Flow and head-feet

Mike T., Swampeast MO

What type of pipe/tube?

As Brad mentioned the "equivalent length" method is MUCH easier to use and very reasonably accurate at the general velocities in hydronic systems.

You can find them on the web. Try Google. Include "equivalent length" QUOTED in your search string along with the type of pipe/tube.

www.copper.org has tables for copper tube & fittings but there's so much there that things can be a bit difficult to find.

Mark_46

Taco 008

I'm curious to know what the flow rate of the 008 is. But I dont understand the total head-feet rating?

When I look at the GPM flow curves provided by Taco, flow increases as the 'head' decreases. I presume 'head' is pressure drop in the pipe circuit, correct? (pipe size, length and number of elbows)

Alan(CaliforniaRadiant)Forbes

That's right

The longer the straw, the harder it is to blow through it.

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Mark_46

Standards

Alan,

Thanks.

Are there standard pressure drop ratings available for pipe diameter, length and 90 and 45 elbows? If I had that, i could then add up everyhting in the circuit.

Brad White_9

Fitting Losses Depend

on pipe size and velocity. A simple way is to assign each fitting a value equal to it's "equivalent feet of pipe" to which is added the actual straight pipe itself. The total equivalent feet or TEL is then multiplied by the pressure drop factor ("feet of head loss per 100 feet of pipe") for the given flow rate.


If you want, e-mail me off line and I will give you a copy of a spreadsheet I developed that does just that.

Brad

Joe Mattiello_2

The Taco 008 has a relatively steep curve, and is a good candidate for systems requiring flow through long lengths of piping. Hope I didn't over simplify this, if you have specific questions I will be happy to answer them for you.
Joe Mattiello
Technical Support Technician
Tel. 401-942-8000 X 484
Fax. 401-942-2360
1160 Cranston St
Cranston, RI 02920
joemat@taco-hvac.com

Mark_46

Great

Brad,

The spreadsheet would very much appreciated! I'm sorry though, I misplaced your email and I know you scramble it to avoid spamers. If you can, send me the file to my address. I believe mine displays in the forum? I have it checked in my options page. On second thought, here it is -lol.

rubberneck_72@hotmail.com

Mark_46

Actual circuit measurement

Joe,

Thanks. I dont think I have specific questions on the pump itself right now. What Im looking to do for now is measure the circuits this pump is feeding so I know what the flow is to the DHW tank and the two water coils. If I know that, plus water temps in and out and CFM flow over the coils I'll be certain the system components are sized correctly. Or completely frustrated if they are not ).

CC.Rob

As a HO, I've found the following Taco resources very useful for TEL calculations, pump selection (particularly in zone valve systems), etc.

http://www.taco-hvac.com/uploads/FileLibrary/TD01.pdf

http://www.taco-hvac.com/uploads/FileLibrary/PumpCurves.pdf

http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf

And Brad, would you please email me your spreadsheet? Would like to compare it to mine. Address in reply. Thanks!

Mark_46

Duh. I just realized email shows in the reply page

OK, I do in fact have your email ).

Mark_46

Hey Mike

Well the circuit to the DHW is 1" copper and the lines to the water coils are 3/4" PEX.

Mark_46

Hey Mike

The primary loop is 1 1/4" black pipe, the circuit to the indirect is 1" copper and the lines to the water coils are 3/4" PEX.

Thanks for those other info sources. Ill check them out.