Boilers - Steam and Hot Water Systems - consequence of non-pump away?

Both of the black nipples and elbow from the circulator to the boiler on the return side are slowly leaking. I'm puzzled why it's leaking now and only in this section, when last year after installation I did not detect any leaks. I used pipe thread compound and tightened it down to what I thought was tight, but now these leaks have developed. The local hardware guy thinks I tightened it too tight. I was more concerned I hadn't tightened it enough and thought the compound should keep it from leaking if I hadn't. Is this a consequence of a non-pump away set up? Thanks for any suggestions.

Is this a consequence of a non-pump away set up?That should have nothing to do with your leaks.

Pipe dope isn't intended to prevent threaded joints that are insufficiently tightened from leaking. Dope does act as a lubricant that allows tightening connections with less torque - which in turn helps make the threaded connections leaktight.

I don't think your leakage is caused by threaded connections that are over-tightened. I haven't heard of that before. If connections are over-tightened, they will be difficult to disconnect in the future, but they won't leak.

I don't think you will find most pipe dope advertised as a "sealant."

There has been mention that the chinese fittings/pipes tend to leak. Some installers go as far as using both pipe dope and teflon tape. I recently did some work on the system here and ran into issues on a new part (made in china by a well known American company). The bottom tapping was not correct as a plug threaded into it stopped suddenly.

Not how a pipe thread plug should act. Used a pipe tap and ran it in a little until the plug acted as it should. Threaded in with a steady tightening of the plug.


The other side of your leak is that the fitting may have cracked. The taper in the pipe threads exerts a lot of outward force on the fitting. It just may be worthwhile to purchase new pieces and do it over.

Al.

I'd like to add that the threads, both male and female need to be pretty much 'squeaky clean' before assembly. If there are specks of metal or dirt on the threads, it can prevent getting that all important 'metal to metal' seal that you need. Use a wire brush on a drill to clean the threads.

If you elect to use that teflon tape junk, please only use ONE layer, (if you must use it at all), and keep it 2-3 threads back from the end of the male pipe. Using too much of the tape can also prevent a metal to metal thread seal. You THINK it's tight enough, but if you went back a day later and put the wrench on it ... SURPRISE! it's LOOSE again!

Keep the dope about 2-3 threads from the end also.

Typically, you want about EIGHT threads engaged in the fitting for a proper seal, but this is HIGHLY dependent on the sharpness of the taps and dies used to thread the pipe.

If the female fitting were cracked, I'd expect that would be discernable from the nature of the leaks. Since several joints are leaking, and from your description of your possible under-tightening I think the joints aren't adequately tightened. Either way, you'll have to disconnect and reinstall.

I do prefer USA-made fittings - my Ace Hardware sells them. But I've used Chinese fittings and haven't experienced any problems yet.

If you elect to use that teflon tape junk, please only use ONE layer, (if you must use it at all), and keep it 2-3 threads back from the end of the male pipe. Using too much of the tape can also prevent a metal to metal thread seal. You THINK it's tight enough, but if you went back a day later and put the wrench on it ... SURPRISE! it's LOOSE again!

I don't like teflon tape either. There are some places that it can be OK, but the stuff is mostly trouble. For hydronic systems I use Hercules Pro Dope on the fittings of 1/2" and larger. Then on small stuff like 1/8" NPT bleeders and such I use Loctite pipe thread paste (#565).

If you don't have a drill with a wire brush can also use a hand held wire brush. Takes a little longer but does the trick in clean up. Removes that evil teflon tape in a hurry too. Also degrease the fitting with some solvent. Many are still coated with cutting oil.

Note that my mention of the use of teflon tape was due to the (lack of) quality in the chinese fittings. Not an endorsement of the stuff.

Kinda' funny how over the years some items are brought out and pressed as being the "way to go." Then as folks gain experience with these products and they end up being actually "evil." Clear RTV is another one, bad stuff. Unless you are gluing glass together for a fish tank (although be aware of the RTV with anti-mildew compounds in it).

I could mention a few more items that are becoming prevalent in the hydronic business. Time will tell whether they had been worth using.

Al.

The only place I like teflon tape is a steel thread into a cast iron thread. What size pipe wrench did you use? I usually use 24" wrench.

The only place I like teflon tape is a steel thread into a cast iron thread. What size pipe wrench did you use? I usually use 24" wrench.The wrench size is certainly relevant. With experience, one goes by "feel," and even then I sometimes under-tighten threaded connections. And the "feel" and torque depends upon the the wrench size. My impression is that a male copper fitting into a steel female requires more tightening torque.

Back to teflon tape. In five years serving in my particular part of the Navy, teflon tape was forbidden. Being caught using it was just shy of a court-martial offense. And there would be a hullabaloo when an old joint was disconnected, and teflon tape discovered - even though the guilty party was probably long gone.

The Navy does not necessarily tell you all their reasons why to do, or not to do, something. My understanding was that there was a concern about teflon crumbs winding up in the piping system and maybe because teflon tape was considered a short-cut, ineffective, or who knows what.

