Closely space tees

[Deleted User]

and mostly to THIS choir...

Been meaning to talk to you about your opinions on di-electric unions, but need to find some pictures first..

ME

Singh_4

For the masters.

I just looked at an install , where the other/s contractor are no longer involved.
I commissioned a Munchkin 199 with vision 1 package.
Homeowner/GC bought boiler at supply house (that I DON'T) have an acount with. Anyway,
He called me because apparently I am the only other guy in the area using multicor, and the original guy used multicor in the slab, then walked. (I know him, he is good and a FAP)
Second guy pipe boiler, but could not make the connections,and that's all of the story I got.
It was clear he did not know how to control or pipe the boiler, like using manual set mixing valves , they are not needed, but he did do a very neat job.

My obvservations are this, his pri/sec tees seemed wrong to me, but it may work

He piped them like a sideways H

what do you guys think ? I would think the primary would need to go into the bull of the tees.
Sorry I forgot my camera.

Brad White_9

Do I gather that the

main flow goes via the branch and the "diverted" flow goes staight, Devan? If so, that will impose flow in the secondary regardless of need. The velocity head and the resistance of a 90 degree turn within a tee will assure that (assuming I understand your situation correctly).

Singh_4

like this

1 1/4"
secondary supply ________________________ primary supply

|
|
| 3" nipple
secondary return ________________________ primary return

1 1/4"

Singh_4

picture this

a 1 1/4" black tee with a 3" nipple screwed into the bull
and the second tee screwed into the other end of nipple on the bull.
pri. on one side sec on the other.

My thinkings were the same flow would go right thru, that three inch nipple
is just a by-pass now?

Brad White_9

I think I see...

By "bull" you mean the branch outlet, right?

(Bull is not a term I use regarding tees. Salesmen, yes. Tees no.

If I see this right, where are the next pairs of tees, how far apart? What controls flow through this bypass?

See attached, to see if I got this right.

Uni R_2

Like This?

Singh_4

you got it UniR

Except , Boiler supply and heating supply on the same tee, same goes for the return.

That's a nice drawing, where can I get that snazzy program?

Brad , almost, but primary s&r on same side .
Sorry, bull is what us plumber's call the middle outlet of a tee, don't ask me why.

Uni R_2

MS Paint?

Hrmmm... I'll sell you a copy. ;-)

I think it would work fine provided the flow checks didn't fail, since the Munchkin primarilty needs P/S piping for HX flow.

Brad White_9

Not unlike

the Taco LoadMatch (tm) tees, is it?

I do like the simplicity.

Thanks for the bull edumacations, Devan! New one on me. (Bull tee is more a term of converging flow, head to head and exiting the branch. May be some similar origins to your term.)

Brad

Singh_4

may work

until the heat side circulators come on then , the munchkin's circ is now in series with them. As there would be an easier path than going back to HX . And no flow thru that 3" nipple,No?
By piping into the "bull" of tee you not only isolate circs from each other, but required flow will go back to muchkin.

Uni R_2

LLHs work...

This design isn't much different than a LLH. If there is a difference in flows between the two circuits, the circuit with the higher flow rate will short circuit through the tee.

Singh_4

LLH

I knew the LLH may come up, big difference is the large diameter of the LLH which would reduce vertical flow ,and the short distance between upper and lower ports on the LLH ,creating a mini buffer which would un-couple the circs from each other.

What was pipe was all 1 1/4" , I can't see how it would be the same as a LLH.
This is why I paused at what I saw today, it may work, but...
could we save a bunch of $$ by making or own LLH with two tees and a nipple..
don't think so.

P.S Good article from Siggy this month about LLH's and pri piping.

Jed_2

Bull Head Tee's

are only "bull" head if the "branch" is larger than the runs. Think of a good ole "Texas Long Horn"; are his horns as big as big his snout? Everywhere I've been, that's a "bull head tee". Everything else is just a tee, or reducing on the run, or the branch.

Jed

Singh_4

dont give me no bull

: )

your right a bull headed tee has a larger middle branch.
it also proves and is correct to say the middle branch , regardless of size
is call the bull outlet or inlet of a tee.
I'm not saying the full 1 1/4" tees in question are called "bull headed tees", but the "bull outlet of the tees"

[Deleted User]

Running Bull...

makes absolutely NO sense...

You have the RUN (straight flow thru) and the bull (like a bulls horn..)

Technically speaking...

