Drop header question.

Steamhead

Tommy, the installation advantage

of a dropped header is the extra swing joints you get from the elbows that turn down into the header. When you're trying to line everything up and one of the joints makes up a little long or short, a little adjustment at the swing joint brings everything together nicely, and with almost no strain.

Obviously this only comes into play on a boiler that needs two or more risers to the header. But how many steam boilers are there that only need one riser? The vast majority I've seen need two or more.

Given the choice, I'll spring for a couple of street ells rather than get into a fight with the pipes while trying to put the header together.

tommyoil

still need a reason

Indeed, the majority of steam jobs DO have two or more supplies.To say that I havent had trouble at one time or another making up or lining up fittings would not be true. I have. Just not lately. Swing is king. I have no problems with lining up piping/fittings on anything where a dropped header would have helped me. I feel that if the boiler is set level, square, and the appropriate use of proper fittings(swing joints)and tools(level and a tape measure) are on the mark, lining up anything shouldnt be a problem. I dont feel the need to drop a header just to get my fittings to line up. If I heard an arguement for increased performance( proven not speculated) I would start today dropping every steam header I ever do. I just dont see it on residential. Why dont manufacturers suggest it as an option in their schematics?And something I didnt consider here, and Ken has touched on it. Although the D.H. arrangement may/may not noticeably increase performance, what will it do for me liability or inspection wise. If God forbid something should happen, will the manufacturer come in and say they approve or will they cut me loose as a renegade using unapproved piping methods. And who will re-pipe when and if I fail inspection for failing to comply w/ manufacturer recommendations? Certainly dont want to be left holding THAT bag. My question still remains, where in the system will I notice the difference in performance if using one method as opposed to the other. Will I ever? Will the homeowner? Will the fuel bills be lessened? Will the pipe last longer? Boiler last longer? Roof last longer? Dog need less grooming? I need something, ANYTHING, besides getting my fittings to line up as a reason to employ this method on a residential steam unit. I am not against this method and actually it does add a unique look.But I'm not "diving in" until I see the water is deep enough.

Boilerpro_3

Say, Is that Don from Chicago?

If it is, I'm especially glad you jumped in! If not, Im still glad to have you here!

Dug out those old steam engineering texts yet.

Ken makes me a good point, show me the proof under lab type conditions.

Boilerpro

Unknown

I have to say Ken

I do not know where you find the time to write these succinct responses . It takes me a good 20 minutes to write a complete paragraph and make it half way literate .

In no way would I suggest a dropped header is the cure to bad piping downstream . What I would say is that a dropped header can dry out the steam just enough to overcome some other problems downstream - problems that might rear up with a normally piped boiler header . I won't say it cures all the ills - we had a problem job this past year , 2 risers , dropped header , boiler main oversized , new main and rad vents , everything insulated - cleaned and skimmed for over 5 hours myself , and still had banging , spitting vents and uneven rad heating . We wound up replacing about 100 feet of 1 inch black returns and repiped an add on header to an extension . As far a I know , except for a commercial size steamer with troubles , this was the only steam boiler that kicked back to us over the winter , maybe 30-40 in total .

I totally agree with you , the bigger the supply tapping out of the header , the slower the velocity , the greater a chance for no carryover of water into the system piping . But as you know , most residential steam boilers , with Weil and a few others as the exception , have one , possibly 2 , 2 inch supply tappings . With water carryover into the boiler main being inevitable , would you think there would be a significant difference if we increase the supply size right out of the boiler ? Or would having a larger than recommended boiler main do the same at separating the steam from water ?

Like Dan says , I'm trying to think like steam and water . If it's mixed together going up the boiler supply and then has a drop into the header , I would think the carryover water would drop down to the bottom of the oversized main and separate easier than hitting that main directly on a horizontal . But without actually seeing what is happening in the piping , it's just conjecture .

Unknown

Kenny , put on your spectacles

the horizontal main is increased , to 2 1/2 or 3 inch , I forget which size . Or do you mean I should have increased it more ? Always a good idea , but gets cost prohibitive .

You say the 2 boiler risers could increase water throw problems at the 1st tee of the dropped header . Wouldn't it also do the same for a non - dropped header ? Whats the difference ?

