How To Blow Out A Sprinkler System | RMBA

How to blow out your sprinkler system by Rocky Mountain Bio-Ag

Homeowners are well aware of the importance of protecting the inside of their home, and all of their outdoor property. For people who live in the northern area of the country or where snow and other damaging winter weather are common, take precautions to make sure that your outdoor equipment is kept safe. This is especially true, and vital, for lawn sprinkler systems and drip irrigation for landscapes.

Why is it Important to Blow Out My Sprinkler System? 

Both sprinkler and drip irrigation systems need to be protected against freezing. If you leave the water in them that’s been there since summer use, the lines and pipes can burst in freezing temps. To ensure that the lines are drained properly you will need to manually remove the water or blow out your sprinkler system using an air compressor. If you want the system to be fully operational come spring as temperatures begin to rise it is a task that must be completed in the fall before deep freezes damage the system. 

Will My Lawn Management Company Blow Out My Sprinkler System?

If you have a service that handles your lawn management, then you may not need to be concerned about blowing out the sprinkler system. As this is a service most lawn management companies perform for their customers as part of their contract. When having professionals or lawn management companies blow out your system you can expect to pay a minimum of $50 for simple systems up to hundreds of dollars for more complex time-consuming systems.

Depending on how many zones your system contains and the size of pipe that was used to build your sprinkling system you may not have a choice but to hire professionals with large, commercial, tow-behind air compressors which produce enough continuous air volume to extract the water from your system.

Sprinkler Blow Out Safety Gear and Tools

Safety equipment that should be worn when blowing out sprinkler systems include ear protection, eye protection, gloves, pants, long sleeve shirts and closed toe shoes or boots.

The following tools may be required for your sprinkler blow outs: 

  • Water shutoff key if you're systems water supply is buried in the ground
  • Straight blade screwdriver
  • Phillips screwdriver
  • Pipe wrench
  • Strap wrench
  • Crescent wrench
  • Channellock pliers
  • Needle nose pliers
  • Proper fittings to connect the air compressor to the system

How Do You Blow Out a Lawn Sprinkler System for Winter?

When you have the responsibility of doing your own lawn care, then you need to be sure that blowing out the sprinkler system is something that you know how to do. Here are a few steps to help make this task a successful one.

  1. Locate and turn off the water
  2. Get your air compressor
  3. Blow out the system
  4. Leave water off until spring

1. Find the Shut-Off Valve and Turn off the Water

Step 1 Sprinkler Blowout: Turn off Water

The first thing to do is to locate and turn off the water to the sprinkler system with the master shut-off valve. This may be found in an outdoor shed, a utility room, or in the basement of some homes. The location of the valve will depend on when the home was built and who installed the sprinkler system.

To check that the water has been shut off to the sprinkler system, locate the backflow preventer. Once the backflow preventer is located there are test cocks which can be opened with a straight blade screwdriver. Slowly open one of the test cocks making sure that no water sprays out.

If no water sprays out, the water to the sprinkling system has been successfully turned off. You may choose to leave one of the test cocks slightly open to lessen the pressure that flows through the pipes when blowing out the sprinkler system.

2. Obtain an Air Compressor

Blow Out Sprinkler Step Two: Get Air Compressor

You will need an air compressor to complete the blow out of the system. If you do not have one already, you can rent one from a local equipment rental company or buy one, which you will have for years to come. If renting a compressor, make sure to reserve the unit well in advance as rented compressors are hard to come by when it is time for sprinkler blow outs. 

If you purchase an air compressor, make sure that the unit is large enough, including the size of the air holding tank to handle the system you are blowing out. You will want to set the pressure regulator at approximately 60 psi (pounds per square inch), which is sufficient for most common home systems. Do not go any higher than 60 psi as it can cause damage to your system and may cause plastic pipes to explode.

3. Blow Out Your Sprinkler System


How to blow out my sprinkler system Step 3: Blow Out the System

Check to make sure the compressor is turned off and there's no air which will be released when attached to the sprinkler system, then attach it to the blow out point. The fittings may not match, so be creative in order to have a secure seal between the compressor and the system. Using fittings that do not constrict the air flow will help with the volume of air moving into the system for the blow out. Lastly, close any hose bibs and the test cocks on the backflow preventer which you opened to see if the water to the system was turned off in step 1.

Find the sprinkler controller box if you have an automatic sprinkler system and manually run the station that is furthest from where the air compressor is connected for the blow out. If you do not have an automatic system, make sure that you have manually opened the valve for the zone furthest from where the air compressor is connected for the blow out. Once the hose bibs and test cocks are closed and a zone is opened the air compressor should be plugged in or running if it is a commercial tow behind unit make sure that it is fully charged or ready to dispense air.

Turn on the air valve or pressure regulator to allow air flow into the sprinkling system. Continue to work through the zones starting with the farthest and work your way to the one that is closest to the blow out point where the air compressor is connected to the system. Each zone needs to be on for approximately two minutes.  Keep watching the water as it sprinkles from the system. The water will turn from a full stream to a mist and then to air with very little to no water. The air with very little to no water lets you know that it is time to go to the next zone.

Drip Irrigation System Blow Out Tips

If you have drip irrigation sprinklers, you may need to blow out the zone for a longer period of time because the drip emitters do not dispense as much water as lawn sprinklers. If you can find the end of the supply line for drip systems, there is usually an end of line cap which can be removed to allow the water to be extracted quicker. When you get to the zone that is closest to the blow out point where the air compressor is connected to the system the sprinkler system has been completely blown out.

4. Keep the Water Off Until Spring

How to blow out my sprinkler system Step 4: Leave Water Off

Any hose bibs or ball valves including the two on the backflow preventer should not be closed completely but left slightly opened (approximately 50%)  to make sure the valves do not freeze. There are also test cocks on backflow preventers which should be slightly opened (approximatley 50%) using a straight blade screwdriver. The only valve that needs to be left completely closed is the water supply valve, which supplies water to the sprinkling system.

Once the system is blown out DO NOT OPEN the water supply valve or you will have to start the blow out process again from the beginning. It is important that you have extracted all water from your sprinkling system, or you will risk freezing pipes and valves. Freezing pipes and valves is a very costly and time-consuming problem to deal with in the spring when trying to restart your system. Also, make sure that you have disconnected and drained all water hoses that are connected to hose bibs.

This can be an easy job if you are familiar with taking care of lawns and sprinkler systems. If this is something new for you, be careful with handling the equipment. The sprinkler system is a very important part of the home outdoor necessities. You want it to work properly when the time comes next spring to turn it on. 

Blowing out the system ensures that there will be no problem keeping the lawn beautiful and hydrated during the heat of the summer. Always check with the experts that you rent or purchase the air compressor from and get a full understanding about how to use the equipment and the amount of pressure that should be used to complete the water system blow out task. ALWAYS wear safety equipment when blowing out sprinkler systems.

How to blow out your sprinkler system infographic

Author Bio : Sarah works for YourGreenpal and she loves writing on lawns and garden related niche.

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