How to Winterize a Sprinkler System – Blow Out Method

In Georgia, we don’t really worry about winterizing systems because we never really freeze.

What is the big deal with winterizing systems for you guys? Well, further north in the Midwest we have extended periods of cold temperatures, and it cause the ground to freeze as deep as 2 feet up to 3 feet even further north of here.

If you don’t do a good job of getting all the water out of the pipes in the ground, you can have significant damage when you go to turn your system on again in the Spring. Okay, so why not just use an automatic drain or just dig the pipes …

Bury them deeper? Installing the system deeper we would have to trench lines 3 and a half 4 feet deep to get it below the freeze line. That would add a tremendous expense to the irrigation system. Automatic draining systems are wonderful in a lot of aspects, but they waste a lot of water and they have the tendency to either fail open or fail closed which can lead to either a high water bill or frozen and broken pipes.

What are some things we need to consider before we blow out a system with air? Walk me through that entire process. For us the primary considerations we look at are, do you have any above ground piping. Do you have an RP backflow or PVB backflow? Those are always above ground and damaging those due to freezing temperatures will cost significantly more than what it cost to winterize your system appropriately. Some people will have their systems completely underground with a double check backflow.

For those you can usually wait till later in the year to winterize them. Temperatures below 30 degrees are a red flag that you need to get your system shut off and blown out immediately. Anything below that can cause damage, cracked pipes, broken backflow preventers, any and all of those. The first thing we\’re going to do is we’re going to shut the water off in the basement.

Depending on your sprinkler system it might be in the front yard or the side yard in a pit in the ground. Once we shut the water off then we can hook up our air compressor and blow all the water out of the sprinkler system.

Now, how much pressure is it going to take to blow that system out? Typically we run our compressors at 80 PSI, anything above 80 PSI and you have the potential to damage your irrigation system. Now I have … I know I have a compressor in my garage right now that will generate 80 PSI.

Why can’t I just use that? It doesn’t look anything like this guy right here. The typically homeowner air compressor absolutely can generate 80 PSI and more, but it cannot generate the same volume that one of these compressors can. The volume allows us to do it, 1 more quickly and 2 more thoroughly than the homeowner’s compressor can.

If I did it with my compressor I’ll be out there forever trying to blow out the system? It takes significantly longer, and it has the potential to not get all the water out, yes. Okay, I’m excited to do this. Let’s go get started. Excellent. All right, here we are at the backflow device and I see the connection point for the hose. Are we ready to just hook it up and go? Not, quite yet. First thing we need to do is go downstairs and turn the water off.

Depending on the house or the residence you may have your shut off in the basement or in a crawl space. The other option is in the yard by the water meter usually in a value box. Okay, the waters turned off. Now can we hook up the hose? Just about. The first thing we’re going to do is we’re going to turn this off to isolate the backflow and not allow air to go backwards through it. Okay. We’re getting really close now. Thank goodness.

The next step is we’re going to remove the blow out cap. All right be careful when you remove the cap sometimes there can be a lot of pressure behind these so do it slowly. Then we need to connect our adapter so that we can connect to the hose. All right then your favorite part let\’s get it connected. There we go. Now, keep in mind one thing that is really important is that we connect after the backflow preventer. All too often people will connect through the different test cocks here on the backflow or to another point on the other side of the backflow.

Running air through a backflow preventer can cause significant damage to the backflow. Okay, also we have the hose connected. We can’t just turn the compressor on and build up pressure on a closed system? Nope absolutely. If the air doesn’t have anywhere to go it can burst pipe. The first thing we’re going to do before we fire up the compressor and going to turn on the controller to zone 1, and then we’re going to manually go through each individual zone until all the waters out of the system.

Well, now we’re at the compressor. Okay. First thing we need to do is make sure that this ball valve is cracked slightly open and then we can go ahead and fire it up and see what happens. All right, let’s do it. Okay, behind us is the last zone that we must blow out. I’ve noticed that you’re not waiting until the heads run clear with air before you advance to the next zone. What are you doing on that? When they first come on a steady stream of water will come out. Then as the air continues to work through the system it will turn from a mist to a fog. The goal is to have every head spraying a fog. At that point the zones done.

Okay, when this final zone is done how do we finish this up? We head back to the compressor turn it off, then we’ll go back to the backflow and finish up there. Okay. Okay, looks like we’re back where we started. Now I understand that we’ve got everything cleared out from the discharge side of this backflow device out to the heads.

What are we going to do about the water that’s in the line from the point of connection through the backflow device to that value?

Great question. First thing we’re going to do is disconnect the line going back to the compressor and we’re going to remove the adapter. Then we’re going to put the cap back in, but we’re just barely going to put it in in case any water gets into the line here over the course of the winter it has a spot to get out. Then for the backflow preventer and the supply line first thing we’re going to do is take each of these ball valves and turn them a quarter turn. That allows any water that might be trapped on the outside of the ball value an opportunity to get out and prevent any cracking of the ball values.

We do the same thing with each of the 4 test cocks because they’re little ball values. It will also give the water an opportunity to drain out if any does get in there. It’s really easy for a homeowner to accidentally turn the water on and introduce water back into it.

Finally we need to head downstairs to the point of connection and open up the drain so that we can get the little bit of water that’s left in the supply line out. You can see that winterizing your system is crucial to maintaining your irrigation system in colder climates. Not doing so can lead to broken pipes, damage to your backflow device, and costly repairs.

If you feel like you’d rather have a handyman pro complete this or other projects for you, Pretty Handy Guys Handyman Services has local handyman pro ready to partner with you in your home improvement projects.

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