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Buderus gb142 dielectric union above low loss header

JJTraxx Member Posts: 33
I have a gb142-30 that was installed about 10 or 11 years ago. It's been good. I now have a very slow drip from the left side (hot?) dielectric union only when the system is at its coldest... Overnight. I happen to have a leak detector right below the header on the floor. It went off last night. The union has some visible iron looking rust coming out of the lowest part of it. Best suggestions and practices for replacement? The boiler also supplies my hot water to my indirect tank. Thanks in advance. 


  • Big Ed_4
    Big Ed_4 Member Posts: 2,706
    If you are talking about the brass nut right out of the boiler and connects to the low loss header . It is a compression fitting with a plastic feral . Buy a set of new adaptors to repair incase you make it worse by trying to tight up . To replace the set the manifold needs to be cut loose and dropped, or the boiler needs to be raised.
    I have enough experience to know , that I dont know it all
  • GW
    GW Member Posts: 4,679
    Good news Bad news—-you may not struggle to make the repair or it may jam you badly. We have experienced all of the above 

    There’s two or three generations of the GB142 boiler to low loss header Union style. 

    Supply house has these parts 
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,726
    Ferrule.......Feral is a wild 😜 Animal...Sorry Ed...had to ha ha 😂 🤣 😆 😅 😄 Mad Dog 
  • kcopp
    kcopp Member Posts: 4,395
    I have had to wrestle w/ a couple of those. I ended up using an oscillating tool w a metal blade to slice them off and replace. In one case I just removed it and placed in closely spaced tees...
    IMO it was not a great design.
    Big Ed_4
  • dko
    dko Member Posts: 562
    Which header do you have

    The black iron one you'd probably only need a new gasket unless it just needs tightening.
  • Big Ed_4
    Big Ed_4 Member Posts: 2,706
    Agree my spelling is bad :)
    I have enough experience to know , that I dont know it all