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Thread: Blowing out main drain

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    Blowing out main drain

    Hi all,

    When blowing out the main drain how do you know if an airlock has been achieved? I blow out the drain using a compressor, let it bubble for about 45 seconds, but after I close the valve I still get some bubbling here and there for a while. Is this normal or is the valve not closing properly perhaps? This is the first time I've closed the pool myself and I really don't want to screw it up


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    Johnl's Avatar
    Join Date
    May 2008
    Montgomery County, PA

    Re: Blowing out main drain

    I think your OK. If you had a leaking value, you would be losing pressure and the weight of the water would force the air back into the pipes, instead of out of the drain.

    I'm not an expert, so hopefully others will weigh in.
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  3. Back To Top    #3

    Join Date
    May 2007
    South Central NJ

    Re: Blowing out main drain

    Most drain lines run horizontally before going up. This section usually refloods untill the rise in the line is above the drain. An air lock will prevent any further water from entering the rising pipe. That elevation is typically well below the frost line by several feet.

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  4. Back To Top    #4

    Re: Blowing out main drain

    Thanks for the quick responses.

    Gonna call it good and put the cover on.

    Thanks again

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