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  1. #14
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    16,505
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    These trade schools need to start teaching real world stuff instead of all the BS.

  2. #15
    Join Date
    Aug 2009
    Location
    Beatrice, NE
    Posts
    6,670
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    Your blow back comes from both the hose and the access fitting. The hose is refrigerant left in the hose, the access fitting is refrigerant that slips past the seal that is no longer tight while you are spinning the nut off.

    The ball valve will eliminate most of the release from the hose but you need to remember what refrigerant was last in that hose before connecting to the next system.

    The access fitting is best eliminated by using proper disconnecting practice. Not much you can do when connecting as it is what it is. When disconnecting push in on the stem of the hose to hold the seal against the fitting, then spin the nut. Once the nust is spun off the fitting then let up on the stem quickly and you will have very little release. The only issue here is on some brand and some installations there is not enough room to get hands in there to do this.

  3. Likes 3.14, mixsit liked this post
  4. #16
    Join Date
    Sep 2006
    Location
    Ohio
    Posts
    709
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    This is why we shouldn’t drink excessively before posting a question.

  5. #17
    Join Date
    May 2018
    Location
    Central Florida
    Posts
    194
    Post Likes
    To minimize blow back while hooking up or disconnecting from the system.... make sure your Schroeder vale stem depressors depth is set properly.... enough to depress the stem.... but not so much where it takes multiple turns for the hose to seal when being put on.

    I will not buy hoses without ball valves for the following reasons:

    Prior to disconnecting off of the equipment, remember most of the refrigerant in your liquid side hose will be liquid. If you shut the liquid hose ball valve near the unit down, then open everything else up wide, you can boil all of the liquid in any hoses or your gauges off into the suction side. This may not be a new concept to you, but it minimizes loss and is just good practice. This is assuming you have purged hoses when hooking up to the system... if not that’s a good way to introduce air into the system.

    The second reason I prefer valves is my gauges have a built in micron reading in them... with a ball valve right next to my vacuum pump as well, I can easily shut it down without turning off the vacuum pump or main gauge valves and get a really quick picture of vacuum level. You can also quickly isolate just your gauges, hoses and the pump to check for gauge or hose leaks.

  6. Likes mixsit liked this post
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