What you speak of in the case of the flow coming IN to the side branch and going in opposite directions from there can be done with all three ports the same size. In other words, a bull headed tee.

In any case, bull headed tees have NO place in a hydronic system unless used as a diverter tee (directional pumping) application. Given to its own destiny, the flow through the two outlet branches will almost ALWAYS be hunting, looking for a point of equalibrium, and never find it. Flow rates keep changing between the two outlets.

Siggy wrote about this in one of his first articles in P&M magazine. Said you should not do it.

I don't.

ME

Dave_4

No no no

Mark, that's the intended path for a condensing boiler - coldest water back possible and this helps. The bull headed tees aren't blocking flow at all - they aren't even a factor. They serve a pressure differential bypass pipe that is more than big enough to provide a hydronic break between the circs on the two circuits. I can't see why it wouldn't work just fine.

[Deleted User]

Won't work...

Uni, my guys inadvertently piped a system this way a few years back. It doesn't work right. ANy time the boiler fires, I get unwated flow into secondary circuits that I didn't need and didn't want.

As Devan said, you end up essentially with pumps in series with each other. THere is enough "throw" on the fluid to the point that you get flow where you don't want/need it. If you've designed it that way, then its OK, but if for example, you have primary/secondary with VSI between the two loops, it will spill unwanted heat over to the secondary when the primary is running.

In order to get complete and proper hydraulic seperation using piping as opposed to LLH, the primary flow must go through the runs of the tees, and the transfer circuit through the bulls of the tees, and there should be at least 5 pipe diamters of straight pipe before the first tee, and 7 pipe diameters of straight pipe after the second tee. Otherwise, you'll get flow where you don't want or need it.

I know that in your minds eye, the method you drew SHOULD work, but in reality, there are other things at play that will fiddle faddle you with the fickle finger of fate...

Been there, done that, thought it ought to work, but it doesn't.

See attached dwg for clarification.

ME

Dave_4

Mark...

Would you pipe that VSI circuit on a system with a condensing boiler?

I said "no no no" because it sounded like you were saying that the bull headed tees obstruct the flow. We're all on the same page, just different parts of it.

Devan, does it work?

[Deleted User]

Depends...

But probably not. But then again, not everyone that uses P/S piping uses mod con boilers.

Just trying to keep people from making the same mistakes I've made in life:-)

ME

Mark Wolff_2

Tees

Bull head tee's have the larger middle/branch outlet. Bull outlet of the tees is not correct. The side outlet of a tee is not referred to as a bull outlet. Bull only refers to that location in the specific application referred to as a "bull-headed" tee, for the reasons stated in another post.

Mark Wolff_2

Wow!

Nice literation... fiddle faddle fickle finger of fate. Are you a preacher too? That was quite the string, nice job.

Singh_4

Disagree

A bull headed tee has larger outlet than run, agree.
When you pipe the supplying fluid into that branch and not the run,
you are piping it into the bull or like a bull headed tee , regardless of size.
But that same outlet becomes a branch if the supply goes into either run and exits out of the other branches.
Therefore , it is commonly called the bull , by many, at least around here, I was taught and been calling it that for 20 years, probably by someone else you called it that for 20 years.
And , I'll keep calling it that for another 20 years.

Brad White_149

Branch and Run

were the terms I was taught. The "bull" term makes sense as an additional descriptor the way you put it.

Thanks!

Singh_4

does it work?

Well, after I pointed out the piping defects,(or the way I would have done it) the owners eyes glazed over. So I guess it will work good enough for him.
The manifolds got hot, the unit ran.
But since I was the last guy to touch it, and if there ever was a problem guess who he gonna call, guess what I'm gonna say.

Uni R_2

That's the sad truth...

Devan, I don't envie you in those situations.

Mark Wolff_2

talk

You can email me anytime. wolffmechanical at hotmail dot com

Mark Wolff_2

bull

Fair enough. As a side note, the "bull" or branch tapping on a tee cannot be used as the supply side inlet on heating systems for anyone using the IMC codebook. Supply has to enter on the run of the fitting.

Singh_4

Except

when piping close spaced tees for pri./sec , : )

Mark Wolff_2

???

In practicality yes, in code, no. There is no exception written for it.

Maybe someone here is on the BOCA, ICBO, or SBCCI boards and could suggest changing it???

IMC 1206.1.1 Prohibited tee applications. Fluid in the supply side of a hydronic system shall not enter a tee fitting through the branch opening.