Drop header question.

Jon S.

How would I pipe a drop header for the Burnham V8? Burnham tells you to pipe up 24" 90 then 18" to the next 90 (the 18" is throwing me off). All the drop headers I've seen here look alot tighter than that. How do I follow piping recommendations and still do a drop header?
Thanks,
Jon

Ken_8

Are you,

confusing a true two-riser drop header with a two-riser non-drop header (near-boiler-piping) arrangement?

And what is rationale of even contemplating a drop-header in the first place?

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Steamhead

Ken, he's probably concluded

as I have, that a drop header will dry the steam better and is much easier to assemble than a standard header.

Jon, Burnham is the only manufacturer I've seen that provides drop-header piping diagrams (ya listenin', Columbia, Dunkirk, Peerless, Weil-McLain et al). That 18-inch horizontal run probably worked best to dry the steam and/or reduce strain on the boiler sections when they tested the drop-header configuration.

I'd go with Burnham's recommendations. You really can't go wrong if you do. And post some pics when you're done!

Boilerpro_3

That's what I was thinking

The longer the lever, the less strain on the boiler, because the piping is leveraged to move easier.
That's why I keep my offset a little longer from my supply tappings to my header.
I've got another steamer going in in a week or so.... Blake's from Indiana. I've done more steamers this past year than hot water.

Boilerpro

The Wire Nut

Burnham drop header...

I just finished (literally) building this header and wet return to replace the unenlightened install on my Burnham V83. Thanks to Dan and the info I picked up on the Wall, I can truly say that the drop header works.

When I fired it up I think the old mains felt steam for the first time in many, many years. Last winter (when we bought the house) we burned almost 2000 gallons of oil being here just on weekends. It would take hours for the radiators to get warm, and only a few sections on most would get hot. Some radiators never got warm. Tonight they did...

Attached are photos of my header and the equalizer and Hartford loop. Although I didn't follow Burnham's diagram (no way I could have fit those 18" legs) I think you'll have no trouble with the drop header... If you need specifics, I can provide you with the piping sizes I used...

tommyoil

Few questions

First of all it looks better than it was HOWEVER isn't it preferred to have the steam moving in the same direction as the equalizer instead of splitting the header in two directions? One direction toward the supplies and one toward the equalizer? Isn't the steam fighting to go in two directions now? Also, Are the flanges supposed to be on the horizontal piping and not the vertical piping? I was always taught that flanges go on the horizontal piping. Is there any truth to this? Ball valves on steam???? Aren't they in some way restrictive to steam flow?( even if they are full port) Are they rated for such? Does anyone make a decent steam ball valve that will be functional past the first heating season? Just a couple of questions.

Ken_8

Frank (Steamhead),

You wrote, "and/or reduce strain on the boiler sections when they tested the drop-header configuration."

This assertion suggests NOT using a drop header DOES place strain on the boiler sections/block.

Can you site ANY case where a boiler with merely a "swing arm" of two (or more) riser arrangement compromised boiler sectional integrity?

Second, by what means do dropped header piping development REDUCE installation time? Or, for that matter, use less pipe or fittings than the commonly accepted swing arm riser schematic drawings 100% of all manufacturer's have adopted for the past 100 years?

I have no empirical data to support or deny the benefits (or waste of time, as well as added materials required to do drop headers on residential steamers). I have a bunch of anectdotal "evidence" that has no place in critical thinking and analysis.

I suggest using a single 3" riser on all steam boilers under 700 S/F. of EDR is "oversized" by most manufacturer's specs. and will do much more to reduce water carry and reduce installation time than any reduced size twin risers configured with a drop header!

Drop headers are the solution to unacceptable vertical limits in regard to NOWL to-(main)-header dimensions. When dealing with 50 HP (and up) installs with pipe sizes over 4", drop headers also take a place of being superior to standard swing-arm patterns - but not because of allegations of "stress" or drier steam, but rather the riser to pipe diameter ratios that must be met, to assure dry steam.

No one has offerred any serious evidence that drop headers (as they are being bantied about here on small steam systems, as posessing some "miracle cure" for some unknown and undocumented "problem" that has been more based upon some unfounded notion of "being cool" or may help a problem that never existed) actually "fix" anything!

I'm not saying it doesn't "do" whatever you're suggesting it does. I merely suggest the absence of any factual/scientific data to support the notion that a dropped header is somehow "superior" to the installation schematic diagrams offerred by virtually every boiler manufacturer on the planet as being adequate, embrace an efficienct use of both installation time and pipe/ftgs. needed - and that all the oohs and ahhs we read are based more on the fact that a dropped header does look very cool - and may in fact have some extremely marginal advantage over a common swing arm install - but in reality, is merely one of many ways deployed to make our installations unique - rather than common.