A question poses itself: if teflon tape was forbidden, where did Navy machinist mates, et al, ever get it? Maybe from the guy who serviced the pop machine? Or maybe in installation kits from equipment manufacturers? Or smuggled in from the outside? Probably, teflon tape was listed in the DOD/Navy supply catalog, so maybe they just ordered it?

Yes, in that section they were all chinese made parts. I was a little concerned about that, but talked myself out of it. And if my memory serves me correct, on some connections they did seem to just stop. I used an 18" pipe wrench. I must confess I didn't make them "squeaky clean". oops! What type of solvent would you recommend to degrease it?

Yes, in that section they were all chinese made parts. I was a little concerned about that, but talked myself out of it. And if my memory serves me correct, on some connections they did seem to just stop. I used an 18" pipe wrench. I must confess I didn't make them "squeaky clean". oops! What type of solvent would you recommend to degrease it?

Today I think that denatured alcohol is the best bet for cleanup. Can use either latex or nitrile gloves for protection while using it. A paper towel or two and an old tooth brush helps in getting the cutting oil off the threads.

In the past I have used automotive products such as BrakeKleen (BrakeClean). There are two types available: chlorinated (red can) and non-chlorinated (green can). Note that the chlorinated is dangerous in the presence of UV. So even though the green non-chlorinated is less effective. It is also less effective in creating {very} harmful by products.

And gloves of course. Although the red can is tough on nitrile and eats latex.

Al.

I'm all for 'overkill' usually... but I'm not sure that degreasing the fittings is necessary? Sounds like an awful lot of extra work that may not be needed. Just thinking out loud...

That should have nothing to do with your leaks.

Pipe dope isn't intended to prevent threaded joints that are insufficiently tightened from leaking. Dope does act as a lubricant that allows tightening connections with less torque - which in turn helps make the threaded connections leaktight.

I don't think your leakage is caused by threaded connections that are over-tightened. I haven't heard of that before. If connections are over-tightened, they will be difficult to disconnect in the future, but they won't leak.

I don't think you will find most pipe dope advertised as a "sealant."

Seen lots of over tightened joints leak.
Gas supply pipes will leak easily if over tightened.

The fitting will stretch and not seal properly as the threads bottom.


WOW, never heard so many complaints with T-Tape.
Use it all the time, never any issues.
Never ever have I degreased a fitting.
I will wire brush a used fitting though.

I used to use hemp strands and brown dope, they never ever leaked even with prop. glycol.

I used to use hemp strands and brown dope

but you never inhaled, right?

Several years ago I re-tubed an industrial air compressor that had all the pipe fittings sealed with Teflon tape from the factory. That beast (it was 800 horsepower and rated at 3,000 CFM) leaked oil at the rate of about ten gallons a week. When I got done with the rebuild it leaked maybe a quarter-cup a week...from the one joint that I hadn't solvent cleaned the threads.

I used a Locktite product that I think was called Hydraulic Leak Lok. It was a red liquid that hardened in an anaerobic connection. I used a wire brush to clean every male thread and all female threads that were accessible. After that I used Brakleen or trichrolethylene to clean any trace of oil or grease from the threads before applying the Locktite product.

I use Teflon tape but quite honestly, it isn't the most wonderful product on the face of the earth as some would like us to believe. It's clean and easy to apply but far too often does not do the job. For an all-purpose thread sealant I prefer a Teflon paste product. Sometimes I will use both the tape and the paste.


The last fuel gas piping job I did (last year) I used all black steel pipe and fittings from Big Blue. I wire brushed all the threads (internal and external) and solvent cleaned them before using Teflon paste. I screwed them together using only moderate force. Absolutely no leaks and passed inspection with praise from the inspector.

Several years ago I re-tubed an industrial air compressor that had all the pipe fittings sealed with Teflon tape from the factory. That beast (it was 800 horsepower and rated at 3,000 CFM) leaked oil at the rate of about ten gallons a week. When I got done with the rebuild it leaked maybe a quarter-cup a week...from the one joint that I hadn't solvent cleaned the threads.

I used a Locktite product that I think was called Hydraulic Leak Lok. It was a red liquid that hardened in an anaerobic connection. I used a wire brush to clean every male thread and all female threads that were accessible. After that I used Brakleen or trichrolethylene to clean any trace of oil or grease from the threads before applying the Locktite product.

I use Teflon tape but quite honestly, it isn't the most wonderful product on the face of the earth as some would like us to believe. It's clean and easy to apply but far too often does not do the job. For an all-purpose thread sealant I prefer a Teflon paste product. Sometimes I will use both the tape and the paste.


The last fuel gas piping job I did (last year) I used all black steel pipe and fittings from Big Blue. I wire brushed all the threads (internal and external) and solvent cleaned them before using Teflon paste. I screwed them together using only moderate force. Absolutely no leaks and passed inspection with praise from the inspector.

I can appreciate that some of these "fancy" sealants need oil free surfaces to bond with otherwise they fail.
T-Tape does not need this.
The teflon pipe dope... read the warning on it sometime we only use it for gaswork as it is kinda nasty stuff..

I think there are many different way to do the same job :-)

Teflon tape does a poor job with any oils. Teflon paste, if listed for the purpose, usually does okay for oils.

Never use a thread sealant/lubricant that is not listed for use with whatever is being conveyed through the piping system.