Irrigation Blowouts, PSI and Back Flow Preventers.

Discussion in 'Irrigation' started by White Gardens, Sep 22, 2012.

  1. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    That's right! If you aren't doing something right, then don't do it at all.....

  2. CAPT Stream Rotar

    CAPT Stream Rotar LawnSite Fanatic
    Messages: 6,202

    are the systems pvc or poly there?
  3. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    PVC main-lines and poly leaders to the heads.

  4. Irrigation Contractor

    Irrigation Contractor LawnSite Senior Member
    Messages: 424

    It is hard to tell your specifics without putting eyes on it, but if this property was winterized in the past and it had no freezing problems then you should not have a problem.

    Sounds like you have the compressors setting down, but staying under 80-85 psi is good.
    - Make sure all water sources are turned off and the main drained down.
    - Locate the blow out connection, so just cut a tee in or a quick coupler.
    - When you first put air to the system, have a valve blow open by the clock or manually.
    - If it is a big system, we blow the last valve to flush the main to speed up the zones and to avoid reversion or holding water is sections of the main.
    - Take a small hand pump since at times you will have to pump out the water that does not drain from air or naturally.

    In the end, do not be a afraid to cut a tee or drain in if you feel it is needed. On our large commercial systems, we will shut the system down, let it drain and then come back to blow the lines. Makes no sense to put thousands of feet of large main with the compressor and I feel it is much less strain on the pipes.

    Someone may have mentioned this, but one major thing to remember is the air from the compressor is going to be HOT. So combine hot air with cold pipe and rubber gaskets you can do some damage.
  5. Mdirrigation

    Mdirrigation LawnSite Gold Member
    Messages: 3,794

    Before you turn on the compressor make sure a zone is on , and turn off the compressor with the last zone running . you will never have a problem as long as you dont charge the main , always have a zone open or on .
  6. BrandonV

    BrandonV LawnSite Platinum Member
    Messages: 4,631

    we don't blow things out around here but I have a new account that is an industrial complex and the the lines are much shallower than I'd normally have them because of all the other underground utilities. I don't have one of these big pull behind compressors but my truck has 4 air tanks and a glad hand connector on the back for the trailer brakes I think I may try hooking it up to it and see what it can do.
  7. 1idejim

    1idejim LawnSite Fanatic
    Messages: 11,358

    that air would be pretty dirty.
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  8. Mdirrigation

    Mdirrigation LawnSite Gold Member
    Messages: 3,794

    I dont think you have enough air on the truck , we tried running a impact gun off the glad hands of a peterbilt , it wasnt even close .
  9. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    Thanks for that tid-bit! Thumbs Up

    When I'm done, I might cycle all the valves to ensure that there is no pressure to be on the safe side.


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