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Mad Dog

Me too, Ken

I use drop headers to cure oversized boilers, and just generally for the driest steam money can buy. Mad Dog

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Steamhead

My exact quote was

"probably worked best to dry the steam and/or reduce strain on the boiler sections when they tested the drop-header configuration."

You missed "probably", which means they had their reasons for specifying that 18-inches, due to extensive testing. Without talking to someone at Burnham, we can't be 100% sure of their reasoning, but we can make our educated guesses which is what I did.

I have found from experience that when a boiler has two or more risers to the header, a drop header is much, much easier to install than a standard header. That extra swing joint at the header is the key. This more than offsets the cost of two or more street elbows. On a boiler with only one riser to the header, we can still use a drop header for increased riser height if needed.

And yes, they do look very cool!

Steamhead

Alex, I have to agree with Tommy

Though it certainly is better than it was, in its current configuration it won't separate water from steam properly. You want the steam to enter the header on one side of the steam main takeoffs, and to dispose of the water thru the equalizer on the other side of the steam mains. That way, when the steam makes that sharp turn into the steam mains from the header, the water will be thrown out of the steam in the direction of the equalizer.

I've attached a shot of a header we did on a Burnham V-34. This one is not dropped (but we did oversize it). Can you see how the steam and water flow thru this header?

That said, the vastly increased riser height from the boiler to the horizontals leading to your drop header is probably separating the water just fine. If the system heats up properly as you say, and doesn't bang, you're probably OK.

I realize it took a bit of courage to post your work on here for the first time, so I don't want to sound like I'm busting your chops. These are things to keep in mind for the next time.

You might also want to check your main vents to see if they're the right size, if you haven't already.

The Wire Nut

Drop header...

Well, I certainly no expert, just a serious student! From what I understand, the steam is not really "splitting" as there is no real steam flow through the equalizer, but more of a static pressure to equalize the pressure difference between the return and the feed.

What does flow through there is condensate, mostly the stuff dragged up by the violence of the steam's movement from the boiler. This is why you need long risers and why a drop header helps. If you ever have a chance to see the Weil-McLain demonstration boiler with the glass piping, do so. You'll be amazed at how much water is pulled up by the steam, and how much flows back down the equalizer.

It's important to have the header slope back towards the return line, so that gravity does it's thing for the condensate.

You would have problems, if, for example, you had a tee between the two risers (a "bull-headed tee") as one of the take-offs. This would cause the steam to flow in two directions and create internal turbulance that would impeed flow.

As for the flanges, I have no idea. Not being a plumber or pipe-fitter, I put them where I thought they would work best. Having had to break several of the old unions (using my rail-thin, all muscle neighbor Bill, a 36" old-fashioned "Monkey" wrench and a 4' piece of 2" pipe as a handle), I wanted to have a joint that could be split easily if and when the bolier needs to be replaced. I suppose I should have used them at all the places I used unions, but, as it was, the budget was strained the moment I had to pay for the couple of lengths of black pipe I needed to create the header and wet-return...

They are full-port ball valves. I have seen them on a number of installations and on some of the photos I have seen posted on The Wall. I don't see a problem with them as a restriction, they certainly seem to have more throat then the street-ells I used. From what I can tell, the seals are teflon or some other high-temp material. In any case they passed the maiden firing with ease, and opened and closed at pressure with no problem.

The Wire Nut

Take-offs,

Steamhead,

Nothing is criticism if you can learn from it, and I appreciate that you took the time to post a reply. I had the pleasure of meeting you at Wetstock this Spring and have read your posts over the past year, so I know what you say is for our edification and not criticism.

Given the placement of the boiler and the existing risers, It would have been a lot more pipe-fitting and a hell of a strain on the back to get the take-offs on the other side of the risers. That excuse being given, I suppose I could have moved the boiler or changed its orientation, but given the space constraints I left it as put.

I am curious, though, when the steam makes the turn in my header and the water drops off, won't gravity pull it down the header to the equalizer?

I suppose I could swap the equalizer piping around and have it flow back behind the boiler and into the return, I would have to adjust the slope too, but that's a matter of swapping some nipples...