But wouldn't using 2 boiler risers , instead of the one that Burnham recommends as a minimum , actually decrease the velocity of flow into the main ? Sort of like using 1 oversized riser ? Or does it just decrease exit velocity from the boiler ?

Robert O'Connor_7

Jim...

I think you nailed it...Robert O'Connor/NJ

Ken_8

Got me!

Now that you point it out, I can barely see a one pipe-size increase at the bottom elbow - but it sure looks like its bigger. However, few if any of the OTHER pictures posted are!

And that's a complete waste of time, IMHO.

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Steamhead

If you're still nervous

check with the rep for the boilers you use. I'm sure you'll get their blessing.

BTW- which boilers do you all usually use on steam jobs? With us it's mostly Columbia, but we use Burnham too when the owner asks for it. Never had a problem with either.

Ken_8

Come on Frank,

Most of the reps we know wouldn't know a "dropped-header" from a sweet potato.

Find one who actually understands the concept, and who would sign a waiver, over-ruling the manufacturer's installation manual and schematics and I'll listen.

I'm just not holding my breath.

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Steamhead

How about

showing this thread to your reps (Weil-McLain, if memory serves) and see what they have to say?

Ken_8

That could work...

But I doubt it.

Remember, our work is inspected by guys who failed as plumbers, knew someone in politically high places, took a 2/3 of a year course and are now plumbing inspectors.

All he knows is what the installation manual shows. He has no interest as to whether I piped it correctly, skimmed it, or put any vents in. All he knows is a picture and my work.

If he saw a letter from W/M sanctioning a dropped header, he wouldn't understand it and would fail the job - merely because it does not look like the picture.

With the single exception of Bob O'Connor, I can assure you they would not have a clue. Mosdt of the tricks our local W/M brain trust knows - are from stuff we shared along the way. They change reps about every three years.

Having said that, I already posted ad nauseum that I think the only dropped-header application with reason for being, is what Jim Roche wrote, who WAS a manufacturer's direct manager and wrote above. Dropped-headers are unrequired unless the 18/24" riser dimension cannot be met any other way!

I know you know more about steam than any other human being on the planet. I accept that as gospel - with this one exception. You have fostered a solution to a problem that does not exist.

I am tempted to suggest, a dropped header with the same size header as the twinned riser piping - will have WETTER steam than a properly sized non drop-header configuration!

If however the horizontal "header/manifold" is AT LEAST the same diameter (in square inches) as the two combined risers, we have effectively reduced steam velocity - and would allow water-carry to drop off the final riser(s) and be carried back to the boiler via the equalizer.

Since velocity is the means with which water-carry is encouraged, slowing it down will result in the reverse. If you have two 2" pipes going into a single 2" dropped header, you have made the velocity higher and the water-carry worse.

Do you agree?

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Steamhead

I think we have two different issues here

The velocity in the header itself, and how the steam gets into the header. Don't think for a moment that I don't respect your knowledge of steam, Ken- us two, Dan, Noel, Mad Dog and the rest form a truly knowledgeable steam heating fraternity.

First, the steam going into the header: Jim is right that you need at least 18-24 inches of riser to the header, depending on what is specified for the boiler model you are using. However, most piping diagrams I've seen state that this is a minimum height. Or, to put it another way, you'll have problems with less height, but more height is OK.

Those of us who have seen the Weil-McLain glass-piped boiler can attest to the need for a minimum riser height, since we can see the water trying to get up those 24-inch risers. What I remember most, however, is what happened when they dumped a bit of oil into the water. Suddenly it was able to overcome the height of the risers and get up into the header! We all know what happens in an actual steam system under these circumstances. So increased riser height, whether in a drop-header or not, will minimize carryover if the water gets less-than-squeaky-clean. But in a lot of cases, the drop-header is the best way to get the increased height.

I remember Dan wrote about his friend Ed Bratton, of Hudson, NY, who at that time was the only person he knew who still installed steam. How things have changed since then! One of the things Dan noted was that Ed took his risers to the header as high as he could- almost to the ceiling, leaving room for the header itself. This insured nice, dry steam.

Will continue shortly, The Lovely Naoko has dinner ready.....

