# add T to existing black pipe



## free75degrees (Aug 26, 2008)

Hopefully this is a stupid question and the is an easy answer...

I have a problem - I need to add a T to a section of existing black pipe and the I have no idea how I can do it without disassembling my entire setup.  The T needs to go in a section of straight pipe that is between 2 90 degree turns.  I can easily cut into the straight section, remove the two halfs of the straight section and get them threaded, then attach the T to one of the sections, but then there is no way to tighten the last connection.  Tightening one part will loosen another part!  Is there some magic I can do to get around this?


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## DenaliChuck (Aug 26, 2008)

Are there reverse thread fittings available so turning the fitting would tighten both sides?


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## gorsuchmill (Aug 26, 2008)

union?


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## free75degrees (Aug 26, 2008)

Does a union have reverse threadings?  If so, when I go to Home Depot to get my pipes threaded at custom lengths, will they be able to thread in reverse?

I know the plumbing guys are probably laughing at me.


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## Eric Johnson (Aug 26, 2008)

A regular union should work. It's just a compression fitting tightened with a big nut that brings the two halves together. You put a nipple into each side then pull the whole works together with the big nut. No need for reverse threads, though I think they can make something like that with the pipe threading machine if you really want it. I'd go with the union.


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## kabbott (Aug 26, 2008)

No reverse threads. A union will use two shorter regular thread nipples, the union comes in two pieces with a tapered seat and a nut that clamps them together.
You will still need a little flex to get the union on, but not much if you can back one elbow off a bit install union and then rotate elbow back up.


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## Nofossil (Aug 26, 2008)

> I know the plumbing guys are probably laughing at me.



... snort - hee hee - gasp.... Oops - didn't realize the mic was on.....

A union allows you to thread each side independently, then connect the union. A flange pair will accomplish the same thing.]


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## kabbott (Aug 26, 2008)

Thats to funny......all three same time


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## Eric Johnson (Aug 26, 2008)

Yeah, but I was first.


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## BrownianHeatingTech (Aug 26, 2008)

You can also, if you really want to, drill a hole and weld a nipple into it, building your own tee.

But a union is the easier way to do it.

Joe


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## Nofossil (Aug 26, 2008)

I remember watching a bunch of Dutch guys putting in a steam heat system for a greenhouse. No threads at all - they just weld every joint. Faster than I could screw together a threaded fitting,, too.


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## BrownianHeatingTech (Aug 26, 2008)

nofossil said:
			
		

> I remember watching a bunch of Dutch guys putting in a steam heat system for a greenhouse. No threads at all - they just weld every joint. Faster than I could screw together a threaded fitting,, too.



Yup.  A good pipe welder can get a lot more work done per hour than someone using threaded fittings.

Of course, a good pipe welder costs more per hour, so unless it's a big job and the speed will make up for it, threaded fittings are still king around here.

For larger pipes, grooved fittings are very nice...

Joe


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## free75degrees (Aug 26, 2008)

Cool, thanks!  I'm gonna pick up some unions tonight.  Now I can laugh at the next guy who asks that question.


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## Eric Johnson (Aug 26, 2008)

One union is all you'll need.


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## chuck172 (Aug 27, 2008)

a union and a nipple.


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## free75degrees (Aug 27, 2008)

Eric Johnson said:
			
		

> One union is all you'll need.



oh, I meant one union for the oil boiler outlet, and one for the oil boiler inlet.


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## chuck172 (Aug 27, 2008)

Carefully measure end to end a new union, nipple, and tee. Figure out what they will take up. Mark center of where you want the new tee. Remove the two sections of piping, shorten, re-thread,  and re-install with the new pieces. Then just tighten the male and female union parts together.
Then hope you don't get any leaks.
It may be easier to cut out an existing piece of black threaded pipe leaving male threads. Put in a piece of copper with CxF adapters, sweat in a new piece of copper, then easily cut in your tee.


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## markpee (Aug 27, 2008)

This post brings to mind a question that I've not had time to research - is there such a thing as a 4-way T for 1 1/2" black iron pipe?  This would make my install so much easier on the supply side of my boiler, as I wouldn't have to slice 11 zones of copper!


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## Eric Johnson (Aug 27, 2008)

I bought a 3/4-inch black iron 4-way tee recently at Lowe's. I assume someone makes one in a 1.5" size, but you def. have to go to a plumbing/heating supply house to find one.


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## in hot water (Aug 27, 2008)

Victraulic and others make a saddle that connects to the pipe with a U bolt or two.  Use a hole saw to make the hold, align the saddle, and screw in the connection.  You see them in fire sprinkler work all the time.  The are also used to connect onto water mains. Check about temperature rating.

 hr


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## chuck172 (Aug 27, 2008)

A four way tee is called a "cross".


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## Eric Johnson (Aug 27, 2008)

A black iron cross sounds like a Goth accessory.


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## Stlshrk (Aug 27, 2008)

http://www.pexsupply.com/categories.asp?cID=182&brandid;=

iron crosses up to 2"


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## free75degrees (Aug 27, 2008)

As an alternative to a union, would a pair of taco circ flanges without the circ in the middle work?  Just put a single gasket in the middle and bolt them together.


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## Stlshrk (Aug 27, 2008)

Yep, they make things serviceable as well.  The gaskets can be replaced.


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## BrownianHeatingTech (Aug 27, 2008)

free75degrees said:
			
		

> As an alternative to a union, would a pair of taco circ flanges without the circ in the middle work?  Just put a single gasket in the middle and bolt them together.



Yup.  Just more likely to leak.  I've done that where installing a union was impractical (down in a hole where there was no way to get a pipe wrench on a union - a ratchet and extension easily tightened the flange bolts from outside the hole).

Joe


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## mtfallsmikey (Sep 2, 2008)

What Eric referred to is known as a Dresser coupling


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