So far there has been no hammering from the mains or risers. Granted half the radiators are disconnected for painting, so I can't tell for sure. I did get hammering in the wet-return when I shut the valve to my long main and left the short main (1 connected radiator, 2 removed for painting), but I figured that with all the excess heat, my return turned into a large water filled radiator!

My vents are way too small, they are 3/4 Maid-O-Mist main vents. None of the supply houses here carry Hoffman or Gorton. I will pick up the appropriate vents at my supply house in NYC.

On my test firing last night, once the steam came up, the mains did get hot fairly quickly, so I imagine the vents are doing the best they can.

Thanks for taking the time to reply and I am open to any other critiques or suggestions... It's how you learn...

Steamhead

Answers

"I am curious, though, when the steam makes the turn in my header and the water drops off, won't gravity pull it down the header to the equalizer?"

It might, but it would have to flow in the opposite direction the steam is moving. This is much more difficult and would usually require larger pipes so the steam and water can keep out of each other's way. Compare the steam-carrying capacities of a parallel-flow and counter-flow main and you'll get the picture.

"I suppose I could swap the equalizer piping around and have it flow back behind the boiler and into the return, I would have to adjust the slope too, but that's a matter of swapping some nipples..."

That's exactly what I would do!

"My vents are way too small, they are 3/4 Maid-O-Mist main vents. None of the supply houses here carry Hoffman or Gorton. I will pick up the appropriate vents at my supply house in NYC."

How long are your steam mains, and what pipe size are they?

The Wire Nut

Vents...

Mains are 2". The "short" one is about 25' and feeds 3 radiators. The "real" end of this main is under an inaccessable crawlspace (well, inaccessable to me as there are limits of what I'll do for steam...). That pips is 2" and of unknown pitch. I treat is as a take-off and count the Tee where it connects as the end of main. That take off adds about 20' and feeds 2 radiators in the kitchen.

The "long" main wraps around 3 sides of the house and is about 75' long. It's 2" for its entire length. It feeds 6 radiators and about 15' of cast-iron baseboard (through 3/4" copper!). I've attached a diagram I did prior to this work. The current mains layout is the same as the diagram...

The Wire Nut

Vents...

Mains are 2". The "short" one is about 25' and feeds 3 radiators. The "real" end of this main is under an inaccessable crawlspace (well, inaccessable to me as there are limits of what I'll do for steam...). That pips is 2" and of unknown pitch. I treat is as a take-off and count the Tee where it connects as the end of main. That take off adds about 20' and feeds 2 radiators in the kitchen.

The "long" main wraps around 3 sides of the house and is about 75' long. It's 2" for its entire length. It feeds 6 radiators and about 15' of cast-iron baseboard (through 3/4" copper!). I've attached a diagram I did prior to this work. The current mains layout is the same as the diagram except the long main vents at the bottom left near where it says "T 2nd floor bathroom." The return is 1 1/4 wet.

(The old return was a mish-mosh left over from an older, taller boiler, and ran at mid-height along the wall then dropped down under the cellar steps and in to the return, sans equalizer of loop. The short main connected to this with a water-seal loop...) I have lots of photos if you want, perhaps bettor off-line?

Steamhead

Try

a Gorton #2 on the long main, and one or two of your Maid-o-Mist vents on the short one. That should balance your mains nicely.

On the short run, bite the bullet and put the vent(s) in the crawlspace. This will balance the entire network of mains.

Unknown

Ken , there might be a long wait

for factual / scientific data that supports or denies that a dropped header configuration is a superior way to pipe a steam header .

My info might be anecdotal , but for the past few years we have been dropping our headers on every steam install , probably close to 100 , and the callbacks for surging and banging pipes have been cut down dramatically . It could be from a number of things - maybe we skim the boiler and clean the returns longer after install . Maybe the houses we work in are all piped and pitched better than past jobs . Maybe we got lucky and there was a main vent on each takeoff and it was sized right . Or it could be that the extra drop into the boiler main does separate the steam from the water carried up better than no drop at all .

This might be a longshot in a dwindling steam market , but how about we lobby a boiler manufacturer , training campus , anyone in the trade , to test 2 of the same steam boilers , one with a drop header and one without , and actually see if theres a difference in performance .

Personally , the main reason I drop the header is to save time . After many , many times of trying to match that last nipple up between the 2 boiler risers - threading one in , taking it out , threading another size in - just to mate the union up exact - dropping the header assures you the union will seat right no matter how far off the last nipple is .

Unknown

Jon , I think

their piping schematic is a best case scenerio , if you actually have all that room to work in . We pipe the headers high and tight , space is a premium even with steam systems in our area . My intuition tells me that the dropped header we use , as well as a full size ell and pipe for the equalizer , has been helping dry the steam going out to the system .

