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Leak on Single-pipe return

FizzFizz Member Posts: 360
Daughter has small leak on return pipe; what is best approach for replacement?


  • Jamie HallJamie Hall Member Posts: 7,540
    In my experience, small leaks get bigger. And multiply. The best thing to do is to take the section of pipe out -- including that coupling -- and replace it. I don't know where the other end of the pipe -- to the right in the picture -- goes, but I'd be inclined to take it out from the elbow on the left at least to the next fitting on the right.

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 3,283
    I would take a sawzall or a grinder with a cutting disk (ware goggles or face shield) and cut directly through the middle of the coupling.

    also cut the pipe near the elbow and remove the pipe. Take the angle grinder and slice the remaining half coupling (on the right) along it's length. Don't cut into the pipe threads but cut as deep as possible. Drive and old screwdriver into the cut and open up the coupling so you can remove it.

    Remove the old elbow the same way. Clean up the old threads by running a die over them. Then replace with a new elbow, a union and a new pc of pipe

  • FizzFizz Member Posts: 360
    Now I have direction, thanks!
  • mcgee45mcgee45 Member Posts: 7
    I might be dealing with the same leak, sounds replacing is the best thing to do indeed.
  • FizzFizz Member Posts: 360
  • j aj a Member Posts: 1,758
    Replace as much of it as you can, if that's a first floor radiator, simply disconnect it an work back ,the measures are already done for you...
  • fusionmanfusionman Member Posts: 3
    From your picture that sure looks like a thread protector and not a coupling.
  • gerry gillgerry gill Member Posts: 2,734
    you right Fusionman. But in the east guys have used them for couplings forever. I'm not saying its right,`- my guys arn't allowed to used them.

    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • FizzFizz Member Posts: 360
    What's the advantage of a coupling v thread protector?
  • JUGHNEJUGHNE Member Posts: 3,833
    Fizz, there is a another discussion about "Thread Protector" down on the page, for you info.
  • ChrisJChrisJ Member Posts: 8,696
    Fizz said:

    What's the advantage of a coupling v thread protector?

    As far as I know, a thread protect is a thread protector, put on a pipe to protect the threads during shipping.

    A coupling is made to join two together. :)

    A thread protector in general doesn't have tapered threads. A coupling does.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

    Steam system pictures
    Central air project pictures
  • FizzFizz Member Posts: 360
    Thanks guys!
  • MilanDMilanD Member Posts: 1,074
    Yep. Thread protectors are prone to fail at some point and perhaps sooner than regular couplings... esp. on a gas line when someone used a hardening pipe dope. Ask me how I know... granted it lasted 60+ years, but it's a pita when you are the new(er) owner of said property and have to completely repipe some 80 feet of black iron, as every single one of them merchant couplings started leaking, conveniently tucked away behind and above hot air registers requiring them all be removed... over a Thanksgiving weekend... ugh... new fittings received both the yellow Teflon tape AND non-hardening pipe dope, and a mandatory -8 turns into new fittings...
  • JUGHNEJUGHNE Member Posts: 3,833
    Was the pressure changed from ounces to pounds for the inside piping recently?
  • MilanDMilanD Member Posts: 1,074
    JUGHNE said:

    Was the pressure changed from ounces to pounds for the inside piping recently?

    No changes as far as I know... oz of pressure is standard for what I am aware of... I then also ran cst as there was no way to get to some of the pipes without essentially having to redo even more of the heating ducts too - I had to measure for capacity making sure it's sufficient on the length and size, install bonding clamps, 6ga wire into the electric board... it took me 30 hours to get it fixed plus a materials run all over the town - Thanksgiving weekend and not one supplier had all I needed...

    At any rate, after repiping, I had to pass 10psi test for 10 min before utility would reconnect the meter... had to also replace all those old oil-seal brass service valves on all appliances (4 furnaces, 4 stoves and 4 gas DHW). Gas smell in the basement was amazing - I never smelled it that strong anywhere - EVER. There was at least 10 couplings (well, and els for that matter) that all failed at the same time, on 3 separate gas lines... dried-out dope and underthreaded pipes - original installers did maybe 5 turns at the most, and some pipe didn't even have more than 6 threads threaded on... The worst offenders were merchant couplings... goose-neck gas leak detector on them merchant couplings was flashing like it was a national emergency!
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