Drop Header Question

xcinek

Hi,



 I'm doing a drop header as you can see in the photo.  I have two questions as to which is better.



Question 1: When I make the drop header and I turn the raisers so that my drop header start all the way to the right. Is this OK?



Question two 2: I want change so that the 2 mains leaves from 3 inch header as in photo.



Or should I do as photo number 2 where 3 inch main goes into 2 mains.



Independence IN8 Gas Fired Steam Boiler, NG, Electronic Ignition,- 245,000 BTU



4th photo is my original set up which I'm changing. header is 2"

Just looking for some imput.

pecmsg

Drop Header Question

I'm guessing you want it above where the rag is?

Steamhead

What size is the existing header?

and what model is that boiler? You might be able to connect both those risers to the existing header if the size is right..............

xcinek

Existing header

Existing header is 2 inch



manual says do 3 inch thats is why i want to change everything.

Hap_Hazzard

3" pipe

has twice the cross-sectional area as 2" pipe, so when you bring two 2" risers into a 3" header, the velocity will be the same.



Regarding your design, there's no reason to swing the swing-arm on the right so far to the right. The swing-arms do not need to be parallel. As long as they meet the riser a couple of diameters apart you've got enough separation. You can use that length of pipe to give you more vertical rise instead.



If you keep the header roughly in the same place, but replace it with 3" pipe, you'll be able to bring the boiler risers straight up before dropping to the height of the header. This has the advantage of allowing water droplets to fall back before they even reach the header.



You should leave those two system risers right where they are and connect them to the new header. Your system risers should always be connected independently to the header.

xcinek

Thanks for the info

Thanks for the input. I either put one all the way to the right. or bend the the header to the right because I dont have to much space or I have to move the water feeder line and the return lines.

xcinek

.

Are you saying its better to put in a 4 inch header. I want to slow the steam down.



Manual says 3 inch.

Hap_Hazzard

4" vs. 3"

Sure, 4" would be better--bigger is always better, within reason, but there's something called diminishing returns. If the manual says 3" is adequate, it is, and the small improvement you'd realize from using 4" pipe would not justify the added cost.



The purpose of the header is to reduce the velocity enough to allow entrained water droplets to precipitate. If the manual recommends a 3" header, that will give you the right velocity. Since the cross-sectional area of each riser is half that of the header, that means the steam will be moving at the same velocity through the risers. That's a good thing. It doesn't mean the header is too small; it means the risers are plenty big. If you run these risers straight up for 3 feet or more, most of the water will fall right back into the boiler.



Of course there's more to good header design than the diameter of the pipe used. The 90° exits of the system risers allow the steam to exit while water droplets continue moving in a straight line due to their greater inertial mass, and the proper orientation of the equalizer to the end of the header provides an easy path for that water to return to the boiler along with any condensate that forms inside the header.

JStar

Header

The magic number is based on exit velocity.



To stay at 15 feet per second, a 3" header will handle 106,416 BTUH.

At 20 feet per second, 141,888 BTUH.



A 4" header @ 15 ft/sec = 183,312 BTUH

A 4" header @ 20 ft/sec = 244,416 BTUH



Staying with a 3" header will make your velocity 34.53 feet per second. Low, but not low enough for me.



I would personally go for a 4" header. I tend to think that you can never oversize a header.

xcinek

.

Great info. I'll look into putting 4 inch header



As to height of raisers right now I have 29" high no problem raising it to 36"



As previously posted I changed the setup to this.

xcinek

in Process

I m currently working to have this done.



I decided to go with 4 inch pipe.



See photos.



The guys at the plumbing store looked at me like I was weird put in a pipe like this.

xcinek

After Photos

Finished Product



4 Inch Drop Header

2 King Valves

Mud Leg

STEAM DOCTOR

Equalizer

Is the horizontal leg on the equalizer backpitched?

xcinek

Back Leg

xcinek

.

It is slightly but you have a 2 inch return where it will push all the water down. I dont think it should create water hammer.







What do you think ?







I will replace with 45 degree elbow if it creates a problem.