Ken_8

Once again...

All anectdotal evidence.

What ever happened to critical thinking? Stories and guesswork are not hard science nor factual.

Ron, FYI I have never installed a boiler without TSP'ing it AND skimming it in 10+ years and despite never having used a drop header deisgn, have no, zero, nada experiences with water hammer!

Water hammer is NOT caused by "wet" steam (define wet, medium wet, somewhat wet, almost dry, very dry, etc. steam) it is caused by puddles in pipes that implode upon the presence of live steam!

I respectfully submit that the use of dropped headers is an excellent cure to a problem a properly piped boiler would never have anyhow.



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Unknown

If you have never had an

experience with water hammer in he last 10+ years , then the heating systems in New Jersey must be in original condition , every pipe sized and pitched right . Or you just don't get on enough steamers ? Or is it your opinion that a good cleaning and skimming cures all the ills of a problem steam system ? In any event , I am envious . A good majority here have add ons piped in wrong , settling houses and pipes with bellys that are uninsulated , or incorrect sizes . Before we dropped our headers , we piped our boiler mains one size higher than specs . Since we have been dropping our headers , the callback ratio has dropped significantly . Very few calls for spitting vents , surging boiler water , and banging pipes - which can be caused by carryover water with steam when they bang into each other at a tight turn . Guesswork , stories , lack of critical thinking - whatever you want to call it , I really don't need a host of engineers in lab coats working on steamers in a lab to tell me the cost of 2 extra street ells saves time , gives the boiler more " swing " to relieve stress between 2 boiler risers , and in my educated opinion , lessens water carryover to the mains than a traditional header ( although it would be nice to have backup info from the lab coats for my opinion ) . If you have ever seen the Weil Mclain glass pipe steam boiler , you know how much water can be thrown up into a header .

Like you said , all this info I have collected in my hundreds of steam installs might be considered anecdotal . The drop in the header might not " dry " the steam as much as we think it does ( sorry , I don't have the exact measurements for what constitutes dry steam to wet ) , it ain't the cure-all of a sick system , but it certainly doesn't hurt .

Unknown

The dropped header

configuration that we show in our drawings utilizing 13"(+/-) swing joints (not 18") on the V8 is simply to get the horizontal piping across the top of the jacket before dropping and to try and align it with the right rear return. This way the boiler can be properly cleaned and serviced and the flue pipe should be out of the way of the piping. There are many that prefer dropped headers because they say they produce drier steam. I agree with this also. But a boiler that is piped correctly without a dropped header can also produce dry steam to the system. Many people I get to speak to in my seminars have found it much easier to maintain proper pitch on the header to the equalizer with dropped headers simply because of the increased number of elbows and nipples. I do agree that they perform well in applications where it is difficult to maintain a good rise distance from the header to the system mains while still maintaining a good rise from the water level to the header. This was the primary purpose of utilizing this type of piping.

The 18" swing joints we normally call for in the piping diagrams provide for a longer pivot arm in the case of much larger boilers with many risers. To answer your question Ken, we have seen steam boilers (commercial) with absolutely no swing arms and multiple risers connecting straight up into header tees that suffered the consequences of expansion. Some were lucky enough to break only a draw rod. Others encountered broken bosses that the draw rods go through. In both events, the boilers had to be taken apart and reassembled.

I do have a comment about the valve at the end of the header though. Although this point is a very effective point for skimming, I would strongly advise putting a plug in that valve. Curious people and kids happen and I'd hate to see anyone get a face full of steam. Hope this helps.

Glenn Stanton

Burnham Hydronics

Jim Roche

Drop Header

The drop header in residential steam is recommended
primarily to solve a frequently encountered installation
problem.
The vertical height of steam boiler supply risers are critical. The industry is suggesting a rise of 24" from
the boiler waterline. Under normal operating conditions
that distance is sufficient.
When water begins to boil(latent energy violently
separating water molecules from one another)across the
width and length of the boiler with only one or two
relatively small openings. The "expanded water" begins
to move rapidly. This velocity flow creates a negative
pressure at the openings and splashing water will be
sucked up with the steam. Under normal operating conditions the industry's height recommendations will prevent most of the water from reaching the steam header.
Many basements have low system piping. A drop header will permit an installer to abide by the industry
recommendations and yet be able to lower the boiler steam
header to make a convenient connection to the system.
Besides correcting an installation problem, many
installers find that a drop header will develop dryer steam:the essence of good steam heat.

