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Caleffi air separator, sweat or threaded?

sunlight33 Member Posts: 330
Looking to add an air separator to my boiler loop, do you guys prefer sweat or NPT?


  • kcopp
    kcopp Member Posts: 3,736
    Its going to depend on how your boiler is piped. If the header is steel stick w/ threaded.... if copper then sweat.
  • Ironman
    Ironman Member Posts: 6,373
    I prefer press. 😀

    If you have an old style compression tank, don't add an air separator.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • mattmia2
    mattmia2 Member Posts: 3,177
    even if it is copper i would recommend threaded and adapters, especially if it is bigger than 3/4". That is a lot of mass to heat and you don't want to burn up a $100 part if something goes awry especially if you don't have a lot of experience soldering or a big enough torch to heat the boss attached to the body of the separator.
  • HomerJSmith
    HomerJSmith Member Posts: 1,304
    If you are sweating, do as hot_rod said in one of his Caleffi videos. Heat the boss and the pipe both because lead free solders differently than the older lead composition. I aim the flame so that it points away from the Discal body toward the pipe and heat both before applying the solder. I always move the flame around the boss and pipe. I use Oatey 95 flux and when it turns from liquid to a dry state, I apply the solder.
  • sunlight33
    sunlight33 Member Posts: 330
    edited February 14
    Thanks for the tip, I was a bit concerned about the heat might cause some damage to the plastic mesh inside.
    Edit: Or get the press version but I have to find out where to rent the press tool.
  • HomerJSmith
    HomerJSmith Member Posts: 1,304
    Solder one side and cool it down and then do the other side and cool that down. A wet rag or squirt bottle will do the job.
  • hot_rod
    hot_rod Member Posts: 14,797
    The media in the brass versions of the separator, dirt, air, and combo is about 3/4" away from the solder cup. The media only touches the brass on the bottom, you would need to get it smoking hot to damage the media, or point the torch directly in the opening :)

    Super simple to take the media out, it is a fine straight thread with an O ring on the "belly seam" you can actually hand tighten that thread and they will seal.

    We have seen the media get partially plugged from excess and improper teflon tape use, so knowing it is easy to disassemble is a good tip.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • PC7060
    PC7060 Member Posts: 330
    Make me want to take mine apart. Oh for one more isolation valve!
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