Ken_8

Frank,

Your recollection of the pyrex piped W/M and mine are not the same.

I witnessed total chaos within all elements of the pipe. By total chaos, I refer to lots of water splashing up the riser, into the header and back to the equalizer - from the minute the boiler actually steamed - until we opened the ball valve and shot steam (laden with tons of water) 50' across the parking lot!

That was without the oil contamination. WITH the oil contamination, the foaming and suddent apparent false reading of the gage glass (read empty) - when in fact instead of the header having violenting swirling water screaming through to the qualizer - it became foam and virtually overwhelmed any steam that may have been able to develop.

Granted, for our "demonstration" we ran that thing at over 5 # to illustrate the cahos within; but at no time at ANY pressure did anything resembling "dry" steam ever occur!

Based on what I saw, it is my belief that the risers could only have true, "dry" steam, if there was some absurdly sized twin 4" risers, 36" tall, on a boiler (if one ever existed) that was rated at 200 S.F. of EDR!

Since that boiler has yet to be invented, we must deal with less than perfect equipment that does exist.

The water within the risers is NOT just the result of the "splashing" that occurs with in the steam chest. It is mostly the result of "water-carry" which primarily has to do with the speed of the steam entering the riser. Granted, a 36" riser will have less water carry at the top than a 24" But the riser diameter, has many more times the impact, than the vertical height!

Which would you rather have on a 300 SF EDR steamer; a single 4"x24" riser entering (after a swing arm) a 4" header, or: a 3"x24 riser, reversing into a 3" dropped-header? Yes. I know you probably wouldn't use a drop header on a single riser application, but humor me a second here.

My fear is, you will say the 3" with dropped-header.

Your suggestion that "block stress" is eliminated with a dropped-header suggests you are unfamiliar with proper piping with "standard" riser/header and proper union locations. We don't put them on the cross header, we put them in the risers - before the swing arms! There is no stress and line-up is easy.

In all honesty, since the vast majority of our steam boiler installs are oil to gas conversions, we use the W/M EG series. They have dual 3" riser tappings. That is the primary reason we use them. Wet steam with a single 3"x 24" riser nipp. on the typical 200-400 SF model is virtually non-existant. The extremely slow steam velocity and virtually non-attendant water carry is probably the best of any boiler made.

Nonetheless, I can see where lesser tappings and larger systems can be problematic. W/M's oil boilers are also decent size @ 2.5" riser dia. I suspect the former 2" holes were deemed insufficient - which is why they changed the entire casting layout to twinned 2.5"ers.

Thanks for putting me in the same class as Noel, Matt, Dan and yourself. It's nice to soar with eagles once in a blue moon (:-o)

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Steamhead

When I saw the glass-piped Weil

the water never reached the header when it was clean, but a little bit of oil caused the total chaos you describe. It was a real eye-opener for me!

Here are two of the photos I took the day I saw the Weil. The first shows it steaming with clean water- note the water getting up the risers about half-way. The second shows it steaming with dirty water- total chaos! Even a 3-foot rise to a drop header may not completely stop that kind of carryover, but it would minimize it, maybe to the point where it wouldn't drive the owners crazy with banging until we could get there to clean it.

In the example you give, if the boiler had a 4-inch tapping I would certainly use a 4-inch riser- as high a riser as I could make it. A 3-inch riser tapping might be OK. If it had a single 2-inch tapping I'd make the horizontal to the header the same size as the header itself, so when the steam hit the header it would already be moving more slowly. Then, any water that reached the header would just dribble into the header instead of being thrown therein.

I agree that the best place to put unions is in the risers as you state. This gives yet another place for the piping to "give" as the boiler expands. The extra swing joint in a drop header would only add to this, not detract from it. Dan would call it "wearing a belt and a pair of suspenders".

If I remember correctly, the W-M EG and EGH series have the top sight-glass tapping about 6-inches down from the steam outlet(s). So, if I'm right, a 24" riser nipple would actually give you about 30-inches of height between the maximum waterline and the header. If W-M specifies that 24" nipple, that was a real good move and is one reason you get such dry steam from these boilers.