The Wire Nut

Vents...

I'm doing some computer work for my NYC supply house in exchange for goods, so I'll get a couple of Gortons to replace the M-O-M vents.

I was thinking that I would remove the radiator valve on the radiator at the far end of the kitchen. It's still 2" and I was going to pull off the leaking angle valve, put on a Tee, and put a new valve on the bull. From the the top of the Tee I'll bush down to 3/4, put on a 15" nipple and install a nice size vent... How does that sound?

Steamhead

That'll work!

I doubt you'd need the 15" nipple if you're at the top of the riser, but it can't hurt.

The Maid-o-Mist #1, which I think you now have, is similar to the Gorton #1. Four of these equal one Gorton #2.

Have you verified that there is in fact no vent in the crawlspace, which might spring a leak later?

The Wire Nut

Creepy-crawlers...

There is a small access hole, filled with fiberglass batts and dead things. I peeked in once last winter, but didn't really see much. I'm not anxious to open it up again... However, I will hopefully have the kitchen floor removed so I can seal the crawlspace with plastic. At that time I can check the piping, and replace the domestic plumbing and electric too...

I was thinking of putting radiant in the kitchen while I have it open...but that's another story...

The Wire Nut

Made o vents...

From what I've read on several posts here on The Wall, the M-O-M are not quite the quality of the Gorton. Should I use the Gorton #2 on both mains, if I put the vent by the radiator?

don_52

Contempt Prior to Investigation

Hello (W)all,

Once again... All anecdotal evidence.

What ever happened to critical thinking?

Stories and guesswork are not hard science nor factual.

Quite a controversy! More than ancedotal evidence
exists as to why dropped headers;

a.) improve steam quality.

and

b.) are easier to install.

Addressing a. first,

The simplest is the steam velocity equation ( as a "simple" working proof}
and the also controversial "15 inch" dimension
between the last takoff and the riser.

Put together some working examples down on paper and it
becomes a little more clear without throwing in all of
the "chalkdust" calculations that are required for an
"empirical proof". The effect is similar, although not
exact, to what happens in "knockout drums".
Granted there is no "proof on this page, we aren't
considering the thermodynamics, 3k eq. length method,
reynolds number, Fanning, Darcy or Moody friction factors,
transition from full turbulent to laminar flow , the decaying trajectory of suspened particles of liquid in vapor and of course the "residence time" provided by the infamous "15 inch" dimension and it's effects on saturated, dry or superheated steam quality, that is all contained
in "engineering text", please consult "cheresources"
on the web or a good Mcgraw-Hill pipng and mechanical
text, its all there, if it wasn't none of us would be "here".

secondly b.

Not everyone has the luxury, time or money to completly
gut the basement and start over.
In the case of our house; the first boiler was a round
"ground coupled" coal burner, then oil, then gas, needless to sayafter 98 years the near boiler area was less than ideal.
There are plenty of folks who have installed same for
the reasons stated and "as a practical matter" have found
them to be beneficial in retrofit installs regardless of any of the primary, secondary and tertiary effects of installing a dropped header.
While not an "axiomatic or empirical proof" I trust the
observations of the craftsmen who having donesame in the "working laborotory" of the real world as a "practical working solution to problem".
This is after all what "journeymen fitters" do every day,
for which the writer is grateful for.

We'll discuss valves next time.

good night

"In theory, "practice and theory are equal", except in
practice.

don_52

Contempt Prior to Investigation

Hello (W)all,

Once again... All anecdotal evidence.

What ever happened to critical thinking?

Stories and guesswork are not hard science nor factual.

Quite a controversy! More than ancedotal evidence
exists as to why dropped headers;

a.) improve steam quality.

and

b.) are easier to install.

Addressing a. first,

The simplest is the steam velocity equation ( as a "simple" working proof}
and the also controversial "15 inch" dimension
between the last takoff and the riser.

Put together some working examples down on paper and it
becomes a little more clear without throwing in all of
the "chalkdust" calculations that are required for an
"empirical proof". The effect is similar, although not
exact, to what happens in "knockout drums".
Granted there is no "proof on this page, we aren't
considering the thermodynamics, 3k eq. length method,
reynolds number, Fanning, Darcy or Moody friction factors,
transition from full turbulent to laminar flow , the decaying trajectory of suspened particles of liquid in vapor and of course the "residence time" provided by the infamous "15 inch" dimension and it's effects on saturated, dry or superheated steam quality, that is all contained
in "engineering text", please consult "cheresources"
on the web or a good Mcgraw-Hill pipng and mechanical
text, its all there, if it wasn't none of us would be "here".

secondly b.

