How much head?

Boston

Makes perfect sense.

Sorry for pushing some of your thoughts into the gutter.

I think I knew 90% of that, but you all connected the dots.

BC

Boston

Heas calcs / pump sizing

It just occured to me reading another thread that I don't understand how to calculate head and I generally use a 007 and see if it works.

I have a job that has a small airhandler in the attic, so figure 27 feet above the pump, 1 1/4 inch w-m pex, figure 35-40 feet of piping. The 007 pumps but now that I think about it it wtook a good while to reach temp and click the aquastat on. Is this an example where a 007 does not have enough head?

I sense head is resistance to flow, as compared to volume of flow. And the 007 can onl lift so much water so high, thinnner pipes means less height. Is there a better way to look at it?

Reading this I feel dumb, but never learned about how to calculate. Most jobs an 007 seems to work fine.

Empire_2

Brian

Great question and many in here will jump to set your mind at ease. Head has to do with resistance to flow which is created by the pipping itself, valves, fittings, etc. In a closed system head has nothing to do with height, but rather the length of the actual circuit. Open systems, like sump pump, condensate pump,..now that is where height comes into place. Quick reference to figure required head, (Total length of run, in feet, add 50% to that, Multiply by .04 and the result is pump head required. B&G has a great book called "It ain't the same". Pump head, water and psi relationship, expansion tank information that I think is a must for everyone.

Mike T.

Brad White_158

Forget height

in a closed system. Open systems have to "lift" against heights open to atmosphere. In closed systems think of a Ferris wheel. What goes down draws what comes up. A continuous siphon which just needs a little nudge.

What creates resistance in a pipe system is basically friction losses, that film of liquid in contact with the side of the pipe, plus dynamic losses, the force of flow changing direction. (Try taking a sharp turn of the Sawmill River Parkway at 45 MPH versus the recommended 10....those are dynamic losses and a call to AAA).

Essentially you need to know the longest (most resistive) run of piping from circulator to emitter and back again. Every fitting and foot of piping at a known flow rate along that path creates resistance based on that flow rate plus the emitter, the coil in your case.

Forget the branches and such; if you can hose water to the vegetables on the far side of your garden, (the longest run) you can water petunias at your feet.

If I guess at the flow rate you intend in the example you gave as being say, 10 GPM, the piping you cite would have a pressure drop (at 150% of length to include fittings, call it 60 feet equivalent), of 1.5 feet. If the coil is 2.0 feet just a guess, plus a valve or two gets you to 4.0 feet of head, you will balance out at about 9.0 GPM flow rate.

All of this is a guess not knowing your flow requirements but is in the middle of what would be reasonable, in my opinion. The 007 should be plenty (you lucky dog you).

Brad

Brad White_158

What Mike T. said....

Fast Fingers Mike they call him

SynrG

How much head?

Are you asking men or women? (Sorry, couldn't resist!)

SynrG

Brad White_9

I don't get it.

Really.

SynrG

Apparently not...

...and you have my sympathy.

SynrG

ScottMP

Thats Hunt getting me back...

My opinion is that you can never have enough head.

Scott

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SynrG

Spoken

like a true man! LOL

*ponders making a pun on building up a head of steam but decides to leave it alone for now*

SynrG

jackchips_2

And plumber

Scott said "hey babe, take a walk on the wild side".

SynrG

Been there...

...done that. (And have the pics to prove it. ROFL)

SynrG

Mark Hunt

NOPE!


Not me.

Apparently there are others that know about you and your "little" problem Scott!!

Now THAT is Hunt getting back at ya'!!

Mark H

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