Looking through this thread, I didn't see anyone saying that the riser pipe size didn't matter. Of course it does. But we can dry out the steam even more by using taller risers and bigger headers too. And I love the lesser amount of time it takes to put together a drop-header on a boiler with two or more risers- customers appreciate this on a 10-degree day when they are shivering, and as Ron says it can result in fewer callbacks.

And we've never had problems with an inspector on a drop-header job.

Unknown

Few more questions

Had to quote a little of your post .

" I am tempted to suggest, a dropped header with the same size header as the twinned riser piping - will have WETTER steam than a properly sized non drop-header configuration! " What if the same size piping for both boiler supplies is used on the boiler main , but it is not dropped ? Your statement would not be exclusive for just a drop header .

" If however the horizontal "header/manifold" is AT LEAST the same diameter (in square inches) as the two combined risers, we have effectively reduced steam velocity - and would allow water-carry to drop off the final riser(s) and be carried back to the boiler via the equalizer. " Very true , but how would dropping into an oversized boiler main adversly affect performance ? Or do you think it doesn't affect it at all ?

Unknown

I saw it late in the day

after maybe 10 or so showings . The 2 risers and main were full of water right when it started steaming . I'm not sure if it always steams that way or it was leftover oil from the past showings . Definitely an eye opener .

tommyoil

I use

90% W/M. Some Peerless,some Burnham upon request or demand.

Steamhead

That explains it, Ron

I believe the pics I took were of its first demonstration that day, and the water was clean.

Boilerpro_3

One thing not being looked at

is the size of the steam chest in the boiler. If I remember right, the water is really close to the exit tappings on the EGH, so in order to control carry over. large tappings are necessary. On the Dunkirk Plymouths, there is more space, but the connections between the sections are small and the boiler is sidetapped, so 2 1/2 inch risers will do. In the Burnham Indenpendence, the steam chest is quite large (at least by modern standards. I believe there is about 8 inches from the water line to the exit tappings, so the water has already had a chance to settle down before it even reaches the little 2 inch risers.

IMHO, which I would love to see tested, boilers with larger steam chests can deal with smaller tappings. What I would love to see is the Burnham Independance equipped with 2 1/2 or 3 inch tappings. However, I believe Glenn said that with the recommended piping, the boilers produced steam with only 1 percent water, which is pretty dry.

I wonder how much performance difference there is under poor conditions(dirty water, Ph basic water,etc) on a large steam chest with small risers versus a small steam chest with large tappings?

Boilerpro

Mark Hunt

Droppers


IMHO, if you all believe I have one, is that a drop header is really meant to solve a water line to steam main problem.

Almost every new steamer requires 24" from the top of the "normal water line" to the bottom or center of the new header. I can't do that sometimes and the dropper is the only answer.

Why the 24"? Because steam chests are smaller today than they were 75 years ago.

I have an install this week where the HO wants the new boiler raised as high as I can get it. Last one was flooded.

I'll raise the boiler, but I will HAVE to use a drop header.

But when I don't have to use a dropper, I don't.

No difference in performance, just using the right option at the right time.


Mark H

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Unknown

I would guess that

the oil boilers built for steam or hot water , with coil ports for both , would work great for steam . The opening through the boiler for the water coil makes a great steaming chest . I would think for gas steamers , it all depends on how big the upper push nipples , and surrounding steaming area is ? Do any gas steam boilers incorporate a big steam chest ?

Unknown

We built a steam boiler for a college HVAC

class this past winter . I suggested we pipe part of the header in glass , but we simply had no time to do it - the class started the next week . I bet the head of the course , Eugene , would be willing to repipe the boiler partly in glass - actually seeing the steam go through the system is greater than trying to describe it . Does anyone know of a specialty glass company that makes this kind of equipment ?

The Wire Nut

Did anyone

ever answer Jon S.' original question that started this thread????

Mad Dog

C'mon guys

You are all stating obvious and well-known reasons for using them. Ken's heard it all before and probably agrees. Me thinks Ken is just just trying to get a rise out of an otherwise innocuous subject. Mad Dog

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Jon S.

Never mind.....

Steamhead

I think

W-M used Pyrex piping. Maybe Corning makes it?

The Wire Nut

Mad Dog,

Thank you for the dose of sanity!