Not everyone has the luxury, time or money to completly
gut the basement and start over.
In the case of our house; the first boiler was a round
"ground coupled" coal burner, then oil, then gas, needless to say after 98 years the near boiler area was less than ideal.
There are plenty of folks who have installed same for
the reasons stated and "as a practical matter" have found
them to be beneficial in retrofit installs regardless of any of the primary, secondary and tertiary effects of installing a dropped header.
While not an "axiomatic or empirical proof" I trust the
observations of the craftsmen who having done same in the "working laborotory" of the real world as a "practical working solution to a problem".
This is after all what "journeymen fitters" do every day,
for which the writer is grateful.

Having said all that; given good to ideal circumstances a
dropped header could be considered a "technical conceit"
that is however contrary to the scope of what others have stated as their justification for installing same.

We'll discuss valves next time.

good night

In theory, "practice and theory are equal", except in
practice.

Robert O'Connor_7

don

Could you please say that a little slower..Robert O'Connor/NJ

don_52

once more...with feeling

okie doak,

bubbles please, a one anna two...

Been talking with a guy from the wall about
putting all the techno-babble into a "pocket
guide" type format.
Sitting and looking at all the math as to the
how and why is even worse, hard on the eyes.

cheers

don_52

once more...with feeling

okie doak,

bubbles please, a one anna two...

Been talking with a guy from the wall about
putting all the techno-babble into a "pocket
guide" type format.
Sitting and looking at all the math as to the
how and why is even worse, hard on the eyes.

cheers

Ken_8

Ron,

> experience with water hammer in he last 10+ years

> , then the heating systems in New Jersey must be

> in original condition , every pipe sized and

> pitched right . Or you just don't get on enough

> steamers ? Or is it your opinion that a good

> cleaning and skimming cures all the ills of a

> problem steam system ? In any event , I am

> envious . A good majority here have add ons piped

> in wrong , settling houses and pipes with bellys

> that are uninsulated , or incorrect sizes .

> Before we dropped our headers , we piped our

> boiler mains one size higher than specs . Since

> we have been dropping our headers , the callback

> ratio has dropped significantly . Very few calls

> for spitting vents , surging boiler water , and

> banging pipes - which can be caused by carryover

> water with steam when they bang into each other

> at a tight turn . Guesswork , stories , lack of

> critical thinking - whatever you want to call it

> , I really don't need a host of engineers in lab

> coats working on steamers in a lab to tell me the

> cost of 2 extra street ells saves time , gives

> the boiler more " swing " to relieve stress

> between 2 boiler risers , and in my educated

> opinion , lessens water carryover to the mains

> than a traditional header ( although it would be

> nice to have backup info from the lab coats for

> my opinion ) . If you have ever seen the Weil

> Mclain glass pipe steam boiler , you know how

> much water can be thrown up into a header .

> Like you said , all this info I have collected in

> my hundreds of steam installs might be considered

> anecdotal . The drop in the header might not "

> dry " the steam as much as we think it does (

> sorry , I don't have the exact measurements for

> what constitutes dry steam to wet ) , it ain't

> the cure-all of a sick system , but it certainly

> doesn't hurt .





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Ken_8

Ron,

As usual, your commentary is thoughtful, considerate and respected.

You wrote, "If you have never had an experience with water hammer in he last 10+ years , then the heating systems in New Jersey must be in original condition , every pipe sized and pitched right."

I didn't mean to mis-lead you. With the exception of the Mighty Passaic River, NJ and L.I. are extremely alike. But badly pitched mains and floor joist hangers that have fallen from "true," and puddles of condensate in the mains and bad vents are not "solved" by dropped headers. OR are you suggesting dropped headers can overcome bad pitch downstream? If so I'll begin using dropped headers yesterday!

Then you go on to ask, "Or you just don't get on enough steamers"? To be honest, we do more steam than hot water. About 250 in the past 10 years. Of those however, 10% are well over 5,000 S.F. of EDR (big stuff).

Then you ask, "Or is it your opinion that a good cleaning and skimming cures all the ills of a problem steam system"? No, not all ills. But damn near! It will not cure improperly located main vents. It will not cure bad rad vents, it will not overcome a pressuretrol setting of anything over 2#, Nor will it fix missing insulation on the mains.

