15 inches to drier steam..... Boilerpro

Boilerpro_3

Was looking at some steam boiler (you mean you're supposed to read those?)installation instructions and it recommends a minimum of 15 inches of horizontal header between the last boiler takeoff and the first system supply. This is so the water has a chance to settle out of the steam. Was wondering some of your opinions on this. It seems to make alot of sense, but I don't see many installs posted here (along with mine) that are piped with this extra piping. Maybe we are missing something here.

Boilerpro

J.C.A._3

Do we count....

from the first elbow of a drop header, or from where the (hopefully) 2 , risers come out of the boiler?
I've done quite a few steam jobs, and always have questions , as to where the measurements for minimums are taken from.
Just finished drop header job, and followed the instructions to the book(except for a shut-off between the return on the hartford loop and the riser to the boiler return, Personal choice...)
Can the manufacturers shed some light on this?
If I had piped in the fashion you explain. the header would have been about 2 feet past where the boiler had to meet with the 2 risers, and at least a foot behind where the return header met the lower side of the Hartford loop . Why mess with success? The new job was quiet, and the only problem I had was with a slow main vent. Chris

Mad Dog

With a nice blown up header and in many cases a drop header

figures like that are moot....If the steam ain't dry by then...it ain't never gonna be dry. Mad Dog

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Steamhead

Which boiler

were you reading the instructions for?

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J.C.A._3

Steamhead,

It is a Burnham IN8, and I wanted to keep it on the exsisting pad. Chris

Steamhead

The IN7-12 piping diagram

shows a close nipple between the second riser and the steam main takeoff. So no problem there.

How about it, BP? Which boiler were you working with?

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Boilerpro_3

Dunkirk Plymouth Steam (residential)

Steamhead

They sure do

First time I've ever seen that. I looked at the Columbia diagram, which also uses side tappings, and they don't specify a length there.

You could always elbow over from your risers before piping the horizontals to your header. If you wanted to get really fancy, you could put drops there too. How about it- a "double-drop header"?

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ed wallace

spacing

so you are saying with a dropped header you dont need the 15 in called for by dunkirk ?

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Boilerpro_3

Do you care to give us

a sketch of that, Steamhead? I also think that 15 inches should be a straight pipe leading directly to the supplies...no 90's to stir up the water back into the steam. Something like this was mentioned on a recent thread. Use 45's instead of 90's to help the steam dry out. I think the only advantage to a drop header when looking at steam quality is being able to get taller risers. If you think about it, when that steam and water come crashing down into that drop header, it probably mixes them up quite well. I'd like to see some of these piping configurations in glass sometime just to see how all the elbows and how the lengths of the straight pipes effect the steam quality. So Steamhead, when are you going to build a steam lab, like those we've seen here for hot water boilers? I bet you could get many contributors for it here at the wall... including some companies to contribute boilers to put thier products head to head with competitors. Wouldn't it be nice!

Boilerpro

Mad Dog

I'd like to see the sketch to be 100% clear, but

from what I understand of what you are telling me, no, I would not worry about it, if your header is upsized or dropped. However, if that would void the warranty with Dunkirk, you'd better do it. Most times they are just guidelines. Sometimes my headers aren't purdy, which crazy angles and extra fittings, but dry steam is the goal - not beauty. Mad Dog

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peter desens

warranty

Warranty not an issue.

The fifteen-inch is a recommendation for optimum system performance, and in no way will effect the operation of the boiler.

If everything else is done according to the diagram, decreasing the fifteen inches to twelve or even less will most likely not have any effect.

Peter Desens
Technical Service Manager
ECR International - Dunkirk Boilers

Steamhead

Thanks, Peter

for clearing that up.

BP, I have a particular system in mind for a double-drop offset header, but it's a Weil-McLain EGH rather than a Dunkirk. It's currently piped with the steam takeoff between the boiler riser connections, and this method would let me move the header over without moving the boiler. I'm not good at sketches but I'll see what I can do. I'll certainly take pictures if/when we repipe this one!

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Unknown

I think I'm with Peter on this one

It would benefit the steam and fuel consumption if the header were dropped(with 45s, optimumly), if the header were oversized, and the 15" before and the 12" after were all maintained. I also think a good distance should be left between the system takeoffs, because they lift the water as it passes, right into the next tee, if it is close. 12" between tees would eliminate this.

It isn't a perfect world, but it gets better every time we bring this up. As many of these things as you can give your customer will save fuel. They aren't all required to keep the boiler in good condition. Ignore all of them, and the boiler will dry fire, and that IS a problem. A dry fired boiler is NOT covered by warranty, and there will be signs if that happens.

Sometimes a few inches are compromised to meet the needs of the space. It costs in fuel, but there won't be anything to compare it to. What do you do?

You do your best for your customer. I already knew that.

Noel

Boilerpro_3

Is that 12 inches after the takeoff from the header ...

to the next takeoff or the equalizer?

Boilerpro

Unknown

both

only the 12" beyond the last is asked for in our steam boilers. No mention of two takeoffs.

I'm only talking ideal, though. Sometimes I think too much. Showing a one take off system in diagrams, the steam always gently lifts the water "pile" right under the tee. That can't be good for the next tee, if it is really close.

Noel

clammy

pipe equivelents

sorry bout the spelling i know you guys know what i mean but if fitting have a direct straight pipe equal i believe a 90 is equal to about 3 ft of straight pipe so a drop head really gives you dryer steam by increasing your heigt from the water line by adding extra fittings as for the distance from the last rise connections i try to always make the distance as far as i can and i've always tryed to use 45 instead of 90 i believe it gives any moisture a chance to roll back down the header and into the equalizer also if you increase your header size to 2 sizes above the existing system lines 3 " for a 2" systems connection really slow down your steam velocity to the point that you really aren't carring water into the header and end up with some really dehydrated steam i've done a number of times on job with excellent success it's produced steam so hot it's peeled 20 years worth of paint right off quite cool and on low pressure 1 1/2 psi steam is king long live the ones out there

Boilerpro_3

Picture in your minds eye..

What happens when steam (with some water)is rushing across the header. In the longer straight pipe the turbulence is minimal and the water settles to the bottom. However the water and steam are still moving at a good clip. Then all of a sudden the water and steam hits a 90 in the road. Once the water is moving straight in wants to continue to go straight so its rides up the outside of the 90 and begins mixing again with the steam. Its sort of like driving down a road you don't know well at the speed limit with a big gulp of hot coffee sitting in the cup holder. Suddenly you hit a 90 in the road that you didn't know about. Remember what happens to that hot coffee that was just quietly going along for the ride... Its now all over the dashboard and the carpet. I suspect water riding along quietly with steam is going to do the same thing when it hits a 90.

Boilerpro

greg_7

Drop heads

I'm not so sure about the coffee cup analogy.

In a system I've been working on, there was two 2" copper risers off of the side tappings on a Dunkirk that each separately connected to one of the two mains on a one pipe, dry return system. Only one of the risers was equalized and it was also hooked in to the hartford loop. The steam was slow and the gas bill high.

We repiped the risers with black pipe drop headers 24" above the water line and had to take the first main off the header about 5" from the boiler riser.

The new set up steams fantastically. Radiators are sizzling and the equalizer is hot, so it seems that the water is being forced out by thge dropped header. I thought the turbulence would help shed water from the steam.

Boilerpro_3

Actually, I was talking about steam and water in the header

when it is moving horizontally towards the drain and then hits a turn on the way to a takeoff. I imagine you bumped the risers to 2 1/2 inch. This in itself would cut the velocity in half.

Boilerpro