkler system of the last droplet of water before winter spell begins.

Otherwise, you might have to go through lengthy and costly repairs.

The article above shows that you need a few tools at hand to blow out the sprinkler system with an air compressor on your own.

Follow each and every step to ensure your sprinkler system stays healthy and functional for the next spring.

Ivan Sanchez
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About Ivan Sanchez

Ivan Sanchez is a passionate blogger, traveler and certified Mechanic and moreover owns a Mechanic Shop in Norway too. He loves Painting Cars, Fixing them and a lot more. His father had a shop too where he used to sell Air Compressors, that's where Ivan learned about it and now reviewing some top-notch air compressors through this blog for you.