But it will cure priming and surging every time. It will prolong rust inhibition by leaving the water pH above 7.0. It will prevent rapid return of rust formation in the near boiler piping and any piping below the NOWL.

You also wrote, "If you have ever seen the Weil Mclain glass pipe steam boiler , you know how much water can be thrown up into a header."

Ron, I was the factory authorized start-up and trouble-shooting service man for Weil McLin in north Jersey for many years - and still do that kind of work for them. I helped them find the designs and materials to make the "glass" near boiler demonstration piping. Since you saw it as well, do you really think the tempest in a tea pot we see inside those pipes really is eliminated by your beloved dropped header?

The single most important piping consideration with regard to the near boiler pipes is NOT a dropped header. It is the diameter of the riser(s)! Water carry is inevitable. Minimizing it can occur if we allow the velocity of the existing wet steam to be slowed. The more we slow the velocity down, the more tendency for water droplets to drop away from the gas we call steam.

The fact that most boilers do not have adequately sized riser tappings to make truly "dry" steam - forces us to overcome that shortcoming by the use of multiple risers, or perhaps even a dropped header. But simpler and better yet, if a boiler's minimum stated riser dia. for the EDR rating required is 2", and the outlet riser dia. is 3" (as in W/M's EG series)- use a 3" riser! The steam velocity will be so slowed, water carry will be reduced and the driest steam possible can be the result.

Dropped headers can achieve two things:

1) Overcome a physical limitation (like a low ceiling - or too "tall" boiler) and permit the 24" NOWL to steam-main magic number to still be developed or;

2) Allow us to overcome the inherent shortcomings of small riser tappings of many boiler blocks - and the excessive velocities that undersizing will induce - and the resulting water carry (a/k/a "wet steam") that must occur.

If the recommended minimum riser size is for two, 2" risers and the boiler 3" tappings, by using the full size outlets, we reduce velocity by something on the order of 250%! If we used 2" and installed a dropped header, we would reduce riser velocity by zero.

It's all about riser velocity. Dropped headers allow us to artrificially create a second steam chest. The advantage we presume is that everytime we allow the "water-carry" another chance to eliminate those droplets - resulting in drier steam (via the equalizer "dump" at the end). If we were able (and with some boilers we are) to increase the riser diameter one or more pipe size diameters from the minimum, the need for or desired effect of a dropped header becomes moot.

We must also be aware of the minimal but ever present centrifigal forces of water exctraction that occurs with every change in direction. A dropped header would necessarily create a few more changes in direction before leaving the header - and perhaps does reduce some water-carry because of the extra ells. But without a pipe diameter change, water laden steam will not benfit from reduced velocity, and water will be carried at virtually the same rate as any minimally sized riser/header scheme without the dropped header.

One of my ASHRAE books does show a table of steam velocities at various pipe diameters. Because of the laws of math regarding circles (pipe diameters) a doubling of pipe diameters, will provide 4 times the area (and even less than one-fourth the velocity) than the smaller pipe.

Wait a minute. Are we in complete agreement that the velocity of the steam out of the riser is what causes water carry? Because if we don't agree to that fundamental premise, you'll continue to use dropped headers - without knowing why they can work - but are completely unnecessary in most steamers under ~500 S.F. unless of course, the outlet tapping(s) are only inch-and-a-half (;-o)




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Ken_8

I note with great joy,

the schematic attached to your post implies risers of a certain diameter and a dropped header OF LARGER DIAMETER!

This fact seems to have been completely missed by those who would tell us the "wonders and vast improvement" of deploying the dropped header near boiler setup.

Like I wrote in another post, the velocity of the wet steam is critical to its shedding that "wetness"!

By increasing the dropped header pipe size as depicted in YOUR schematic, we accomplish that very goal. That alone is the true benefit of a dropped header.

However, if the 24" minimum suggested height IS well within reach, simply piping riser(s) into a non-dropped header - and increasing the header diameter would achieve the same end result - REDUCING STEAM VEOLOCITY TO ALLOW WATER TO DROP OUT OF THE STEAM!

