Well pressure tank: fittings leaking

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by jbrukardt, Jul 1, 2013.

  1. jbrukardt

    jbrukardt New Member

    Messages:
    24
    Location:
    Maryland
    I recently replumbed my well pressure tank, and its pretty clear that i've universally done something wrong with my threaded fittings.

    I had a number of CPVC slip fittings which are dry and not leaking at all, but every metal to metal (brass) fitting, and plastic to plastic fitting is leaking very slowly.

    Pictures:
    Fitting 1: [​IMG]
    Fitting 2: [​IMG] (this is the worst offender)
    Fitting 3: [​IMG] (cant tell if condensation or drip)
    Fitting 4: [​IMG]
    Fitting 5: [​IMG]

    I know i did some of this wrong, after researching, and im going to have to redo it all. But i want to redo it right.

    Heres how i did every threaded fitting, whether plastic or metal:
    1) Wrapped threads with teflon tape, starting at the top side (where the hole is) and moving backwards down the fitting, at least 6 wraps per fitting, probably on average 10. Then a small small amount of pipe dope, in case the threading wasnt enough.
    2) Plastic to plastic fittings, and plastic to metal fittings were hand tightened as tight as possible (is it possible i may have overtightened?)
    3) Metal to metal fittings were tightened with a wrench until snug.

    Problems i see:
    • I put too much tape, tape where not needed, or pipe dope where not needed, thus ruining the fittings integrity
    • I overtightened some of the fittings

    Can you all help me out so when i take it apart and do it all over, i wont do it wrong again?

    Three types of fittings:
    • Metal to metal (brass)
    • CPVC to metal
    • black barbed poly fitting with female threaded end to CPVC male threaded
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,412
    Location:
    Bothell, Washington
    If you hand tightened the fittings, they may be too loose.
    I would have used two sets of pliers on them.
    Or pipe wrenches.

    It looks like you have plenty of pipe dope there.
    Sometimes Tape is a little easier to seal.
  3. jbrukardt

    jbrukardt New Member

    Messages:
    24
    Location:
    Maryland
    I really cranked them down by hand. From what i read, CPVC and other plastic fittings shouldnt be more than hand tightened + 1/4 turn due to thread taper, as if you do you'll crack the threads?
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,313
    Location:
    New England
    You likely need a bit more torque than hand-tight plus a 1/4-turn...it becomes problematic with female threaded fittings, since if you get them too tight, they are likely to split. It isn't as big a problem with male fittings. Unfortunately, with threaded fittings, you need to cut and redo a lot of it now. You can use the belt and suspenders approach and use both pipe dope and tape, just make sure the pipe dope you use is safe for plastic, not all are.
  5. jbrukardt

    jbrukardt New Member

    Messages:
    24
    Location:
    Maryland
    it should be obvious if i split the fitting id hope, so i when i refit i will crank them down good with a wrench and not be overly cautious like i was. Brass to brass fittings should be able to be cranked down very hard, right?
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,235
    Location:
    Cave Creek, Arizona
    TPFE, not Teflon, tape has some thickness. If you overdo the amount, such as 10 wraps, that extra thickness has to go somewhere, usually between the threads preventing the two surfaces to mate together, AND stressing the joint.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,313
    Location:
    New England
    With the normal tools a homeowner has, it's hard to overtorque a metal-to-metal tapered pipe thread connection. Doesn't mean you need to get it super tight to be water tight, though. And it doesn't mean if you are super strong and are using a very large tool you can't split one, but it generally is hard.
  8. Hairyhosebib

    Hairyhosebib New Member

    Messages:
    173
    Location:
    Arizona
    You might buy a roll of teflon tape for gas fittings. it is yellow in color and much thicker than normal thread tape. I am no fan of mixing metal and plastic threads. You should be careful of getting the thread started right or you could cross thread it. It can get ugly.
  9. jbrukardt

    jbrukardt New Member

    Messages:
    24
    Location:
    Maryland
    when i redo it, im going to try to transition everything over to brass-brass as best possible. Im having trouble finding 1 inch brass transition fittings though, especially in polypipe barbed > NPT female (found a male, but then cant find CPVC slip to 1 inch NPT male).
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