# Issues blowing out lines



## SpiveyJr (Jun 7, 2018)

I had my lines blown out the other day and on some of the zones the heads would pop up squirt some water and then go back down before there was enough time to completely drain them. Has anyone heard of such a thing happening?


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## Mr McTurf (Jun 21, 2018)

My first thought would be is the pressure from the air compressor high enough? 40 PSI will usually get the job done on a residential system, but I usually have it up between 60-70. Just makes things go faster and does a little better job at making sure everything pops up.


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## ken-n-nancy (Jul 25, 2017)

SpiveyJr said:


> I had my lines blown out the other day and on some of the zones the heads would pop up squirt some water and then go back down before there was enough time to completely drain them. Has anyone heard of such a thing happening?


That shouldn't happen. Sounds like the compressor/tank system that was being used couldn't deliver enough volume at the needed pressure.

The issue isn't just the pressure delivered by the compressor/tank system being used to do the blowout, but a matter of how much pressure (pounds per square inch, psi) at what rate (cubic feet per minute, CFM) for how long. It usually takes a minute or so per zone, which can be difficult for some compressor/tank pairings to sustain for that long.


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## Mr McTurf (Jun 21, 2018)

ken-n-nancy said:


> SpiveyJr said:
> 
> 
> > I had my lines blown out the other day and on some of the zones the heads would pop up squirt some water and then go back down before there was enough time to completely drain them. Has anyone heard of such a thing happening?
> ...


I agree with the above. I guess my first question for Spivey should have been what kind of a compressor was used to blow out your system? Since you said you had it blown own by someone else, I was assuming that they were using a compressor with sufficient volume to blow out a residential system.

When blowing out, I usually run through each zone at least twice. The first time through I let it go for three minutes. The second time I go for another 2 minutes, and then take note if I think any particular zone needs more time.


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## Delmarva Keith (May 12, 2018)

I looked into blowing out systems but the compressor needed to do the job right is expensive. The minimum recommended was 80 CFM at around 40 to 55 psi. The least expensive compressor in that class that I could find that was trailerable was many thousands of $$$.

I'm told (and it makes sense) that using insufficient air volume will allow water to stay in the bottom of the lines with the air just flowing over top of it. That's OK because that would still leave expansion space for ice . . . unless there's not quite enough space and the pipes get cracked.


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## Rain Bird Corp (Jun 6, 2018)

Check out the rigs the pros use.
https://www.lawnsite.com/threads/compressor-picture-thread.484286/


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