Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Boiler Nipple Replace

jtonzola Member Posts: 48
Hope everyone is enjoying their summer. I want to replace this nipple that is entering into the boiler from a return line because it has a slow leak. I know some of you have said that it may be difficult because the pipe might be locked in there because of the high heat over time.

Is it possible to change this pipe without cracking the actual boiler? I can see about 3 or 4 threads on the nipple as it enters the boiler. If so I was going to heat it up with a torch and try to turn it.

Thanks for your help!


  • jtonzola
    jtonzola Member Posts: 48
    Thanks Hatterasguy. Do I have to heat pipe then let cool each time I add a bit more PB or Kroil?
  • jtonzola
    jtonzola Member Posts: 48
    Okay and one more question. Do I heat it up again once I am actually trying to get the pipe out?
  • jtonzola
    jtonzola Member Posts: 48
    Awesome. Thanks!
  • jonny88
    jonny88 Member Posts: 1,139
    If it was me I would cut out nipple on the thread close to boiler.Make one or two cuts in nipple being careful not to go into thread of boiler.Hammer and small chisel to hit of section of nipple you cut the it will will come out easy.Good luck.
    ChrisJRoohollahPaul S_3delta T
  • gerry gill
    gerry gill Member Posts: 3,058
    we do what jonny88 said, We call it cut & peel in our shop.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

    JUGHNE Member Posts: 10,568
    One thing I do before the PB or Kroil is to use a dental type pick and cut the old pipe dope out of the threads right at the boiler.
    I believe this give the penetrating oil a better chance to get inside.
    If after multiple oiling's you try the long wrench and the pipe egg shapes then the cut & peel process is next.

    Leaving the tee connected to the outer end helps prevent the pipe from collapsing or egg shaping. Actually I would try to pipe wrench the tee first,, it has more meat and the nipple may follow. If not then leave the tee tightly on the nipple.
    If the nipple is distorted then it may become tighter in the boiler and less chance of unscrewing. If you ask 5 people how to do this you will get 10 methods to try. ;)
  • jtonzola
    jtonzola Member Posts: 48
    Thank you. These are great tips. I will be working on this this weekend hopefully.
  • Jason_13
    Jason_13 Member Posts: 304
    I have always done the cut and strip as someone called it. It is a 20 minute job and no real muscle required. A good sawsall blade. I did have a few I cut a bit to deep. A little Expando took care of that. Used to use lead wool but can't get that anymore.
  • Robert O'Connor_12
    Robert O'Connor_12 Member Posts: 728
    There is no way I would put a wrench on that. Cut & cape is the way to go.

    Robert O'Connor/NJ
    jonny88JackmartinPaul S_3delta T
  • Jackmartin
    Jackmartin Member Posts: 196
    Please do not, I repeat, crank on that nipple with a four foot wrench it is a sure way to crack the section. The only way to remove the nipple and not replace your boiler is to cut the nipple with a hack saw and hammer the threads in at the cut close to the boiler section the threads are thin at that point and will easily fold in. The main reason people run into problems cutting and scarfing ( that is the correct word for this operation) lies in the fact that they are over zealous with the saw and they damage the threads on the boiler section. Just be careful and take your time, and it will come out without damage to the section. We had a young fool of an apprentice that decided he was going to remove this nipple with a twenty -four and a twenty foot pipe; needless to say, we had to hammer the section out and shorten the boiler up fortunately it was an old Crane and had thirty sections to it. The boiler was firing at 2.5 million, so lose of one section, was not a big deal. Any old boiler is delicate, even if it looks like it could take a hard hit -- they are all made of cast iron and they will shatter like glass. I would suggest if you are not a boiler person you farm it out to someone with experience, it will be cheaper in the long run --boilers are not cheap to buy

    Jack Martin
    Winnipeg, Canada
  • jonny88
    jonny88 Member Posts: 1,139
    cut and cafer is how we call it.That young fool of an apprentice should have been stopped before he approached the problem.Gerry calls it cut and peel I never knew there was a correct name for it.Every day is a school day.
    JUGHNE Member Posts: 10,568
    It looks like the cut and scarf is the more favorable approach.

    What would you guys do to remove a 2 1/2" plug from the side of a boiler........14 years old. I did get the plug out of a malleable tee on the other side, for skimming. It was a chore with PB, then torch and 4' wrench. It was probably not buried as deep as the plug on the other side.
  • Fred
    Fred Member Posts: 8,541
    I don't know but it looks like there is some rot through on that boiler end section too, around the perimeter of that nipple.
  • jonny88
    jonny88 Member Posts: 1,139
    Cut face of plug of with sawzall or grinder then cut and cafer,yes you can.
    JUGHNE Member Posts: 10,568
    IIRC someone suggested using a hole saw on a plug, large as feasible I assume. Anyone try this?
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Cut and peel. It's highly likely the boiler threads will rip if you crank on the nip.
  • SWEI
    SWEI Member Posts: 7,356
    Fred said:

    it looks like there is some rot through on that boiler end section too, around the perimeter of that nipple.

    If indeed that turns out to be the case, I'd be looking for either a master welder or a top notch epoxy guy.
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,225
    First thing I typically do is soak the threads with kriol. Then cut the pipe leaving about 2-3" sticking out. Then i insert a short piece of steel pipe or nipple or fitting or whatever i have to keep the pipe from collapsing. Then i get on it with a 3' pipe wrench and a few grunts later with some special words in the mix, it usually comes loose. Sometimes it helps to rap on the pipe with a hammer while applying torque. I've successfully used this method on (almost rusted through) pipe threaded into old cast iron waste lines and plenty of boilers.

    If that doesn't work, I cut and peel.

    So there's another approach for you.
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,225
    Everything that helps even a little bit, I'll take it.

    Experience, learned the hard way, also helps a great deal. It helps educate a person on what they are looking at and what is likely the most successful method based on the conditions. I use heat sometimes as well, but very carefully when dealing hollow pipe threaded into cast iron. Cracking the cast from to much heat and pipe expansion would equal a total fail.
  • jtonzola
    jtonzola Member Posts: 48
    Wow. Thanks for all the comments. Sorry I have not been online for a while. I had trouble resetting my password. My father and I replaced that nipple in the summer. We cut into the pipe and then chiseled it out. I wish I remembered to take a picture. The nipple was completely caked with sludge and there was a lot of sludge in the bottom of boiler which we blew out with a water hose. Everything is back together and working pretty well. But I made some more recent discoveries with recalibrating pressurtrol which was helpful and now figuring out more. Keep you posted. Thanks again. I will post a pic of the new nipple.