# DIY irrigation winterizing - use shop compressor?



## GroundLoop (Aug 15, 2021)

We recently purchased a home that has a 12 zone professionally installed irrigation system in the Chicago area. I started the irrigation system in the Spring and now it is time to winterize it. It has a 3/4 hose connection for the blow out connection. I have 2 air compressors: 1 is a portable 110v with a 6 gal tank and the other is a stationary 220v 60 gal in the workshop. Do not think the 6 gal would have enough volume. The 60 gal is about 150 ft away from the blow out connection. Was thinking of getting an extra 100ft 3/8 hose which would be enough to connect to the blow out connection. Does this sound like it would work? Do I need to lower the pressure down any? I image the 150 ft of hose is going to lower the pressure.


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## BurtMacklinFBI (Jul 17, 2021)

I cant speak for pressure loss over that distance. I think hose diameter would play a factor not the length. That said you are overthinking it haha. Just plug into your 60gal and set the pressure out to 50 to 60psi. I know a guy who installs irrigation and thats what he blows out at (50 to 60) I just did mine today actually. I have a belt driven.... I think 30gal but not positive on that tank size. I know it won't keep up with the air going out. Technically the best compressor is one that can just run and keep up pressure but that gets pricy. The guy I know has a small truck mounted comp. By small I mean small tank but motor wise it keeps up, so tank size isn't as important for him. Your big comp will be fine. Heres how I do mine.

I fill the tank till it shuts off, open a zone and let the water get pushed out till all heads on that zone are spitting and sputtering air and close that zone. I'll come back to it again.

I do this for every zone with a fresh tank. The comp may kick on (it kicked on every time so one tank wasn't enough for me but I also don't want my comp running continuously and getting too hot) So just empty out all the water per zone till they start sputtering.

Once they are all drained I go back to the first zone and throw another tank (maybe a full tank and a few minutes worth of the comp running) By letting the empty zone sit for a bit, I find this let's the remaining water droplets to pool up and run down to the lowest point. So this second blowing session takes care of the rest of the water left over from the first session.

Going back and doing a second blast is probably overkill but since its something to do on a weekend once a year..... why not over do it haha.

Oh and make sure to shut off your water first :lol: and then isolate your backflow to prevent damage to the diaphragm. One of my friends blows out his system thru the backflow..... pretty sure that isn't good haha. His blowout hookup is between the water source shutoff valve and the backflow so.... it is what it is I guess.


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## Rucraz2 (Apr 8, 2018)

My blow out is before the backflow preventer as well. Never been an issue. I have a 40gal compressor I do the same thing with. I roll the tank right up to my valve and use a pressure regulator right there. Run 3/4 tank on each on my 16 zones. Then a quick 2nd time and done. I have tubing to run in my garage eventually. When I do, I will have extra to just plumb into my basement to blow out. Then I won't have to move my tank, but I will have a lot more hose to go through.


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## BurtMacklinFBI (Jul 17, 2021)

Rucraz2 said:


> I have tubing to run in my garage eventually. When I do, I will have extra to just plumb into my basement to blow out. Then I won't have to move my tank, but I will have a lot more hose to go through.


When I plumbed the water line thru the basement I came so close to plumbing an airline so I'd have a quick release air fitting right outside next to the backflow. Would have been a clean setup.

Also if you have say 50psi of water pressure and you blow 50psi of air thru the line.... whats the difference haha. When I plumbed my B.F. everything online said to put the blowout connection after the B.F. I've also never seen one before the B.F. till I seen my buddies.


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## Rucraz2 (Apr 8, 2018)

I've seen guys hook directly up to the BF to blow out. I know the sprinkler guy around here connects before it. It's not the psi that is the biggest issue it's the cfm. I know some guys that have blown out some shorter lines with pancake compressors, but they didn't have very long runs. I sometimes worry about mine with the longer runs, but the 4yrs I've done it this way, I have yet to run into any problems.


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## g-man (Jun 15, 2017)

There should be an old thread about this from previous years. The main areas of concern is not really pressure, but cfm. You want enough airflow to lift the water in the lowest point of the laterals up thru the sprinkler heads. Pressure wont help when the full diameter of the pipe is not covered by water. The second area of concern is heat. The compressed air can get hot.


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## Lust4Lawn (Aug 4, 2020)

One year I did this with my fairly strong 6.2 CFM @ 40 psi or 5.3 @ 90 psi compressor. Then I had my sprinkler company come out and blow it out with their tow behind compressor. At least for my system, there was so much water still in the lines that I decided that I would never try blowing out myself again. Clearly, I had many areas with partially filled pipes with my compressor just blowing air over the top of the water.

For me there is too much downside potential and I just pay for the service. I'm not saying everyone's system is like this, but if you have doubts this is a potential way to sort it out.


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