Pipe Sizing

todd s

I was wondering how crucial mantaining full size pipe was for a given btu load?

The reason I'm asking is, we recently replaced a boiler for a customer. This unit serves 3-45,000 btu Modine heaters and an old B&G pool heater. The old boiler had 1"pipe run to the pool heater and 1.25" to the three modines. When we installed the new boiler, we changed the piping to the pool heater to 2" and the customer can't believe the differance. The pool never heated so fast.
The pool room was heated by the modines and a 225,000 warm air furnasty. This unit now needs to be replaced and we are discussing his options. He would like to add another Modine 45,000 to the three existing (and possibly another zone to supplement it). If 1.25" can carry 140,000 we would need to go up to at least 1.5" to handle the 180,000. The piping comes off the boiler from a 2" x 1.25" tee. I would rather not have to repipe the boiler, if we change all the piping to the units to 1.5" would the 2 x 1.25" tee have to be changed also? Is that one spot going to restrict flow so that we can't get the full btu's out of it?
I always see 3/4 tappings on indirects and air handlers, however usually they need to be fed with 1" or larger pipe. I know we need to bring so many btu's to the unit but it seems that it would just be a bottleneck at the smaller fitting. Of course this is not the case but it is something I never fully understood.

todd s

Sizing pipes

I was wondering how crucial mantaining full size pipe was for a given btu load?

The reason I'm asking is, we recently replaced a boiler for a customer. This unit serves 3-45,000 btu Modine heaters and an old B&G pool heater. The old boiler had 1"pipe run to the pool heater and 1.25" to the three modines. When we installed the new boiler, we changed the piping to the pool heater to 2" and the customer can't believe the differance. The pool never heated so fast.
The pool room was heated by the modines and a 225,000 warm air furnasty. This unit now needs to be replaced and we are discussing his options. He would like to add another Modine 45,000 to the three existing (and possibly another zone to supplement it). If 1.25" can carry 140,000 we would need to go up to at least 1.5" to handle the 180,000. The piping comes off the boiler from a 2" x 1.25" tee. I would rather not have to repipe the boiler, if we change all the piping to the units to 1.5" would the 2 x 1.25" tee have to be changed also? Is that one spot going to restrict flow so that we can't get the full btu's out of it?
I always see 3/4 tappings on indirects and air handlers, however usually they need to be fed with 1" or larger pipe. I know we need to bring so many btu's to the unit but it seems that it would just be a bottleneck at the smaller fitting. Of course this is not the case but it is something I never fully understood.

hr

You could

use a increaser right at the tee to step up to 1-1/2". That short section would not be a big deal.

Actually I might just stay with the 1-1/4. You can move 180,000 through a 1-1/4 with a 4.5 FPS velocity. A tad over the common 4 FPS max.

I feel 4 FPS is a bit "engineer" conservative I think CDA allows 6 for DHW?

Spread the delta T to 25 and you are well within the 1-1/4" pipe size. Assuming you are moving water through copper tube?

hot rod

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todd s

Thanks hot rod

What is that attachment?

hr

Treat yourself to

Siggys HDS, on sale at www.hydronicpros.com
It will do heat loss calcs, pipe sizing, expansion tank sizing, buffer tank, injection mixing, etc, etc. It's a great way to size "on paper" before you build the system. Allows you to play "what ifs"

A very hand, inexpensive software to own. Load it on a lap top for an excellent troubleshooting tool bto carry into the basement

Try the demo at his site.

170° water at a 25° delta t, flow rate of 14.7 gpm, will move 180,000 btu in 1-1/4" copper with 3.6 foot of head per 100 feet of pipe at a 3.6 fps velocity.

hot rod

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Mark Eatherton1

HR....

Happy New Year my wet head friend. You are one of THE most helpful people I know, and here's a tip to save you time, trees and gallons of ink.

To the upper right side of your keyboard is a Print Screen button. Whenever you push that, it takes a snap shot of the screen and pastes it to your clip board. If you open MS Paint, and click on Edit, Paste, the screen shot you saved with Print Screen will magically appear.

Save this as whatever name under whatever file you want, as a JPEG, and you will save having to print the picture, take a picture of the picture, and up load that to your PC.

"I always wondered what that button was for..."

Happy New Year my friend!

ME

Weezbo

i think the computery thing is something i need to Save.

Iam not good at some computer stuff so i am here to save the thread in case it doesnt work out saving a picture to something or other and reprinting it to a file some where...While Frank Loyyd Wright may have had a brief soirre to alaska, i have never worked on one of his homes,however, insulation seemed to be in shorter supply in the more vintage homes of that comprable era ....let me echo the advantage in using Insulation as an economical "Tactic:)" Thanks ME. Sweet dreams mr and mrs Hot Rod *~/:)