Forum / Strictly Steam / under size steam header

## under size steam header (15 Posts)

• ### under size steam header

what will happen when you under size your boiler header have a boiler with 2 5inch risers off of boiler they go into a 6inch header boiler manufacure wants a 8inch header
• ### You'll have a LOT of problems

wet steam, high fuel consumption, uneven heat, banging, water-level problems in the boiler........

Do it right. Change the header.
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• ### yea

u got to do what the manuf. want if u ever have problems down the road, but 8" does seem excessive. 2- 2.5" pipes don't even come close to 1- 6" flow rate, so what is it based on?
• ### That's 2) 5" risers,

which makes sense for an 8" header. Must be a pretty large building...
• ### wet steam poor heat

2.5 x2.5x 3.1416x2 = 39.27
3x3x3.1416= 28.27
4x4x3.14=50.26
Cost is what you spend , value is what you get.

cell # 413-841-6726
• ### I agree with your conclusion Charlie,

but not sure I understand what you mean by your math. Can you explain further please?
• ### yes charlie please explain...

this is my math, if i'm wrong i need to know where
the radius of a 2.5" pipe is 1.25"          and the radius of a 6"pipe is 3"
1.25x1.25x3.14=4.90sqin +                        3x3x3.14=28.26sqin
1.25x1.25x3.14=4.90sqin
= 9.8sqin
i can't get it to stop underlining!!!   but i'm pretty sure that u add the area off the two 2.5" risers to get the tottal area of the two, but if i'm wrong and you multiply them together it's still only 24.01sqin.
• ### it is two 5" risers pipeking not

two 2 1/2" risers. we are in the big leagues now boys.
Cost is what you spend , value is what you get.

cell # 413-841-6726
• ### Oh, I think I get what you're saying Charlie...

The area of (2) 5" risers is Pi*Rsquared = 3.14*2.5squared, times 2 risers = 39.27

The area of the current 6" header is PiRsquared = 3.14*3squared = 28.27, which is too small

The area of the spec'd 8" header is PiRsquared = 3.14*4squared = 50.26, which is larger than the total area of the 2 5" risers.

The minimum header size would be slightly larger than 7", which means you need an 8" header.
• ### and you can drop the π

anytime you are comparing round pipes.  Squaring either D or R will give you the answer.
• ### I kept in Pi to show

the actual area diffrence not ust the proportional  difference. If the numbers differ by larger amounts it seems to make the problem more visible. When comparing in my head I leave out the Pi. Unless it is right after supper then I have the pie if it is there to be had.
Cost is what you spend , value is what you get.

cell # 413-841-6726
• ### Good point...

multiplying all variables by the same constant does just give you more messy math. I hadn't really ever thought about it.

I'm kind of anal though, and I think seeing the real numbers, not just proportional numbers, somehow makes me happier, whatever that means.