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tommyoil

Wheres the benefit

Can someone please explain to me just exactly where I would notice the benefit(performance wise) of a unit utilizing a dropped header( on a residential unit) as opposed to a unit piped in a standard piping arrangement? If I pipe all of the near boiler according to a manufacturer spec sheet, just where would I look to find the difference in performance?Systematically? Does the steam get to the rads faster? Does it take less fuel to operate? Wouldn't I be more likely to have a problem with an improperly piped dropped header(as I have seen here) than a properly piped standard set up? I understand that dry steam is the ultimate goal here. Will the steam be that much "drier" ? (And yes, I have seen the Weil/Mc glass piped boiler) I dont want my justification for employing a dropped header to be just so I can line up my equalizer union.I can use my tape measure for that.While I submit that I have never done a dropped header in a residential application, I can definately see the reasoning if I were having water line to supply piping issues. The next job I come across with that issue will be addressed with a dropped header. But that would be about it. If I do my homework when I get to the job and check the whole system for potential pitch problems, Dim. A throughout, venting, ect, before the new boiler goes in, perfomance wise, where will the difference be? That is all I'd like to know. I dont feel as though I have shortchanged my customer for NOT piping in a D.H. Further it does not seem easier to pipe in. There appears to be more material/fittings ect... It doesn't seem harder or more time consuming, but it doesnt seem easier either. It just seems like a big Broadway production with a story line that goes nowhere. Also, would someone please comment on flange orientation. Is there a preference? Should flanges be on the vertical or horizontal runs. Is there a difference performance wise? On welded headers( when we had to) the flanges have been on the vertical rise from the boiler. But on threaded, we install them on the horizontal. Is there a difference?

Ken_8

No need.

It's anectdotal "proof" of even more anectodal "evidence."

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Mad Dog

Perhaps, Ken...

wish I had the time and $$ to set up a laboratory. I can tell you this, on the average residential boiler it may be overkill. However, I have found - through much trial and error - that drop headers make the difference for problematic systems, no question about it. Ken, as you know I am a big fan of no-holds barred fighting. I love seeing what really works in a fight and what doesn't. I have had many brawls with THE STEAM....getting beatings for many years until I learned what really works in the steam fight. Drop headers are an important part of my fight plan going in to a problem job. Do I use them on every job? No but quite often, and as Ron and the others say, it makes lining up the take-offs easy. Mad Dog

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Ken_8

Ron, had you increased the

pipe diameter of the horizontal dropped header, there would be no argument about its absolute superiority!

But you didn't - and therefore its superiority is merely perceived - not substantive.

Do you recall Dan's overhead of the physics of tees? The issues of whatever goes into one tee is always equal to what ever comes out? Friction losses aside...

If the velocity of the two risers is say 20 C.F./minute a piece. When they are re-connected at the first tee of the dropped header (and down stream a few inches to the first system riser), the velocity will be 40 C.F./minute! This exacerbates the water throw problem at that point - in no way reducing it!

Assuming both system risers are equal in load, the first tee takeoff will have steam entering the tee at 40 C.F./minute and slowing to 20 as it exists the "bull"/riser and the "run" continuation to the second system riser.

The essence of my post is that the dropped-header as you all pictured (with the exception of the Burnham schematic - which no one apparently understands why it is shown, Glenn clearly states it is to overcome dimensional problems not reduce water carry per se) does not reduce water carry! If the dropped header is LARGER in diameter than the combined riser area - IT WILL HAVE AN EXTREMELY POSITIVE IMPACT OF REDUCING WATER CARRY; but so would a "conventional" header, if area is increased!

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Ken_8

I agree with Jim's

explaination completely. And if you know who Jim is, you would as well.

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Ken_8

I agree!

The way in which the dropped-header advocates pipe it, makes no sense and there is no need nor advantage in doing it. If the extra elbow has any impact on steam quality - it is so minimal as to be insignificant.

Does it look cool? To a few of us, yes. But that begs the bigger question; Does cool = better?

There are legal considerations here as well.

Manufacturer's will void warranties because of failure to follow installation instructions. Other than Burnham (and for reasons that have nothing to do with cool - but rather height limitations being overcome) I know of no manufacturer who advocates under 500 S.F. EDR steamers to be piped using dropped headers!

Dropped header piping is as common as having no Hartford loop! It ain't in the schematics - therefore it is NOT approved by the manufacturers!

Do you really thing the typical plumbing inspector will look at the manufactuer's schematic, see your dropped header - and think, "Wow, this is a work of art"? Most would look at the dropped heaer and refer to the code that says, "Near boiler piping shall conform to the manufacturer's recommendations."

Can you spell "F*A*I*L*E*D" inspection?

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Steamhead

You need more venting capacity on the long main

But you could put a Gorton #2 on the crawlspace/kitchen end of the short one, and a Gorton #2 plus your two Maid-o-Mists on the long one.

The idea is to make sure steam reaches the ends of both mains at about the same time, and not much more than a minute later than the point at which the boiler starts producing steam.