Author Topic: pump specs  (Read 3937 times)

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artv

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pump specs
« on: June 22, 2011, 03:09:17 PM »
Hi all ,..The info on the  pump I'm using says that, at ten feet of head ,on low speed, it will pump 2 gallons/min.* grundfos_flowUPS15-58.pdf (78.66 kB - downloaded 521 times.)
My ?....does this still hold true , because I'm pumping into a 12 gal tank, which then goes into a 32 gal tank ( I thought it was 40 gal) ,then up to the roof.
Will the 44gal of tank water reduce the gpm??............thanks for any help.....artv

Simen

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Re: pump specs
« Reply #1 on: June 22, 2011, 03:47:14 PM »
If you pump the water in at the bottom of the tank; yes. You have to consider the whole continous height of the water.

If, for example, you have a 4 feet tall tank standing on a platform 10 feet up, and pump in water at the bottom, the lifting height for the pump will be 10 feet when the tank are empty, and 14 feet when the tank are full. If you have the hose from the pump at the top of the tank, the height will ofcourse be 14 feet.
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artv

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Re: pump specs
« Reply #2 on: June 22, 2011, 07:18:15 PM »
Hi Simen,....So does that mean, regardless of the volume of water,..the height is the only concern??
I thought maybe ,the the extra amount of water in the tanks ,would reduce the gpm flow of the pump??
Thanks for the reply................artv

wpowokal

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Re: pump specs
« Reply #3 on: June 22, 2011, 08:19:28 PM »
you understand correctly.

Allan
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Simen

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Re: pump specs
« Reply #4 on: June 23, 2011, 01:46:56 AM »
Yes, height are the only concern. :)
One have to consider the height from the top of the waterlevel from where you're pumping, to the top of the waterlevel to where you're pumping the water. The pump would do the same amount of work no matter where inbetween the two levels it sits.
(Though, those Grundfos pumps needs to be primed, so the best place for them are close to the source. ;) )
I will accept the rules that you feel necessary to your freedom. I am free, no matter what rules surround me. If I find them tolerable, I tolerate them; if I find them too obnoxious, I break them. I am free because I know that I alone am morally responsible for everything I do. - (R. A. Heinlein)

Photon

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Re: pump specs
« Reply #5 on: June 23, 2011, 08:40:55 AM »
Pumping head = Height of tank + Loss in fittings/pipe


don1

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Re: pump specs
« Reply #6 on: June 24, 2011, 01:32:35 AM »
artv,
 May I put my two cents worth in hear?  First  I believe if the tanks are in the basement or at the bottom of the loop they would have no bearing on the GPM.  Something no one else has hit on hear yet is, if you have a closed loop system the head the pump delivers does not come into play so much here.
If you have a pipe that goes from the tank at the bottom of the system up to the panel on the roof and a return pipe back to the storage tank and the pump anywhere in the loop the roof could be 80 feet in the air and the pump will still circulate the water.   Why? because both the out pipe and the return pipe are full of water and have the same gravitational weight as each other irregardless of length. So all the pump has to do is create a suction on the return pipe and a little pressure on the out pipe and the water will circulate. That is why the grunfus pump was designed as a circulater not a pressure pump and also why you are not seeing much for head pressure.  The head pressure and pipe length now become componets in calculating the water flow rate.
.  I hope I was able to convey my thoughts in a way that it could be understood as I am not the best at writing down my thoughts. Hope this helps,  don

artv

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Re: pump specs
« Reply #7 on: June 24, 2011, 06:51:32 AM »
Thanks for the replies ,..So Don1,.. it is safe to say that I'm circulating 2 gpm (because it's closed loop), the volume of water balances out on both sides of the pump.(right?)
The reason for wanting to know is, I know my collector on the roof holds ~4gal of water. It takes 1min of circulation before the hot coming in starts to cool , so ~2 gallons.This info will help when since I going to try using a programable timer to control circulation.
Thanks for all the help.....much appreciated......artv

don1

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Re: pump specs
« Reply #8 on: June 25, 2011, 02:42:15 PM »
artv,

  Because of all the possible variables I would only be guessing here as to the gpm in your loop. Assuming that the out and return pipes are well insulated, something to consider might be what happens if the gpm is less    If the gpm is less the water going to the storage tank through the pipes will just be hotter.  If the gpm is more the water will be cooler in the pipes.  I believe that the total btu's transferred to the storage tank will be close to the same in ether case.
Hope this helps and best of luck don.